<figure><img src="image_162.png" /><figcaption>**Fig. 3.29** Common toad (*Bufo bufo*) observed during field investigations, providing valuable data on local wildlife presence and ecosystem dynamics</figcaption></figure>

Applying the municipal catalogue of remarkable species for site PD in Nanry, France does not lead to any significant sensitivity of the site. During the field inventory, no noteworthy species were found. However, several invasive species were observed that may negatively affect agricultural cultivation. Therefore, it remains to be studied if the soil can be transported for compensation purposes as is or if particular measures to eliminate those species will be required.

No remarkable species were recorded during the field inventory of the site PF in Éteaux in France. Three noteworthy species listed in the bibliography may, in principle, occur in the enlarged study area including wet meadows and wooded areas, outside of the surface site perimeter.

The municipal species catalogue of Groisy and Charvonnex applicable to site PG in France mentions three remarkable species that could be present in the study area. None of them were identified during the field inventory and no other remarkable species from the bibliography were observed either. A few invasive species have been recorded in the study area and topsoil that is removed should be cleared of those species.

The list of flora species of the communes of Cercier and Marlioz applicable to site PH in France includes a considerable number of remarkable species, but none of them is present in the study area, and no remarkable species were observed during the field visit.

None of the remarkable species listed in the bibliography for Dingy-en-Vuache and Vulbens for site PJ in France occur in the study area and no remarkable species were observed during the field visits. Some remarkable species listed in the communal lists could, however, be potentially present in the area that exhibit sufficient characteristics to support those species. They concern mainly humid zones at the edges of the surface site candidate perimeter.

For site PL in Challex, France, four species are highlighted as noteworthy in the bibliography. Tow out of them may potentially occur in the area of the PL site. However, none of them were observed during the field visits. On the contrary, two invasive species were inventoried in the study area, which should be taken into account in the case of reuse of agricultural topsoil.

Summing up, no particular sensitivity of any surface site candidate could be established with respect to remarkable flora. However, some sites will require attention with respect to the treatment of invasive species before the topsoil can be re-used for compensation measures. The PB surface site design requires attention due to two remarkable species observed during the field visit and the large number of potentially present species listed in the bibliography in the larger area. This site is, therefore, still considered to have a strong sensitivity at its edges. No outstanding flora species were inventoried at the PA, PG, PH, PJ, PL and PF sites, but these areas require complementary studies during a preparatory project phase to confirm the state and to plan for the construction site activities. So in general, additional field visits are required to reliably assess the environmental impacts. The sensitivity of site PF is also considered strong due to potential remarkable flora at the very edges of the site. Attention will need to be paid to invasive species present in several locations, and this will need to be taken into account when considering the reuse of agricultural soil in other locations.

## Fauna

**Amphibians** For some groups of amphibians, identification down to the species level cannot be carried out without genetic analysis due to the strong hybridisation within these groups. However, an inventory based on bibliographical data and field investigations was established not only on the sites, but also for the perimeters in the vicinity of the site. Investigations were done during the day and the night for several months. Amphibians are frequently found in the vicinity of water spaces, creeks, rivers, and wetland zones.

Amphibians were observed in the vicinity of site PA in Ferney-Voltaire across the French and Swiss territories. Some of them are considered endangered in Switzerland. No amphibians are present on the surface site location. In
<figure><img src="image_163.png" /><figcaption>**Fig. 3.30** Reed warbler (*Acrocephalus scirpaceus*) observed during field investigations, providing valuable data on local wildlife presence and ecosystem dynamics</figcaption></figure>

the immediate vicinity of site PB in Presinge the bibliographic inventory was confirmed by the field investigations and the issue<fnref n="9" /> is big, and therefore the river zone will be entirely avoided by the project. The integration of a rewilding project in the site will help to raise the protection level of that zone further. The area is currently partially used as agricultural space. Site PD in Nangy and its vicinity have a low stake concerning amphibians. Although the site PF in Éteaux is not directly concerned, the immediate vicinity revealed species with a high stake. At site PG in Charvonnex and Groisy several amphibians are confirmed in the vicinity and few on the site. The stake concerning amphibians is also high in the vicinity of site PF. On the site, no issues could be identified. Some amphibians were observed in the vicinity of site PJ, but the site did not reveal particular issues. Some amphibians were observed in the larger area around site PL in Challex, including Switzerland. Some of them are listed as endangered and protected. The site does not host amphibians.

Summing up, the zones in the vicinity of sites PA and PD feature a few habitats that would give them a high value. For sites PF and PJ, the availability of habitats also seems relatively limited, but the forest/hedge environment and the presence of streams give them a higher value. The vicinity of site PB, meanwhile, has the particularity of being partly located on an amphibian reproduction site, that increases its value level, despite the lack of direct observation of high-valued species. The sites PG, PH, and PL have high values due to a high density of aquatic habitats and the observation of a large number of high-value species in their vicinities.

*Birds* Ornithological surveys were conducted using sound recorders and visually with binoculars and cameras. The survey period spanned 2023 and 2024. An inventory was carried out for the 8 surface site locations over several seasons. Five ornithologists took part in the surveys. The inventories were conducted under suitable weather conditions (no rain and little/no wind). Field observations were recorded on-site using computer equipment. Observation intensity varied depending on the seasons. Increased observation intensity was applied to the spring inventories due to the sensitive period for breeding birds. A matrix was established using European guidelines for endangered species that is only applicable to the French territory. For Switzerland, the cantonal and federal protection lists were used to analyse the risks.

Birds find living space in the vicinity of site PA in Ferney-Voltaire, mainly in trees, bushes, and hedges. Some noteworthy species have been found in the vicinity. Birds are also prevalent in the vicinity of the agricultural space in site PB in Presinge and next to the small creeks and rivers. Protected and endangered species were found in the extended zone around the site. Areas and trees in the vicinity of site PD in Nangy provide protection spaces for birds. Some noteworthy species have been found on the surface site location. The surface site PF in Éteaux today includes several bushes that serve birds to find food and rest during the migration. Some noteworthy species have been found on the site. The forest on site PG in Charvonnex and Groisy provides living space for a variety of birds, and the bushes around serve as a retreat and reproduction space. Some noteworthy species have been found in the vicinity of the site. Also the forest on site PH in Cercier and Marlioz provides space for birds. Some heritage species were found on the site. Site PJ is surrounded by bushes and hedges that serve birds as living and reproduction space and for rest during migration. Some heritage species were found on the site and in the immediate vicinity. Also the hedges nearby site PL provide protection for birds and noteworthy species were found there.

<footnote n="9">⁹Environmental issues mentioned here and in the following sections may also be referred to as ‘stakes’ - an alternative translation of the French ‘enjeux’.</footnote>
**Fig. 3.31** European kestrel (*Falco tinnunculus*) observed during field investigations, providing valuable data on local wildlife presence and ecosystem dynamics

<figure><img src="image_164.png" /></figure>

**Fig. 3.32** Red fox (*Vulpes vulpes*) observed during field investigations, providing valuable data on local wildlife presence and ecosystem dynamics

<figure><img src="image_165.png" /></figure>

A full database of species observed was established, and it has been integrated into a project-wide geographical information system. The bird observations have limited validity and must be continued if a decision to advance with a project design is taken.

In summary, the sites PD, PL, and PJ in France, as well as PB in Switzerland and their surroundings, contain hedgerows and open areas that support nesting species of high conservation value. The sites PF, PG, and PH in France feature hedges and forests adjacent to extensive pastures, which are crucial habitats for uncommon species throughout the year. Site PA in France consists primarily of conventional agricultural land that becomes waterlogged in winter, serving as an important stopover site for waders.

To mitigate the environmental impact, dedicated measures will be implemented during the design phase to recreate bird nesting and living areas comparable to those lost, either within the green buffers of the sites or in their immediate vicinity. These efforts will be integrated into rewilding projects associated with the development.

*Mammals* Data on terrestrial mammals was collected during all naturalist assessments of other groups on the surface sites. Therefore, data on terrestrial mammals were collected both day and night at all surface sites throughout four seasons. Terrestrial mammal species were recorded visually or through indicators such as tracks, faeces, burrows, etc. The particular attention given to weather conditions for other groups was also applied during the assessments of terrestrial mammals. All observations were geolocalised and recorded in the project-wide geographical information system.

The PA site in Ferney-Voltaire has been the subject of infrequent observations of terrestrial mammals during naturalist investigations. They include the European roe deer, wild boar, European badger, European hare, brown rat, and greater white-toothed shrew. In the wider surrounding bibliographic data also revealed the presence of species of medium concern, such as for instance the hedgehog and beaver.

In the vicinity of site PB in Presinge, two species with a high conservation priority in Switzerland were observed: the beaver and the hare. Other species with a low priority that were encountered are the roe deer, badger and fox.
<figure><img src="image_166.png" /><figcaption>**Fig. 3.33** Bat detectors used to detect the presence of bats by converting their echolocation ultrasound signals</figcaption></figure>

Bibliographic data also provided information about species with a very high priority: the harvest mouse, polecat, weasel, wolf and the dormouse. Two species with a medium priority are the hedgehog and the stoat. However, these species were not observed.

The observations on site PD in Nangy of medium importance are the beaver and hedgehog. A species with lower importance, the fox was also observed. Bibliographic data also reports on the wildcat, the polecat, the black rat, but they were not observed.

Several observations have been recorded at the PF site at Éteaux: the hedgehog, with medium importance, and the fox and the badger, with very low importance. Bibliographic data details the presence of four species of medium conservation concern, including the Alpine Ibex, European beaver, European rabbit and the wildcat.

Observations at the PG site in Charvonnex and Groisy ranging from very low to low importance are: European roe deer, fox, squirrel, wild boar, European hare, chamois. In the surroundings, the bibliography also reports species with high importance: European otter, polecat. The following species with medium importance are reported: hedgehog and wildcat. However, these species were not observed.

At the PH site in Cercier and Marlioz the presence of species with medium importance such as the beaver and the squirrel were recorded. Species of lower importance concern the red deer, roe deer, wild boar and fox. The bibliography also mentions the presence of species with very high concern such as the grey wolf, otter and medium concern such as the wildcat and the hedgehog. These species were, however, not confirmed.

At the PJ site in Dingy-en-Vuache and Vulbens several observations of mammals with medium importance were made, such as the European beaver and the wildcat. Species with lower importance are the squirrel and with even lower importance the red deer, roe deer, hare, wild boar, badger, fox and the greater white-toothed shrew. The bibliography also mentions the presence of the lynx and the otter with very high importance and the rabbit with medium importance, but they were not observed.

Observations on site PL in Challex with a very low importance include the badger, fox, roe deer and hare. The analysis of the bibliography highlights four species with medium concern: wildcat, beaver, rabbit, and hedgehog. The polecat is cited with high importance and the lynx with very high importance. These species have, however, not been observed.

Summing up the bibliographic and field investigations of mammals carried out on all surface site candidates and in extended perimeter around the sites shows that overall a strong sensitivity exists for all sites although on none of the sites direct observations of relevant species were confirmed. The reason is that mammals were observed in the vicinities and extended surroundings of the sites and they can traverse the sites today, but they will face limitations during construction periods and when the sites are constructed. However, no protected or endangered species would be affected directly by the surface sites. A subsequent preparatory project phase needs to consider the mammals in the surroundings of the site in the design of the construction sites and the surface sites. Ecological corridors need to be considered and preserved. Where possible, green buffers and sites that can be traversed by mammals can preserve their current behaviour. Embedding the presence of animals in general in the concepts of surface sites can also help to improve their habitats and eventually even support the increase of biodiversity and conditions for them.

*Chiropters* Chiropters (bats) are mammals. The name chiroptera comes from the Greek words their (hand) and pteron (wing), meaning ‘hand-wing’. This reflects the unique structure of their wings, where elongated fingers are covered by a thin membrane of skin that allows them to fly. Chiropters are in the focus of environmental studies due to their ecological importance, vulnerability to habitat changes, and the legal protections they enjoy in France and Switzerland through national laws, as well as in the frame of the EU habitats directive, the ‘EUROBATS’
agreement, the ‘Bern Convention’ and ‘Natura 2000 site’. Violating protections of bats in France can result in significant penalties consisting of high fines and prison sentences.

This study comprised dedicated field investigations applying different techniques which included echolocation detectors (see Fig. 3.33), to establish an inventory of bats on and in the vicinity of candidate surface site locations to permit developing avoidance, reduction, compensation, and accompanying measures during a subsequent project design and preparatory phase.

Bibliographic analysis could unfortunately not be carried out since it requires a detailed description of the areas to be investigated, and the surface site locations were not sufficiently defined at the time of making such inquiries for data, which are time-consuming processes with different data owners. Therefore, indirect (e.g., passive and active acoustic searches with ultrasound detectors and microphones, search for traces) searches were immediately carried out at the larger candidate surface site zones.

On site PA in Ferney-Voltaire, France, the existence of an ecological corridor renders the passing of chiropters likely in a band at the southern end of the surface site and outside that zone. 12 species were recorded in the larger area around the surface site location, in particular in the neighbouring woodlands and groves. There were no sightings on the site itself, probably due to it being an open space currently subject to light pollution during nighttime.

On site PB in Presinge, Switzerland, the zones at the borders of the surface site towards the Nant de Paradis creek represent an area of interest for chiropters for hunting. The same applies for individual bushes, the Seymaz zone and woodlands in the vicinity and garden areas in the Avenir hamlet. 2 species have been observed at houses that would be removed for the construction of the site and 18 species were found in the larger area. 7 of them have a preservation status. This makes the area sensitive and calls for measures to preserve the habitats and avoid and reduce light pollution as far as reasonably possible.

On site PD in Nangy, France, the larger zone is of interest for Chiropters for hunting where bushes, trees and houses exist. 3 species were observed on the site and 8 in the extended investigation area. They have protection status. As with site PB, the larger area is sensitive and calls for measures to preserve the habitats and avoid and reduce additional light pollution as far as reasonably possible.

On site PF in Éteaux, France, the neighbouring areas are of interest for chiropters, in particular zones with hedges and woodland. This concerns for instance the boundaries of the surface site, houses and gardens along the national road and the wetland zones. 13 species were observed on the larger area and some of them on the site close to trees. 3 enjoy a protection status. The larger area represents an interest for this species and calls for measures to preserve the habitats and avoid and reduce additional light pollution as far as reasonably possible.

On site PG in Groisy and Charvonnex, France, the woodland is of interest for chiropters. It extends to the autoroute zone in the north. 18 species have been observed in the larger area and 13 species were found in some locations on the surface site, primarily in the forest. 8 enjoy a protection status. The strong presence of chiropters in the forest calls for a minimisation of the impact on those zones during the design phase and envisages compensation and accompanying measures.

On site PH in Cercier and Marlioz, France, chiropters find hunting areas and a corridor in and between the woodlands. 13 species have been observed within the site perimeter in the woodland. 5 species enjoy a very high protection status and two are highly protected. The density and diversity diminishes as one approaches the road on the eastern side of the site. These findings call for further optimisation of the site, reduction, compensation and accompanying measures in the subsequent phase.

On site PJ in Dingy-en-Vuache and Vulbens, France, the woodlands at the creeks and the hedges at the limits of the surface site are interesting spaces for chiropters. Ten species were found on the border of the site and 16 in the larger area around the site. Some enjoy a particular protection status. The density and diversity are higher around hedges and trees close to the motorway. This location will need some attention during the subsequent site design with respect to avoidance, reduction, compensation and accompanying. Artificial light pollution is one issue to be considered in this area.

On site PL in Challex, France, chiropters find suitable locations in the woods, hedges, hamlets and individual houses, their gardens and the nearby vineyards. Two species with medium to low protection status were recorded at the houses that would have to be removed to construct the surface site.

Summing up, the stakes with respect to chiropters directly on the surface sites are low in PA, PB, PD and PL. PJ has no particular sensitivity on the entire site, but a small sector that is close to the woodlands requires particular attention. The stakes are average for PF, high for PG and very high for PH. The limitations of impacts on chiropters, the preservation and, where possible, the improvement of their habitats have to be included in the eco-design approach to be implemented in the subsequent phase.

*Reptiles* Field investigations on the candidate surface site locations focused on identifying reptile populations (like the wall lizard shown in Fig. 3.34) in environments that are known to be favourable habitats for them. They include for example semi-open areas, forest boundary zones, cavities and stone or woodpiles as well as constructed areas. These inventories were carried out during the reptile’s primary activity periods from May to June and from
<figure><img src="image_167.png" /><figcaption>**Fig. 3.34** Common wall lizard (*Podarcis muralis*) observed during field investigations, providing valuable data on local wildlife presence and ecosystem dynamics</figcaption></figure>

September to October. Each observation was geolocated. No intrusive methods were used to avoid disturbance to the species. Several methodological limitations, an unfavourable rainy spring and an exceptionally hot summer as well as access limitations set limits on the quality and reliability of the results. This concerns mainly the data for snakes that are more difficult to observe than other reptiles. For a preparatory phase project and a comprehensive environmental impact assessment, the initial state of reptiles has to be updated with complementary studies.

The natural habitats investigated for reptiles varied across the sites, leading to different levels of suitability for living spaces and ecological corridors.

At site PA in Ferney-Voltaire, France, the forest edges and wood strips were identified as high-value habitats. Isolated trees and cultivated areas had a lower interest. Only one species with a low conservation value, the common wall lizard, was observed on the annex site south of LHC point 8. Bibliographic data do not indicate the presence of species with high stakes.

At site PB in Presinge, Switzerland, the zones with vegetation at the nearby creek Nant de Paradis, gardens in the Avenir hamlet and small woods in the vicinity are of interest to reptiles, but not the surface site location. Only a single species was found in the larger area around the site. No species were found on the perimeter of the site.

At site PD in Nanxy, France, interesting locations for reptiles are at the southern end of the site in the hedges and the borders of the autoroute, but not the surface site. Three species were found in the larger area around the site and at the extreme edge in the south, outside the site.

At site PF in Éteaux, France, the hedges at the border of the surface site are of interest for reptiles. Only a single species was found in the larger environment around the site. No observations could be confirmed on the site or in the immediate vicinity.

At site PG in Groisy and Charvonnex, France, the forest zone and the limits of the woodlands are of interest for reptiles. Also, areas close to the highway can be relevant spots. 2 species were found in the larger area around the site, but no observations could be confirmed on the site directly.

At site PH in Cercier and Marlioz, France, the entire forest occupied by the surface site location is of interest for reptiles. 2 species were found in the area around the site, sometimes entering the perimeter of the site. However, no clear pattern of presence or movement could be determined that would permit drawing sound conclusions on the permanent presence of reptiles on the site.

At site PJ in Dingy-en-Vuache and Vulbens in France, areas in the vicinity of the creeks, bushes, groves and trees including the zone close to the motorway are of interest for reptiles. 7 species were found in the larger area around the site, leading also to the conclusion that at the edges of the site, species could be present.

At site PL in Challex, France, gardens, bushes, and trees are of interest for reptiles but not the majority of the surface site. Only one species could be found at a distance of the site, close to the forest in the north. No observations on the site could be confirmed.

Summing up, only very low sensitivity with respect to reptiles exists for sites PA, PB, PD and PL. In the vicinity of PF some care needs to be taken to preserve the living spaces of reptiles. For PG and PH sensitivity may exist in some parts of the forest and the project design needs to respect this condition. An update of the initial state with complementary field investigations is required to optimise the integration of the surface site, applying avoidance and reduction measures. The architectural designs of the surface site constructions should integrate concepts that favour the creation of habitats and thus help to increase the presence of reptiles.

*Insects* Bibliographic research and field investigations of the sites and their vicinities by specialised companies were used to identify the issues with respect to insects. Field investigations were carried out for several months
**Fig. 3.35** Butterfly black-veined white (*Aporia crataegi*) observed during field investigations, providing valuable data on local wildlife presence and ecosystem dynamics

<figure><img src="image_168.png" /></figure>

**Fig. 3.36** Golden-ringed dragonfly (*Cordulegaster boltonii*) observed during field investigations, providing valuable data on local wildlife presence and ecosystem dynamics

<figure><img src="image_169.png" /></figure>

during good weather conditions, low wind and during both day and night identifying insects like those in Fig. 3.35, Fig. 3.36 and Fig. 3.37.

Despite the highly urbanised environment, a strong population of insects was observed in the surroundings of site PA in Ferney-Voltaire due to the favourable living and breeding spaces. The site itself, an agricultural area is not subject to a strong presence of insects and thus, therefore, has only a very low sensitivity. The vicinity of the border between France and Switzerland towards the Geneva airport may require the consideration of a cross-border impact since some species observed in this zone outside the site perimeter are protected in Switzerland. Complementary field investigations are required during a project preparatory phase to reveal any such potential case.

The surroundings of site PB in Presinge feature an important population of insects, mainly those relating to aquatic habitats. Some species observed in this area outside the site perimeter enjoy particular protection status in Switzerland. The site itself is an agricultural space with low stakes apart from the areas that are close to the nearby creek.

The surroundings of site PD in Nangy are characterised by a few insect species. The site is an agricultural space and has low stakes with respect to insects. No species with protection status were observed. The extended surroundings of site PF in Éteaux are attractive for insects. However, on the site and in the immediate vicinity, no relevant species were identified, and the sensitivity is low.

The forest at and around site PG in Charvonnex and Groisy is moderately attractive for insects, as are the surrounding hedges. The site itself does not show particular issues with respect to insects. Also, the woodland spaces did not reveal the presence of relevant insects.

The forest spaces at and around site PH in Cercier and Marlioz provide, in principle, a favourable habitat for insects. However, only little presence of insects was revealed within the candidate site perimeter. Due to some observations at the border of the site, the site has a medium level sensitivity.
**Fig. 3.37** Italian locust (*Calliptamus italicus*) observed during field investigations, providing valuable data on local wildlife presence and ecosystem dynamics

<figure><img src="image_170.png" /></figure>

**Fig. 3.38** Stream photographed during the field investigations

<figure><img src="image_171.png" /></figure>

Site PJ in Dingy-en-Vuache and Vulbens, in principle, offers favourable conditions due to the trees and hedges around it. The stakes are high in the extended surroundings, but they are low on the site itself.

The hedges and bushes around site PL in Challex also, in principle, provide a favourable habitat for insects. However, the site shows only low-level issues with respect to insects, though a presence cannot be entirely excluded. Some species are protected in the nearby Swiss territory. A preparatory project phase will have to make complementary field investigations to consider potential cross-border impacts.

Summing up, none of the surface site candidates exhibits particular sensitivity with respect to insect presence. The surroundings of site PB present a habitat with high sensitivity. The wider surroundings of site PF present, in principle, some sensitivity. For sites PG and PH, despite being woodland, the favourable habitat for insects turns out to be less favourable than expected. The presence of some relevant species in the surroundings raises the sensitivity of the areas that are in the vicinity of the site. There were observations of some species with medium sensitivity in the surroundings of site PJ, suggesting that they might also be present on the site.

*Aquatic* Fauna in the aquatic context has been analysed based on cartographic and orthophoto information. Systematic investigations and water analysis for all aquatic aspects were not carried out at this stage. They are planned to be done if a design phase is launched. However, nearby surface water, like the stream in Fig. 3.38, in
<figure><img src="image_172.png" /><figcaption>**Fig. 3.39** Trees in the woodland photographed during the field investigations</figcaption></figure>

the vicinity of sites PF, PG, PH and PJ was analysed. The stake concerning macroinvertebrates is often high in the extended surroundings around surface sites. Aquatic benthic macroinvertebrates are insects in their nymph and larval stages, snails, worms, crayfish, and clams that spend at least part of their lives in water. Fireflies are another important species that are sometimes encountered in the wider perimeters of the sites.

Although the site PA and its immediate surroundings are not subject to aquatic fauna presence, the wider environment is known to be a habitat for vulnerable and endangered species. Protected and endangered species are close to site PB, although the site does not affect their habitats. Sites PD and PF and their surroundings are not concerned by aquatic fauna. The vicinity of site PG is characterised by important aquatic habitats with vulnerable and endangered species that the project will avoid and aim not to affect. The site perimeter has already been adjusted as a result of various stakes identified during the initial state analysis. Although site PH lies in the forest and close to a creek the presence of noteworthy aquatic species is low and the site itself is not affected. Sites PJ and PL and their surroundings also have no issues with respect to aquatic fauna.

Summing up, the PJ site does not present any observations of benthic macroinvertebrates. The wider surroundings of the PD, PF, and PL sites show a few habitats favourable to the development of benthic macroinvertebrates, but only a few taxa are present. Also, the PH site does not present any taxa with significance; however, the habitats are varied and the taxonomic diversity is high near the site, although with very low significance. The PG site hosts taxa with ‘medium’ significance, but the habitats are varied and taxonomic diversity is high near the site border. The wider PA site surroundings are subject to an observation with ‘high’ significance, but the habitats are poor and have little interest for the benthic macrofauna. The PB wider site surroundings have several observations of taxa with ‘very high’ significance. No surface site has any relation with fish although some sites (PB, PF, PG, PH, PJ) are in the vicinity of small creeks.

*Forest* During this study, expert companies and forest evaluation consultants have made a comprehensive and detailed forest quality and value analysis. This included the potential loss of biodiversity, habitat and economic income over a sustained period of several decades. The results are also integrated into the comprehensive, wider socio-economic assessment. The French ‘Indice de biodiversité potentielle’ (IBP) methodology was applied [86, 87]. The project will not affect any existing forest spaces in Switzerland. Forests like the woodland shown in Fig. 3.39 are in the vicinities of sites PA, PB, PD, PF, PG, PJ and PL. Only sites PG and PH will require clearings.

The forest that would be affected by site PG has quite a diverse character. The xeric woodlands located in the southeast mainly consist of small-diameter oak woods, showing a strong to weak stake depending on the area. The ravine woodlands in the west feature a composition of large and very large trees rich in dendro-microhabitats, potentially hosting a rich and diverse biodiversity. The central area of the forest presents a character more easily exploitable for forest owners. This leads to more or less diverse stands depending on the plots. The presence of large dead wood is less important overall. The challenge in terms of biodiversity varies from strong to weak depending on the age of the trees. Consequently, the surface site has been adapted to reduce the affected forest as much as possible and to select an area for the access shaft locations that has a lower quality than the surroundings. In total about 2.4 ha of forest may be affected by the surface site development.

The forest at PH features relatively young woodlands resulting from agricultural abandonment, thereby having few dendro-microhabitats. The woodlands located on the northern fringe of the site are the oldest and there is presence of a temporary watercourse. Medium wood is less conducive to supporting forest biodiversity than large and very large wood. In total, up to 10 ha of forest may be affected in the communes of Cercier and Marlioz. Further surface site designs are needed to determine the exact surface requirements, taking into consideration all the environmental issues that have been identified.

*Summary* Detailed data are included in specific paragraphs of the biodiversity section. To the east of the PA are wetlands that serve as a migratory stopover for bird species, and to the south, near LHCb Pt8, is a forest of
ecological value due to the presence of bats and insects. Some agricultural patches near the site with isolated trees also play a valuable role for birds. The PA surface sites have low ecological stakes, however the future construction must carefully consider the surrounding elements to maintain the key habitats and species.

The PB surface site presents low to moderate ecological stakes, however the presence of diverse bird species, aquatic insects and protected plants along the Nant du Paradis stream highlights the ecological value of the site's nearby areas. The future construction must take into account the ecological sensitivity of these places to ensure the preservation of biodiversity and habitats.

The site PD is entirely covered by agricultural land which represents low-level stakes. Small areas of high ecological importance are located further north of the site. These include hedges and old trees that provide habitat for birds and bats of low or moderate concern. Future construction in this area has to take into consideration small fauna species that might be present on or crossing the site.

The PF site is used as an agricultural meadow and presents moderate ecological states. However, the site is located within the ecological corridor for wildlife movement, near the wetland area and forest with the stream providing habitats for a range of species, including birds, bats, and amphibians. The site layout must be carefully planned to avoid disrupting the sensitive ecosystems and ensure good functionality of the fauna corridor.

The main PG surface site is partly in a forest area, which represents high stakes, and partly in pasture land with low stakes. The annex site to the north, located near the highway, shows low ecological stakes. The main constraint rPG site is the valuable forests that hosts fauna and flora species, therefore the effort has to be put into limiting deforestation and maintaining the current habitats.

The PH surface site is located in the forest with small clearings and wetland area. Part of the PF surface site shows very high stakes, mainly in the north, due to the presence of bird species, including those of high conservation concern, bat species with their ecological corridor as well as small fauna. Stakes of strong character, with parts of medium and low are located in the southwestern part of the site. Limiting the use of areas with high stakes will be necessary to preserve its biodiversity and ecological value.

Most of the PJ surface site presents low stakes, excluding an inventoried small wetland and hedgerow that are considered as strong stake. The current layout of the site already foresees the space for an ecological corridor and grassy meadows in order to maintain connectivity between natural areas for wildlife and to keep areas for birds to hunt.

The major part of the PL surface site is located on the agricultural land presenting low stakes. Some hedges within the site and in the vicinity of the site play an important role for bird species and must be preserved whenever possible.

To ensure responsible development of the areas, site construction must be carefully planned to minimise habitat disturbance, maintain ecological corridors, and preserve biodiversity. By integrating these considerations into project design plans at the early stage, it is possible to balance infrastructure needs with the preservation of local biodiversity and ecological integrity.

### 3.3.6 Ecological functionality

In France, the ecological network, known as the ‘Trame verte et bleue’ (Green and Blue Framework), is a component of the national and regional planning framework. It integrates terrestrial and aquatic ecological continuity. This network comprises biodiversity reservoirs, ecological corridors, permeable terrestrial and aquatic spaces, and large agricultural areas. These elements collectively support species movement, lifecycle completion, and biodiversity preservation. In Switzerland, the ecological network identifies essential zones for nature and their connections. The REN’s (Réseau écologique national) framework includes nodal zones (vital habitats for species lifecycle completion), extension zones (lower-quality or smaller zones), continua (interconnected areas such as forests and wetlands), and development zones (partial habitats). The network also features ecological corridors linking key areas.

The difference in both countries lies in implementation and structure. In France, the ecological network emphasises integrating green and blue corridors at a national scale under regional governance. In contrast, Switzerland’s REN adopts a more localised approach, focusing on specific ecological zones and their physical connectivity. Additionally, the French framework includes significant agricultural spaces and functions of water bodies while the Swiss REN categorises its zones with a greater focus on inter-zonal ecological dynamics.

The site PA and nearby area are permeable agricultural spaces that represent only limited interest in terms of ecological functionality. A regionally important ecological corridor was identified south of the surface site. Wetlands in the vicinity of the surface site contribute to the ecological functionality in the context of the blue network. According to the local urban development plan, three isolated trees located to the east of the main surface site and trees to the south-east are considered a landscape element to be preserved. The layout and design of the surface site constructions will need to ensure that the ecological continuity is maintained.

Site PB is located on large agricultural land with some extensive areas and a continuum of dry grasslands. However, these areas which are conducive to biodiversity are not located within the surface site. There are two locally important movement corridors for large fauna, one of which passes west to the surface site without crossing
it and the other through the eastern part of the surface site area, near the hedgerows, which should be taken into account in the design phase. The PB surface site lies in the immediate vicinity of the blue continuum, which follows the hedgerow line to the north-east. However, the location of the site does not directly interrupt the functionality of this network.

The area of PD surface site is located on the permeable relay agricultural land. South of the PD surface, under RD903, a secondary corridor of medium fauna that is to be considered in the design phase was identified. The surface site does not encroach on any element related to wetlands or water areas and therefore does not affect the functionality of the region's blue network. According to the Nangy local urban plan, no element of biodiversity reservoirs or ecological corridors is present in the study area.

The PF surface site is located within permeable agricultural spaces and a forest ecological corridor connecting the areas located to the north-west and south-west of the site. It is a remote area used by large fauna. The surface site is close to two wetland areas of the blue network, the functionality of which has not yet been analysed. This aspect must be taken into account in the design phase of the surface site. It will also be necessary to ensure the functionality of ecological corridors and large fauna movement routes between the forest areas to the north and south of the site surface, as required by the Éteaux commune's local urban plan.

To the north of the PG surface site, across the highway, there are two forested corridors, while to the south there is a linear corridor, also forested. The PG area with its annex is located in permeable spaces, partly on agricultural and forest land, however the PG surface area is not located in any ecological corridor and no biodiversity reservoir has been inventoried. The surface site does not concern any element of the blue network. According to the Groisy local urban plan, the surface site and the possible access road are located on classified forested areas - Espaces Boisés Classés - which results in preservation or appropriate reforestation in the case of felling, depending on the agreed compensation method, therefore construction in the forested area will be limited to the minimum necessary.

The PH surface site is concerned only with permeable relay spaces and does not cross any ecological corridors or biodiversity reservoirs. The surface site's proximity to the Tabassé stream, which joins the Usses watercourse, is one of the main elements of the blue network of the area. During the field visits, the wetland was inventoried on the perimeter of the surface site, but it does not seem to represent a major functional role in the blue structure. The local urban development plan of Val des Usses and Cercier also mentions a sector of ecological interest related to the watercourse to the north, which will be taken into account when designing the layout of the infrastructure.

The PJ surface site is located on agricultural land with permeable relay spaces, as well as an ecological corridor connecting forested biodiversity reservoirs between the north and the south, which connects with another ecological corridor in the further part. There are two small streams, west and east of the PJ site, and a wetland has been inventoried on the site itself, but its functionality has not yet been analysed. In accordance with the local urban plans of two municipalities concerned, the surface site is located between wooded area ensuring the ecological continuity, and contains two lines of protected hedges. The preservation of ecological continuity and the ecological corridor will be taken into account during the design phase.

The PL surface site is located on the relay permeable spaces and agricultural spaces. A regional wetland from departmental inventories and a corridor for the movement of large fauna are located to the north of the site, however, these structures do not cross the site. According to the local urban plan of the municipality of Challex, small hedges that are within the surface site perimeter and in close vicinity are considered natural structures and are to be preserved for ecological reasons.

In summary, the PA site includes a regional ecological corridor with wetlands and hedges that need preservation to maintain ecological continuity. The PB site is near two fauna movement corridors and the blue network along the eastern side. Though the site does not directly impact the blue structure, the surface site layout has to take it into consideration. The PD site consists of agricultural spaces with a secondary fauna corridor in the south, near the RD903 but does not encroach on wetlands or biodiversity reservoirs. The PF site is located near two wetlands and within an ecological corridor, which will have to be taken into account in the design phase. Part of the PG site includes a classified forest area, and wood cutting should be minimised. The design of the site will have to ensure that the functionality of nearby ecological corridor and biodiversity reservoir is maintained. The PH site is close to the stream, and a larger watercourse is to be considered during the layout design. It also has some wetlands present but these play a minor functional role. The PJ site lies in a large ecological corridor, including an area of wetlands and hedgerows of ecological value. Lastly, the PL site consists of agricultural land with hedges that need preservation, while a regional wetland and fauna corridor further to the north remains unaffected. Overall, ecological continuity and protected elements must be carefully considered during the design phase to ensure their functionality.

### 3.3.7 Urbanism

The urbanism aspects comprise all local and regional policies and plans for territorial developments. All land plots are subject to such plans, and they are regularly reviewed and updated at the municipality level and at the local and regional public administration levels.
<table><caption>**Table 3.12** Summary of urbanism issues</caption><thead><tr><td>Topic</td><td>Extended perimeter around site</td><td>Description of stakes</td></tr></thead><tbody><tr><td>Strong urbanism stakes</td><td>PA, PB, PD, PF, PG, PH, PJ, PL</td><td>Nature and agriculture protection zones, humid zones.</td></tr><tr><td>Other urbanism stakes</td><td>PA, PB, PD, PF, PG, PJ, PL</td><td>Protected or valuable architecture in the vicinity, sport facilities, agriculture, roads, highways.</td></tr><tr><td>Public utility servitude</td><td>PB, PF, PH</td><td>Pipelines, electricity lines and protection buffers around those infrastructures.</td></tr><tr><td>Urban environment and applicable regulations</td><td>PA, PB, PD, PG, PF, PJ, PL</td><td>Co-visibility, requirement for integration in the urban context, topographic constraints.</td></tr></tbody></table>

<table><caption>**Table 3.13** Summary of urbanism topics by site</caption><thead><tr><td>Site</td><td>Stakes</td><td>Urbanism topics</td></tr></thead><tbody><tr><td>PA</td><td>High</td><td>Protected agriculture zone, gas pipeline at the site border</td></tr><tr><td>PB</td><td>High</td><td>Protected agriculture zone (SDA), ecological corridor, landscape integration</td></tr><tr><td>PD</td><td>Low</td><td>Agricultural space, road development project</td></tr><tr><td>PF</td><td>Low</td><td>Agricultural space</td></tr><tr><td>PG</td><td>Low</td><td>Agricultural space, nature zone (forest)</td></tr><tr><td>PH</td><td>High</td><td>Agricultural space, nature zone (forest), pipeline at the northern site limit</td></tr><tr><td>PJ</td><td>High</td><td>Agricultural zone, wetland zone, protected agricultural space, ecological corridor</td></tr><tr><td>PL</td><td>Medium</td><td>Protected agricultural zone, nature protection zone</td></tr></tbody></table>

The urban aspects of the perimeters of the surface sites, enlarged and extended zones of several kilometres around the surface sites have been analysed based on the relevant regional and local urban plans in France and in Switzerland. In addition, field visits permitted the publicly available information to be complemented and enriched with the up-to-date situation. This survey permits all regulatory constraints with respect to the territorial development to be compiled and anticipating the planned evolution of the territory from an environmental point of view, considering all of the applicable laws and regulations. The relevant documents and associated geographical information systems and maps comprise PLU, PLUi, PLUIh, PADD, SCoT in France and PDCn and PDCm of the canton in Geneva in Switzerland.

Table 3.12 shows that all extended or enlarged perimeters around the surface sites are subject to strong or other urbanistic and territorial development issues. These issues have to be taken into account during the detailed project plan development.

Table 3.13 shows that half of the sites are directly affected by urban constraints that need to be considered during the site design development and that require particular attention during the project authorisation process.

### 3.3.8 Mobility

Data about the public transport infrastructures and road traffic as well as soft mobility and multi-modal mobility within the perimeter of the project have been collected and analysed. Figure 3.40 presents a schematic representation of the travel flows in Grand Genève.

**Public transport** The PA Site is well served by the Geneva public transport system (TPG) which operates across the Swiss/French border and serves the entire zone. The bus connection is direct, and there is a tramway connection within a reasonable distance. Site PB in Switzerland is also served by the TPG network with a bus station in the immediate vicinity and a tramway connection at a reasonable distance. The PD Site in France is well served by regional French bus lines, including a park+ride facility connecting to Geneva. The presence of the large hospital (CHAL) ensures that the connections are maintained and potentially further developed. The location of site PF is poorly served by public transport. However, 2 km away, La Roche-sur-Foron train station is an important multi-modal transport pole including a connection to Geneva via the Léman Express. The PG site is not served by public transport. However, the Groisy train station is 2 km away and provides regular connections to Annecy and Geneva via the Léman Express line. The PH site is not served by public transport and no public transport exists in the vicinity. Site PJ is not served by public transport, but 2 km away, a Swiss TPG bus line connects to Vulbens
<figure><img src="image_173.png" /><figcaption>**Fig. 3.40** Daily travel flows (all modes combined) in Grand Geneve (Source Grand-Genève [88], based on MRMT – EDGT 2015 - 2016) Although Geneva remains a central hub, the analysis of flows reveals a more multipolar organisation, with a majority of internal travel within the large territories (Geneva, French Geneva, Nyon district)</figcaption></figure>

and in Valleiry, there is a train station on the line between Bellegarde and Evian via Annemasse. Although there are Swiss TPG bus stops in Challex in the vicinity of site PL, the frequency is modest. Better connections exist in nearby Dardagny in Switzerland. At a distance of 4 km in La Pleine, there are very good connections to bus and train lines.

Summing up, the experiment sites PA and PD are well served by public transport and the experiment sites PG and PJ are reasonably connected at some distance. The technical sites PB, PF, PH and PL are not well served by public transport. An analysis of the demand from these sites would be required if further development of the public transport system is considered in relation to the FCC project. It could be in the mutual interest of the project and the local stakeholders to develop public transport around the PG and PJ experiment sites at least.

**Road network** The experiment sites PA, PD, PG and PJ are in the immediate vicinity of major roads and would profit from direct access to the autoroute infrastructure for construction and installation purposes. This would eliminate any potential residual local traffic challenges around the sites during these phases. The PA site is also well-connected to the CERN Prévessin and Meyrin sites via a major departmental road. In addition, the PL technical site is in the vicinity of a major departmental road and is also well-connected to the existing CERN sites. The PB Site is directly on a good road, but the traffic situation through Geneva and to nearby Annemasse in France is challenging. Technical site PF is also well-connected via a major departmental road. Although site PH is directly located on a departmental road, it is isolated and is distant from major transport routes. The closest autoroute access is at a distance of 10 km in Allonzier-la-Caille. Installation of bulky equipment at this site needs to be carefully studied, developed and planned.

**Other transport modes** The study also included the analysis of dedicated bicycle tracks in France and Switzerland. Dedicated lanes and tracks have recently been constructed in the vicinity of site PA and these are expected to
<figure><img src="image_174.png" /><figcaption>**Fig. 3.41** Current and potential future extension of the Leman Express</figcaption></figure>

be further developed. These spans the Franco-Swiss border. A dedicated bicycle track is also being constructed directly at the PB site. Sites PD and PF are not equipped for soft mobility. No dedicated bicycle lanes exist around site PG, but the road to Groisy is well-adapted for cyclists. Site PH has no soft mobility infrastructures. The surroundings of site PJ are being developed with a view to strengthening soft mobility, aiming to link the nearby municipalities Vulbens and Valleiry. The creation of access to site PJ also permits the connection of Dingy-en-Vuache to this system. PL is not particularly equipped for soft mobility. Although walking and biking are easy in the commune, there are no dedicated links to other municipalities in France and Switzerland.

*Foreseeable evolution* The Grand Genève area is developing a multi-modal transport plan that aims to improve further the transport infrastructure across the Franco/Swiss border. The continued housing development and demographic evolution of about +1.2% per year in the neighbouring French departments of Ain and Haute-Savoie, which is unrelated to CERN's activities, calls for such developments. There are about 1.2 million journeys today within the perimeter of the project, but about 4.2 million per day are expected by 2040. As will be described later, the activities relating to the construction, installation, and operation of the project are insignificant compared to the existing and future mobility in the region.

The extension of the Swiss railway system continues to increase its daily train capacity, mainly due to the Léman Express lines (see Fig. 3.41). This also includes an improvement of the services to the Arve valley (La Roche-sur-Forton), Groisy and Annecy for completion in 2030. In the longer term, developments are planned for increasing the service to La Plaine and beyond to Bellegarde. Autoroute extension projects in Switzerland have been planned, but were recently put on hold. A project to connect both sides of Lake Geneva sides by a tunnel under the lake has been studied, but any potential implementation before 2050 is unlikely and therefore the project is not included in specific plans. In France, an autoroute is planned to connect the A40 (Arve valley) to the A412(Thônon) via a wide departmental road (RD903) connecting to the A40 in Nangy. Bus line developments between major agglomerations and the hospital next to the PD site are likely.

*Project induced traffic* Project induced traffic refers to the following types:

1. Workers commuting to and from the construction sites during an approximately ten-year-long construction phase.
2. Evacuation of excavated materials from construction sites. While all sites require the evacuation of materials during the first two years, only four sites will see relevant transport of excavated materials during another 6 to 8 years due to the deployment of tunnel boring machines.

3. Transport construction materials to the construction sites. All sites will see a moderate inflow of construction materials during the first two years, but only four sites will continue to have relevant construction materials inflow during the period when the tunnel boring machines are deployed. Construction materials also need to be brought in when the surface site buildings are constructed.

4. Transport of accelerator equipment during the six to eight-year installation phase that overlaps partially with the civil construction activities.

5. Transport of the experiment detector equipment during experiment installation that overlaps with accelerator installation and testing phases.

6. Commute of engineers and scientists during the installation and testing phases.

7. Commute of engineers and scientists during the operation phase.

8. Commute of engineers and scientists during regular maintenance periods and in the frame of repair activities.

9. Traffic induced by visitors to experiment sites during the operation and shutdown phases.

The main project-induced traffic is linked to the evacuation of the excavated materials. It will be confined to major transport routes. The inflow of construction materials represents a minor additional contribution to this traffic. Commute of workers is intended to be organised centrally, as is best practice for construction sites. The installation of equipment for the particle accelerator represents a minimal contribution to the traffic. The same is true for the transport of the experiment detector equipment. For this case, some isolated, exceptional loads may be required due to the size of pieces manufactured off-site. Once operational, only a few scientists and engineers commute daily to experiment sites. Technical sites are predominantly operated remotely and will see very little traffic for maintenance and repair. The traffic of an estimated total number of 25,000 visitors per year to an experiment site during the operation phase can be compared to the traffic induced by a typical museum or archaeological site such as the Grottes de Cerdon in the region (about 50,000 visitors per year<fnref n="10" />) or the Château Voltaire in Ferney-Voltare (about 50,000 visitors per year [89]<fnref n="11" />). This traffic of individual visitors can be managed with appropriate directions to the site and through support by public transport. Visitors in groups arrive in buses, presenting a minimal amount of additional traffic.

More information about the quantities and the additional traffic induced can be found in sections Sect. 2.7.2 and Sect. 2.7.12. A first quantitative traffic analysis has been carried out to confirm that the traffic is manageable and that with respect to the nearby major transport routes, it represents only a minor addition.

### 3.3.9 Human activities

**Human activities** The analysis of the environmental state established the situation concerning human activities around the surface sites. The environment around site PA in Ferney-Voltaire is dominated by commercial activities (like the commercial centre shown in Fig. 3.42), the LHC Pt8 surface sites and the airport. The presence of a surface site does not add to these activities. The environment around PB in Presinge is rural and characterised by small hamlets. The Geneva Landscape and Architecture School (HEPIA) is an academic activity zone in the vicinity. Towards the west, the zone starts to be dominated by urban activities. The environment of site PD in Nangy is characterised by a mix of agricultural, commercial and industrial activities, residential zones and a major hospital (CHAL). Due to this mixed environment and the major transport routes available, the location is advantageous for an experiment site with a permanent presence of scientists and engineers. PF in Éteaux is located on a main transport route with dispersed residential areas, small businesses and artisans and a major public works company opposite the site. PG in Groisy and Charvonnex does not have major human activities. The vicinity of Groisy, with schools and potential for local development, is an opportunity to develop a main experiment site with the presence of scientists and engineers. Site PH in Cercier is very rural, with agricultural activities (fruit production) and some small hamlets. No major human activities are carried out in this area. The environment around the PJ site in Dingy-en-Vuache and Vulbens is agricultural with commercial activities to the north-east in Valleiry. PL in Challex is in an agricultural zone with low-density residential areas. Commercial activities take place at a distance in La Plaine, Switzerland, which is not directly linked to the site.

**Population** The population density around the eight surface sites varies significantly. Around PA, the area is moderately populated with about 34,000 inhabitants within a perimeter of 2 km. The major communes are Ferney-Voltaire, Prévessin-Moens in France, Meyrin and Grand-Saconnex in Switzerland. The population growth

<footnote n="10">¹⁰https://www.ain.cci.fr/sites/g/files/mwbcuj1466/files/2024-02/Chiffres%20cles%202024%20AIN_.pdf.</footnote>

<footnote n="11">¹¹https://www.lemanbleu.ch/fr/Actualite/Archives/Le-chateau-de-Voltaire-entierement-renove.html.</footnote>
<figure><img src="image_175.png" /><figcaption>**Fig. 3.43** Residential district photographed during the field investigations</figcaption></figure>

<figure><img src="image_176.png" /></figure>

in this area is 2.4% per year but this is unrelated to CERN's activities. Around PB the environment is sparsely populated, at most 6000 inhabitants can be counted in a perimeter of 2 km. The main communes are Presinge, Pupling, Choulex, Meinier, Jussy in Switzerland and Ville-La-Grand in France. There is no annual population growth in Switzerland (between −0.3 and +0.3%). In neighbouring France, the annual growth is modest (+1.1%), comparable to the average in Haute-Savoie. Site PD is located in a moderately dense environment with about 4000 inhabitants in a perimeter of 2 km, the majority located in Nangy and Contamine-sur-Arve and Fillinges. The annual population growths in these communes are highly diverse, ranging from negative 0.5% in Nangy to +3% in Contamine-sur-Arve. The PF site is located in a moderately populated zone with about 4000 inhabitants in a 2 km radius with the majority of people in Éteaux and La Roche-sur-Foron. The population evolution is stable, ranging between −0.6% and +1.0% per year. PG is located in a sparsely populated area with around 4000 inhabitants in a perimeter of 2 km, mainly in Charvonnex and Groisy. However, the two communes see an annual population growth of between 2.2 and 3.2%. The environment around the PH site is very weakly populated. There are only 1500 inhabitants in a perimeter of 2 km in Cercier, Choisy and Marlioz. The population growth is around 1.5% per year. The area around PJ is also sparsely populated with about 6000 inhabitants in a perimeter of 2 km in Vulbens and Dingy-en-Vuache. Valleiry is a more densely populated commune nearby. The annual population growth is 2 to 3.5%, higher than the average in Haute-Savoie. PL in Challex is in a sparsely populated area with only about 3000 inhabitants in a perimeter of 2 km including Challex in France and Dardagny in Switzerland. Both communes experience an annual population growth of about 3% per year.

**Housing** As with the population, the housing situation also varies significantly amongst the surface site areas. In the immediate environment around PA, the housing sector is dominated by apartment buildings (like those shown in Fig. 3.43). Prévessin is dominated by individual houses. The housing sector around PB is mixed with individual houses in the closer vicinity and residential buildings further away. The communes in the vicinity of the site are not dominated by individual houses, but see a mix of houses and residential buildings. The area around PD is dominated by individual houses. Individual houses are also predominantly found around site PF. The entire area around PG is dominated by individual houses, as is the case with sites PH and PJ. Only Valleiry is an exception with a significant number of residential buildings and apartments. The surroundings of site PL have a highly contrasting housing sector. Mainly individual houses are found in the French communes of Challex, Péron, Saint-Jean-de-Gonville. Residential buildings are predominant in the Swiss communes of Avully and Dardagny.
<figure><img src="image_177.png" /><figcaption>**Fig. 3.44** Overview of the employment opportunities in the perimeter of the FCC reference scenario</figcaption></figure>

**Employment** At a general level, the employment sector in the northern sectors of the FCC is dominated by Geneva and its surroundings on French territory (see also Fig. 3.44). The southern zone in Haute-Savoie is characterised by significantly fewer job opportunities and an overcapacity of available workforce. Depending on the region, the tertiary sector is only weakly developed. The secondary sector (industrial activities) offers opportunities in selected locations. Like Geneva, the Department of Ain in France has many more employment opportunities than the Haute-Savoie department.

Around PA, employment opportunities are mainly found in the tertiary sector. In the Swiss territory, the secondary (industrial) sector is also a major source of employment opportunities. Employment around PB is dominated by the primary sector (agriculture) and there is a slightly smaller number of job opportunities than people seeking work. PD has employment opportunities in the industrial sector and the health sector (CHAL hospital), although the job opportunities are limited. The area around PF offers few employment opportunities and those that exist are distributed between the secondary and tertiary sectors. The primary sector (agriculture) is rather weak in this area. There are fewer job offers than the available workforce. Also around PG there are fewer job opportunities than available workforce. In particular, the tertiary sector is only weakly developed. The same is true for site PH in which the primary sector (agriculture) is the main employer for almost one-third of the population. Also the area around PJ sees more job seekers than job offers. The main employment sector is agriculture. Around PL the situation is mixed: residents find their employment in France and in Switzerland.

**Agriculture** The area used for agriculture in the Pays de Gex (e.g., Fig. 3.45) between the site PL in Challex and PA in Ferney-Voltaire has been stable over the last 30 years. The evolution of plot ownership and agricultural exploitations in the 1990s led to fewer but larger farms. The typical size of a single exploitation today is about 90 ha per farm, covering a total of about 3600 ha. The main product remains milk, although this sector is decreasing. Cereals represent a minor contribution. Free trade zones between France and Switzerland in this sector facilitate goods exchange, from which the sector for milk and milk-derived products profits mainly. Out of the 23 million litres produced in the Pays de Gex, 14 million are sold to cooperatives in Geneva. The volume of the milk production in the area is larger than the entire volume in Switzerland. The cereals produced by about 90 producers are almost entirely sold in Switzerland. The production of cereals saw a constant increase with a growth of more than 60% between 2000 and 2010.

Milk production is also an important agricultural sector in Haute-Savoie. Major, globally acting firms and groups (e.g., Société Laitière des Hauts de Savoie / Lactalis) are important economic players in the region who
<figure><img src="image_178.png" /><figcaption>**Fig. 3.45** Agricultural land photographed during the field investigations</figcaption></figure>

also produce milk derived products, in particular Reblochon and Abondance cheese. Green spaces for feeding the cattle are important for this industry. Growing urbanisation puts this branch of the economy under pressure, although the economic potential is high. Production and sales of hay as cattle food is a related main economic branch.

The agriculture sector around PB in Switzerland is dominated by the production of cereals. Recently, following the construction of glass houses, different types of agriculture are fostering the local production of various products. Local agriculture is one of the economic pillars of the canton, although the sizes of the individual operators are much smaller than in France (typically less than 50 ha). Vineyards are another relevant part of the cantonal agricultural sector. Land consumption creates pressure on the agricultural sector: about 20 ha of agricultural space is lost every year.

The sector around PD in Haute-Savoie experiences different climatic conditions than the northern sector. The countryside is more mountainous and the agricultural activities are more diversified, although the main product is hay and grass related to milk production. Almost 5000 ha are exploited in this area for milk and cheese production. 17 million litres of milk are processed by a firm in Fillinges alone.

Moving further south (sites PF and PG) shows that the importance of agricultural activities has decreased over recent decades and small farms dominate. The activities are diverse, including cereals, cattle farming, meat production, hay production, vegetables, poultry and some local wine production. Dairy production remains the dominant branch.

Towards the south-east (PH) the activities are still milk and cheese production with a total area of more than 12,000 ha devoted to it. Other important activities are fruit (apples and pears) and cereals (including maize) production. The entire zone processes per year about 45 million litres of milk. The eastern sector (PD) processes about 12 million litres of milk yearly and also sees dairy product industries (e.g., Baiko). Cattle farming for meat production is a related activity in the sector.

**Forestry** Forestry is mainly important in the French Haute-Savoie department. About 150,000 ha are utilised in the area. 70% of the forests are privately owned. Wood production comprises a variety of different tree types, both deciduous and conifer trees. Forestry in the French department of Ain is also well-developed, mainly supplying wood for carpentry and construction works.

The project scenario only affects forestry in a very limited way in PG (Groisy) and PH (Cercier and Marlioz) in the Haute-Savoie department in France. The economic loss has been quantified, and the potential effects on habitat and biodiversity have been analysed. Mitigation measures can be developed in a subsequent design phase based on this analysis.

**Viticulture** Vineyards (like the one shown in Fig. 3.46) are present in the Ain and Haute-Savoie departments in France, as well as in the canton of Geneva. However, the implementation scenario does not affect any of them. Wine production exists in the vicinity of the PL site in Challex, on both the French and Swiss sides. Wine production also exists at some distance from the surface site PB in Switzerland.

**Tourism** Tourism is already a major economic factor in Geneva and the immediate vicinity of CERN because of its Science Gateway visitor centre and the numerous exhibitions and guided tours that CERN offers. Every year more than 400,000 people visit CERN either individually or as part of groups. The economic impact due to local spending
<figure><img src="image_179.png" /><figcaption>**Fig. 3.46** Vineyards
photographed during the
field investigations</figcaption></figure>

that creates indirect, direct and induced jobs is significant, since people typically combine their visit with other activities in the region, on average for a stay of four days. For instance Ferney-Voltaire (PA site) is known for the Château Voltiare, its typical weekly market and numerous tourist attractions in the immediate vicinity (e.g., the Jura mountains in France and Coppet and Nyon in Switzerland). Geneva and its numerous tourist attractions are not exhaustively listed here. However, the United Nations, the International Red Cross Organisation, the old town, the Jet d'Eau, the watch museums, the cathedral are some examples. The economic benefits in this area today have been recorded and estimations for the effects to be expected with a future collider projects have been estimated and are reported in the section on socio-economic impact (see Section sustainability:results). With the increase of CERN's activities in the region, high-quality science tourism is expected to expand into the Haute-Savoie region, contributing to the tourism development there as well.

Concerning the new sites, PB in Presinge features a number of small, but relevant, tourist attractions that invite pedestrian and bicycle tourists, extending their excursions through the vineyards to the lake or towards France to the Arve valley.

The area around the PD site in Nanpy in France is mostly known for its bicycle tracks that will be significantly extended by 2030. A track from the lake to Mont-Blanc is planned.

The surroundings of the PF site in Éteaux do not yet feature dedicated tourist attractions. However, several opportunities exist for discovering local cheese products between sites PD and PF. Together with a visitor centre at PG in Charvonnex and Groisy the entire zone could profit from a well-planned development of high-quality tourism that links the lake through the Arve valley with the Annecy area, which is highly developed in terms of tourism. Numerous mountain walking tours can be included in this programme.

The area around site PH in Cercier and Marlioz is not currently developed touristically and does not have noteworthy infrastructures.

The zone close to the Vuache next to site PD in Dingy-en-Vuache and Vulbens, on the contrary features,
numerous bicycle paths (including ViaRhôna) that are inviting for tourists interested in nature.

The site PL in Challex is embedded in a regional nature and bicycle tourism area, linking the Jura mountains with the Rhône valley. It features hiking paths and trails through the vineyards. The area around the Swiss commune Dardagny is known as one of the most beautiful in Switzerland and is therefore particularly protected along with the landscape that surrounds it.

*Economic development projects* Development projects potentially relevant for the FCC scenario are included in the Geneva cantonal master plan (Plan Directeur Cantonal, PDCn) and concern the period to 2030. A project for new apartments on about 180 ha in the vicinity of the airport, involving major construction works and the employment of about 5700 workers, is potentially relevant for site PA in France. Also, about 1300 apartments are planned to be constructed in nearby Grand-Saconnex, involving up to 2400 workers. No development projects are registered in the vicinity of sites PL in Challex and PB in Presinge on the Swiss side.

In France, the potential main developments are in the vicinity of site PA in Ferney-Voltaire. A future commercial activity zone (ZAC) on about 65 ha and the creation of an additional 2500 apartments and educational facilities are planned for the period up to 2030.

In the vicinity of site PD in Nanpy a new road widening project (RD903) and the intersection with the A40 autoroute are scheduled to be implemented before 2030.

*Scientific activities* The main scientific project in the region is the upgrade of the Large Hadron Collider, known as the High-Luminosity Large Hadron Collider (HL-LHC). It guarantees the continuation of the presence of scientists and engineers at today's level until the 2040 s. The FCC implementation scenario builds on this activity, leveraging the existing LHC Pt8 for the creation of surface site PA and hosting the injector on the CERN Prévessin site. Also site PL in Challex profits from being in the vicinity of CERN Meyrin.
<figure><img src="image_180.png" /><figcaption>**Fig. 3.47** Architectural heritage photographed during the field investigations</figcaption></figure>

For site at PB, the presence of the Geneva Architecture and Landscape School (HEPIA) in Lullier may be relevant. This facility is close to the site and potentially provides services that the surface site can leverage to reduce its own requirements. HEPIA could also potentially profit from common developments in different areas around the FCC, including agricultural studies and technical infrastructures. A collaboration already exists between the study, CERN and HEPIA to work on the re-use of excavated materials and agricultural aspects.

The national milk and meat industry school can be found in the vicinity of the PF site in Éteaux in La Roche-sur-Foron. The infrastructure also hosts a technical and scientific high-school. The school is active in scientific partnerships with INRAE, CNRS, universities and national research centres. Potential synergies can, for example, be found in the development of water and heat re-use.

### 3.3.10 Heritage

The analyses carried out in the frame of this study related to cultural, architectural and archaeological heritage first took into account all noteworthy elements that could be identified in a perimeter of 500 m around the surface sites. An example of architectural heritage is shown in Fig. 3.47. A subsequent, more detailed assessment focused on the elements in the immediate vicinity of the surface site candidate locations. This choice of perimeter was established in order to understand the richness of each surface site which, subsequently, would need to be considered in the designs and territorial integration of the sites.

Bibliographic analyses did not reveal any registered archaeological sites or interest in archaeological relevance at and in close proximity to the surface sites. There are no buildings or monuments of historical importance on the surface sites or directly affected by potential surface site constructions due to visibility or co-visibility. There are a few buildings of historical significance in the wider perimeters of some of the surface sites.

The sensitivity of the area of PA in Ferney-Voltaire, France with respect to heritage is low, particularly at the surface site itself. The site would be located on protected agricultural land. To the west of the study area, there is the protected woodland, Bois de la Mouille, also classified as wetland. To the northeast, in the vicinity of the site, there are a few isolated protected trees and a wetland with low functionality. Nevertheless, the implementation of a surface site avoids these classified and protected areas, despite the fact that some of them are on agricultural land.

The area around the site PB in Presinge, Switzerland has a strong heritage, architectural, cultural and landscape character. The surface site is relatively far from heritage sites but it remains partially visible from the hamlets to the north as well as those to the south. The existing wooded strips partially protect the views towards the villages of Choulex, Puplinge and Presinge, but remain open towards the communes of Jussy and Meinier. In order to preserve the rural character of the area, it is advisable to consider good landscape integration, such as a semi-buried surface site so that visibility from nearby hamlets is limited.

The heritage sensitivity within the study area of the PD site in Nangy, France, is considered medium to very high depending on the part of the site. The presence of the Château de Pierres and a classified wood located to the north and west, 180 to 300 m from the surface site induced this rating. In the area directly concerned by the site, the sensitivity is very low. The site is in the immediate vicinity of an autoroute and a departmental road which will be reorganised to improve traffic flow. No relevant visibility issues are recorded in an area that is dominated by high traffic, a hospital, or industrial and commercial facilities.

Sensitivity to heritage in the area of the PF surface site in Éteaux in France is low. Very high issues are noted in the wider vicinity of the site to the south and the southeast due to a woodland around a creek that is classified and protected. To the north-west, at a distance of about 400 m, there is a notable building, constructed in 1923, which formerly housed a cheese factory. There are also several groups of isolated trees that are witnesses to the history of agriculture. However, the implementation of the surface site avoids all sensitive spaces and stays close to the departmental road, directly opposite a public works construction company.
<figure><img src="image_181.png" /><figcaption>**Fig. 3.48** Mountainous landscape with agricultural fields documented during field investigations, highlighting the interaction between natural and cultivated environments</figcaption></figure>

The sensitivity related to heritage at site PG in Groisy and Charvonnex in France is considered to be low. Some areas in the south of the main site are remarkable due to the presence of areas with wetland characteristics and unclassified but high-quality woodlands. There are a few old buildings linked to the networks of old mills located in the surrounding larger study area. The surface site does not directly affect any heritage elements.

Heritage sensitivity in the immediate area of the PF surface site in Cercier and Marlioz, France is considered very low. This assessment is linked to the presence of the large forest (Grand Bois) and the Tabassé creek to the north of the surface site. Both present ecological interests, but are not considered heritage sites.

The heritage sensitivity of the PJ surface site in Dingy-en-Vuache and Vulbens in France is considered medium to high due to the location of the site in an area classified as a protected agricultural area and an ecological corridor protection zone. The entire zone is of agricultural character. In the south-west, in the immediate vicinity, some areas exhibit very high sensitivity due to the presence of classified woodlands along small creeks. The current shape of the surface site respects the integrity of the constraints. Still, particular attention will have to be paid for the specific design and integration of the surface site to maintain the registered ecological corridor, ensuring the free movement of fauna in the area.

The heritage sensitivity for the PL surface site in Challex, France is considered to be medium to high. The area around the site consists largely of protected agricultural and, further away, natural lands. There are several groups of isolated trees and alignments that bear witness to the history of agriculture. The site itself is located in a protected agricultural area and borders a protected ecological corridor registered in the municipal urban plan. The main issue is the visibility of the site from several locations in nearby villages. Therefore, care has to be taken for the specific design and landscape integration of the surface site.

In summary, the main heritage constraints are mostly related to the rural and agricultural character of the areas, with the presence of historical buildings at some distance from the sites. Particular attention related to heritage has to be paid during site design and landscape integration at the site locations PB, PJ and PL.

### 3.3.11 Landscape

The initial state analysis included a detailed landscape analysis that was carried out with expert companies during field visits over an entire year. An example of the landscape considered is shown in Fig. 3.48. The landscape analysis extended up to 5 km around the surface sites, since the visibility of the sites depends significantly on the topography, urban and vegetation environment. Detailed landscape analysis and maps were developed that show the topography, the views from and to the sites and the visibility issues. They will serve as input for subsequent architectural design works and landscape integration concepts.

The site PA and its surroundings in Ferney-Voltaire (France) are dominated by agricultural areas, Geneva airport, highly urbanised commercial surroundings and an ecological corridor between the residual forests that occupy the buffer along the Franco-Swiss border. The area is in an open landscape with a view towards the Alps and Mont Blanc that has to be considered during the architectural design of the surface site. The nearby LHC site Pt8 (LHCb) and its planned extension provide an excellent opportunity to reduce the PA site footprint as much as possible to preserve the view and the ecological corridor that also stretches across the border.

The site PB in Presinge (Switzerland) is located in open countryside with valuable views towards the Alps and the Salève mountain. The landscape continuity is remarkable and the views from nearby hills over the landscape and its cultural and landscape heritage are highly valued. Much care must be taken in the architectural designs of the site, ideally integrating the site in the landscape as much as possible, taking care that the view from the nearby villages towards the mountains remains unobstructed.

The PD site in Nangy (France) is located in a mixed urban, agricultural and industrial environment that is dominated by major transport routes. Direct views to the sites are limited.
<table><caption>**Table 3.14** Typical noise levels with practical examples</caption><thead><tr><th>Noise</th><th>dB(A)</th><th>Level</th><th>Conversation</th></tr></thead><tbody><tr><td>Jet plane takeoff</td><td>&lt; 130</td><td>Above pain threshold</td><td rowspan="2">Impossible</td></tr><tr><td>Jackhammer at 1 m</td><td>&lt; 110</td><td>Supportable for a short moment</td></tr><tr><td>Motorcycle at 2 m</td><td>&lt; 90</td><td>Annoying</td><td>Possible when shouting</td></tr><tr><td>Heavy road traffic</td><td>&lt; 80</td><td>Very noisy</td><td>Difficult without shouting</td></tr><tr><td>Dwelling close to an autoroute</td><td>&lt; 70</td><td>Noisy</td><td>Possible when speaking loud</td></tr><tr><td>Working on a computer</td><td>&lt; 60</td><td>Moderate</td><td rowspan="2">Possible with normal voice</td></tr><tr><td>Noise level in a city during the day</td><td>&lt; 50</td><td>Rather quiet</td></tr><tr><td>Construction noise at 100 to 200 m distance from a surface site</td><td>40 - 45</td><td>-</td><td rowspan="3">Possible with quiet voice</td></tr><tr><td>Noise level in the countryside during the day</td><td>&lt; 40</td><td>Quiet</td></tr><tr><td>Noise level in the countryside during the night without wind</td><td>&lt; 30</td><td>Very quiet</td></tr><tr><td>Snow falling in the mountains, recording studio</td><td>&lt; 15</td><td>Silent</td><td></td></tr></tbody></table>

The PF site in Éteaux (France) is located in a natural environment, directly on highly frequented transport routes and commercial premises. No direct visibility from La-Roche-sur-Foron exists. However, the mountain views towards the Alps need to be considered when developing the architectural design of the site.

The site PG in Charvonnex and Groisy (France) is located in a highly natural environment, partially forested and with grass fields. The mountain views from the site are highly valued. A direct, but limited view of the site only exists from the Olières plateau.

The PH site in Cercier and Marlioz (France) is located in a rural environment with a forest. Some hamlets exist in the vicinity, but due to the forest and the topography, no direct view of the site exists.

The PJ site in Dingy-en-Vuache and in Vulbens (France) is located in a mixed natural and agricultural environment. The landscape is open and the view from Vulbens must be taken into consideration during the architectural design.

The site PL in Challex (France) is located in an agricultural/vineyard environment with views to the Jura mountain, the Rhône valley and the Alps. The open views require careful landscape integration, considering in particular the site's visibility from the nearby hamlets.

### 3.3.12 Noise

Noise, is considered to be unpleasant or annoying and is an environmental aspect that is relevant during the construction of the surface and subsurface structures and during the operation of the particle collider. The regulations concerning noise protection differ significantly between France and Switzerland. However, in all cases the impact due to noise depends on the presence of people and animals that would be affected by the noise. The relevant indicators are not only frequency and amplitude, but also the time during which an exposure to noise occurs and the duration of the exposure: during ordinary working hours, during the night, on non-working days, the typical presence of people in their homes, the age, health and other social conditions of the potentially affected people (e.g., noise in the vicinity of a hospital, a school or a retirement home). Typically, noise generated by machinery is considered to have noteworthy health effects from 40 dB(A) and higher. Noise up to 30 dB(A) is a level that is generally experienced by persons in a typical living environment (see Table 3.14).

Therefore, the first step required is to establish the existing background noise in the vicinity of the candidate surface sites using devices like those shown in Fig. 3.49 and Fig. 3.50. This activity is followed by estimations of noise generation without protection measures. This identifies sensitive areas. An eco-design is subsequently applied to reduce the noise where potential impacts on the environment are expected. The approach is to first work on low-noise designs. This also includes the relocation of noise-generating devices on the surface sites. Where this process turns out to be insufficient, noise protection measures to reduce the impacts are studied. Relocation of noise-generating equipment or adjustment of an entire surface site is an option that is considered if no adequate mitigation measures can be identified.

The background noise was established by first consulting national noise emission databases and then completing the data with field measurements. The measurements were carried out by expert companies on various days in 2024 at a selection of different locations and at different distances from the surface sites. Detailed analysis of the
**Fig. 3.49** Field-based noise measurements conducted to assess ambient sound levels

<figure><img src="image_182.png" /></figure>

**Fig. 3.50** Noise measurements taken near a residential area to understand the current noise level

<figure><img src="image_183.png" /><figcaption>**Table 3.15** Typical background noise measured in the vicinity of surface sites and the numbers of people potentially affected within the distances indicated from the site</figcaption></figure>

<table><thead><tr><th>Site</th><th>Background noise dB(A)<br>7 h-22 h</th><th>Background noise dB(A)<br>22 h-7 h</th><th>Potentially<br>affected people</th><th>Distance to<br>site</th></tr></thead><tbody><tr><td>PA</td><td>55</td><td>45</td><td>0</td><td>100 - 200 m</td></tr><tr><td>PB</td><td>36</td><td>36</td><td>0<sup>†</sup> (&lt; 10<sup>‡</sup>)</td><td>100 m</td></tr><tr><td>PD</td><td>48</td><td>44</td><td>0</td><td>100 - 200 m</td></tr><tr><td>PF</td><td>48</td><td>40</td><td>~10</td><td>100 - 200 m</td></tr><tr><td>PG</td><td>36 - 48</td><td>37 - 45</td><td>0</td><td>100 - 300 m</td></tr><tr><td>PH</td><td>35</td><td>29</td><td>&lt; 10</td><td>100 m</td></tr><tr><td>PJ</td><td>39 - 47</td><td>35 - 44</td><td>0</td><td>300 m</td></tr><tr><td>PL</td><td>40</td><td>30</td><td>&lt; 5</td><td>200 m</td></tr></tbody></table>

† People exposed according to Swiss limits, DS III

‡ People exposed according to permitted noise emissions in France

frequencies, amplitudes, and directions of origins have been made to permit mixing potential noise sources at the surface sites with the ambient noise at a later stage. The number of potential residents that could be affected by noise has been obtained using an analysis of the data collected with the geographical information system and statistical information (see Table 3.15).

The measurements indicate that the majority of sites are affected by significant background noise with no people present in a perimeter of 200 to 300 m. Therefore, neither the noise from construction nor operation, that will be kept as low as possible with noise protection measures, is expected to impact the population at sites PA (Ferney-Voltaire), PD (Nangy), PF (Éteaux), PG (Charvonnex and Groisy), PJ (Dingy-en-Vuache and Vulbens). At the PL
site (Challex), construction activities during the night could lead to an excess of background noise, and therefore, the construction schedule would have to be adapted if a detailed technical design of the construction site in view of noise protection turns out to be insufficient. At sites PB (Presinge) and PH (Cercier and Marlioz) the background noise is particularly low with about 35 dB(A) compared to all other locations. In all cases, operation related noise can be kept below the threshold for residents potentially affected in the vicinity, but for the construction planning, care must be taken to respect the times during which noise exposure is more impactful (e.g., during the night, weekends and non-working days). For site PH, 3 to 4 houses at a distance of 100 m would be affected, and at site PB, two houses at a distance of 200 m would be affected. The construction-induced noise should, therefore, not significantly exceed the background noise during resting times in these locations.

### 3.3.13 Vibrations

Vibrations are rapid oscillating movements that propagate through solid paths and can be transmitted to the human body, especially through direct contact with the ground or the structure concerned. They are thus physical phenomena characterised by a wave with its amplitude and frequency.

The risks associated with vibrations are mainly damage to buildings and disturbance of people. Vibrations can occur due to seismic activities, ground movements, meteorological conditions and artificial sources such as construction activities and machinery. The environmental analysis revealed that in the entire perimeter of the project, seismic activities have a very weak to weak potential to create relevant vibrations, despite different occurrence probabilities for small-scale seismic events. Concerning vibrations caused by landslides surface site locations PA, PB, PD, PH, PJ and PL are at significant distances from risk zones and no subsurface cavities exist within a relevant distance of surface sites. A potential landslide risk zone exists only at a distance of 500 m from the PF site, but the likelihood of an event is very small. A cavity that is part of a defence infrastructure exists at a distance of 250 m. It is unlikely that this cavity would collapse. Weather phenomena such as violent winds and lightning may cause vibrations that affect trees and building structures. However, such events are infrequent in the perimeter of the scenario. Various human-induced vibration sources over the coming ten years were identified in the vicinity of surface sites PA, PD and PF. Road traffic is another source of ongoing vibration. It needs to be considered for sites PA, PD, PF, PG and PJ. No other noteworthy sources of vibrations could be identified in the vicinity of surface sites.

### 3.3.14 Light

Light pollution refers to the excess or poor management of artificial light in the nighttime environment. This phenomenon is increasingly concerning, both for its effects on biodiversity and human health. There are two types of light pollution. First, direct light pollution relates to the impact of light directly produced. Secondly, indirect light pollution results from an accumulation of light, creating a halo that obscures the stars and degrades the quality of the night sky. With respect to the surface sites, light pollution is a relevant environmental topic to be assessed during the detailed design phase concerning the construction activities and the subsequent operation phase. Therefore, at this stage, the existing light pollution in the vicinity of the candidate locations for surface sites has been analysed and documented to serve as a baseline for the development of the detailed design.

The main source of light pollution in the areas concerned by the project is public lightning along roads in residential areas. In addition, commercial zones are a source of artificial light, in particular when they use large-scale public screens. Frequently, lights are not controlled. Some outdoor lights of private houses contribute to light pollution. Finally, industrial installations for operation during nighttime and to ensure safety are a strong source of light pollution.

For the current state, data have been purchased from various sources, and maps have been developed using these data for the areas around the surface sites. The zone around site PA is strongly illuminated during the night. One source is the Geneva airport and another one is the commercial zone in the immediate vicinity. Road lighting and newly built residential houses also contribute. The Grand Genève plan foresees that the entire area is gradually restored to protect the ecological corridors and the fauna. However, no protection measures are currently planned at local French urban planning level. Site PB in Switzerland is located in the countryside and only few buildings are found in the vicinity. In the Grand Genève plan, the perimeter is classified in order to protect the ‘night’. In particular, the zone close to the road is subject to refurbishment and the zone along the creek has a stake. However, no protection measures are mentioned at local urban levels. Site PD is in the immediate vicinity of major transport routes and industrial buildings on a field. No particular protection measures are planned at local urban planning level. Site PG is in a natural environment and in the forest with only little light pollution. Although no particular protection measures for the location exist, it can be assumed that preserving the current situation is a priority. Also, site PH in the forest is in an area with very low light pollution.

Although no particular protection levels are indicated it can be assumed that the current situation is to be preserved as much as possible. Site PJ in the countryside experiences small light sources in the vicinity from
<figure><img src="image_184.png" /><figcaption>Fig. 3.51 Types of radiation (Source: IAEA [90])</figcaption></figure>

some distant urban constructions. The zone is classified to be preserved, and the ecological corridors constitute a stake. General protection measures apply to forbid artificial light along the water courses although at local urban planning level, no protection zones are indicated. Site PL is located in an agricultural zone and rather isolated next to fields, forests and vineyards. In Switzerland, nature protection zones forbid artificial light. At the local urban level, no protections apply in France.

Summing up, the site PD and its surroundings are located in an area where the night should be preserved with priority. However, no noteworthy species are affected and therefore the stake is average. The PA site is, however, in an area with high light pollution and there are ecological stakes in the surrounding area. Therefore, there is a will to restore the night environment, and the stake is high. The stake is also high for the PB site in Switzerland, since the night is intended to be preserved and light pollution should even be further reduced. Also, the stake for site PF is high since the site is located in an area with almost no light pollution today. Similar conditions with high stakes apply to sites PJ and PL. The wider surroundings of sites PG and PH are in a forest with low light pollution and nearby noteworthy biodiversity reservoirs. Therefore, the stakes with respect to light pollution are very high. These findings have to be considered and integrated in the design and planning of the construction sites and a plan to preserve the night has to be developed for all sites concerning the operation phase.

### 3.3.15 Radiation

Possible risks for the population and environment emerging from non-ionising and ionising radiation exposure at different locations on the surface were analysed based on available data in both Host States. Figure 3.51 shows the different types of radiation, non-ionising and ionising, that exist.

The Host States notified services in charge of carrying out measurements to establish national databases will require updated data before a particle accelerator is put into operation to establish a baseline for the ionising radiation.

*Non-ionising radiation* In France, exposure limits vary depending on the frequency range used, typically between 28 V/m and 87 V/m for the electric field. The Swiss regulations distinguish between public areas in which the persons stay only for brief intervals of time, such as roads or sports facilities, and sensitive areas, in which the persons may stay for a certain limited period of time including houses and apartments, schools, and hospitals. Switzerland imposes stricter installation limits for radio equipment than France, with maximum electric field values set at 4 V/m for 900 MHz, 6 V/m for 1800 MHz, and 5 V/m for installations operating across multiple frequencies. These Swiss regulations are designed to provide enhanced protection for sensitive locations compared to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines. Swiss limits with respect to immission, which represent the cumulative exposure from all emitters, align with European recommendations and are identical to those in France. Figure 3.52 shows the values of the electric and magnetic fields measured under the line, as well as at 30 m and 100 m from the line, for very high voltage, high voltage and low voltage overhead lines.

No electricity lines are emitting low-frequency radiation in the vicinity of sites PB in Switzerland, PD, PG, PH, PJ and PL in France. A 63 kV line runs 250 m in the vicinity of the PF site in Éteaux in France, which emits a negligible electromagnetic field onto the candidate surface site. The 66 kV underground electricity line supplying LHC Point 8 in Ferney-Voltaire in France is just next to the PA site. It induces a very weak electromagnetic field onto the site.

Some radio stations that are sources of radio waves are present near the surface locations, but the recorded exposure measurements are well below the reference levels. The data collected from measurement stations near PA, PB, PD, PG, PJ show that all exposure measurements are significantly below the reference levels. No data was found for measurements within a 5 km radius of the PF, PH and PL locations in France. Detailed measurements will have to be carried out before the installation is put into operation, but the risk of exceeding the limits for ionising and non-ionising radiation specified in the regulations is considered to be very low.
<figure><img src="image_185.png" /><figcaption>**Table 3.16** Level of exposure to ionising radiation at the surface site locations today</figcaption></figure>

<table><thead><tr><td>Nearest data entry</td><td>Annual exposure</td><td>Surface site</td></tr></thead><tbody><tr><td>Ferney-Voltaire</td><td>5.2 mSv/year</td><td>PA (Ferney-Voltaire, France)</td></tr><tr><td>Ville-la-Grand</td><td>4.0 mSv/year</td><td>PB (Presinge, Switzerland)</td></tr><tr><td>Nangy</td><td>4.3 mSv/year</td><td>PD (Nangy, France)</td></tr><tr><td>Éteaux</td><td>4.4 mSv/year</td><td>PF (Éteaux, France)</td></tr><tr><td>Groisy</td><td>4.4 mSv/year</td><td>PG (Charvonnex and Groisy, France)</td></tr><tr><td>Charvonnex</td><td>4.9 mSv/year</td><td>PG (Charvonnex and Groisy, France)</td></tr><tr><td>Marlioz</td><td>4.9 mSv/year</td><td>PH (Cercier and Marlioz, France)</td></tr><tr><td>Cercier</td><td>5.0 mSv/year</td><td>PH (Cercier and Marlioz, France)</td></tr><tr><td>Dingy-en-Vuache</td><td>5.0 mSv/year</td><td>PJ (Dingy-en-Vuache and Vulbens, France)</td></tr><tr><td>Vulbens</td><td>5.8 mSv/year</td><td>PJ (Dingy-en-Vuache and Vulbens, France)</td></tr><tr><td>Challex</td><td>5.5 mSv/year</td><td>PL (Challex, France)</td></tr></tbody></table>

Source: Autorité de sûreté nucléaire et de radioprotection (ASNR)

**Ionising radiation** Ionising radiation carries sufficient energy to ionise atoms or molecules, leading to molecular changes. High doses can cause cellular damage and mortality, whereas controlled applications are pivotal in industries, scientific research, and medicine. The sources of exposure are of natural and artificial origins:

* Natural cosmic radiation: energetic particles from space contribute to exposure, influenced by altitude and geographic location. Terrestrial radiation: radioactive elements in the Earth's crust (e.g., uranium, thorium) emit radiation, varying regionally due to geological factors.

* Natural radon gas: a significant contributor, radon accumulates in poorly ventilated indoor spaces. It constitutes 33% of annual exposure in France. Incorporated radionuclides: naturally occurring radionuclides in food and water contribute 12% to annual exposure.

* Artificial sources, nuclear accidents and testing: fallout from historical nuclear tests and accidents like Chernobyl contributes marginally to current exposure.

* Nuclear facilities: emissions from civilian and military installations are tightly regulated, with negligible contributions (0.001–0.01 mSv/year near facilities).

* Artificial sources, medical applications: diagnostic and therapeutic uses dominate artificial exposure, contributing 34% of total exposure in France.

* Artificial sources, scientific research activities: the particle accelerators and colliders operated by CERN contributing less than 0.01 mSv/year.

Table 3.16 gives an overview of the current ionising-radiation background conditions at the surface site locations. Exposure to cosmic radiation, originating from high-energy particles such as protons and heavy ions from space, poses hazards due to its ionising nature, which can damage living tissues. The intensity of exposure increases with altitude, being roughly twice as high at 1500 metres compared to sea level and further elevated during air travel. While the Earth's magnetic field reduces exposure near the equator, higher doses are received near the poles. In France, cosmic radiation accounts for about 7% of the average annual exposure to ionising radiation, with an effective dose at the surface sites between 0.32 and 0.70 mSv/year. In Switzerland, the dose associated to cosmic rays in the vicinity of the site is about 0.35 mSv/year.
Telluric radiation refers to ionising radiation emitted by naturally radioactive elements like uranium, thorium, and potassium-40 found in the Earth's crust. Exposure levels vary depending on regional geology, with areas rich in granitic or volcanic rock typically exhibiting higher radiation levels. In France, telluric radiation contributes approximately 14% of the average annual exposure to ionising radiation, with an effective dose of around 0.51 to 0.55 mSv/year in the areas of the surface sites in France and 0.33 mSv/year in the vicinity of the surface site in Switzerland.

Exposure to natural radionuclides occurs through the ingestion of radioactive elements, such as polonium-210, present in food, water, and air, which originate from terrestrial rocks, soils, or cosmic interactions. Foods like seafood are particularly rich in these radionuclides, and tobacco inhalation can also contribute significantly. In France, this accounts for approximately 12% of the average annual exposure to ionising radiation, with an effective dose of about 0.55 mSv/year in France, varying between 0.4 and 3.1 mSv/year depending on dietary habits. In Switzerland, the exposure is about 0.40 mSv/year. Tobacco consumption accounts for about 0.04 mSv/year.

Exposure to radon, a naturally radioactive gas, varies between France and Switzerland due to differences in geology and measurement methodologies. In France, radon contributes 33% of the average annual ionising radiation exposure, with a mean dose of 1.5 mSv/year, ranging between 0.54 and 3.2 mSv/year. Specific areas concerned by the surface sites in Ain and Haute-Savoie report slightly lower exposures, around 1.47 and 1.14 mSv/year, respectively. In Switzerland, radon is the largest natural contributor to radiation, with an average dose of 3.3 mSv/year, reflecting a higher impact. This discrepancy partly arises from different dose conversion factors used; France employs the UNSCEAR coefficient, while Switzerland uses the CIPR's updated factors, which approximately double the estimated risks. Consequently, radon exposure is relatively more significant in Switzerland.

Exposure to ionising radiation from artificial sources in France and Switzerland includes contributions from nuclear accidents, medical applications, nuclear installations and scientific research facilities.

Medical applications in both France and Switzerland, are the largest contributors to artificial ionising radiation exposure. In France, they account for approximately 1.5 mSv/year per capita, representing 34% of the total radiation exposure. Similarly, in Switzerland, medical applications contribute about 1.49 mSv/year per capita, highlighting the widespread use of diagnostic and therapeutic procedures involving ionising radiation in both countries.

Radiation exposure due to past nuclear accidents and fallout, such as Chernobyl, and atmospheric nuclear tests are now minimal in both countries. In France, the average annual dose is 0.012 mSv/year, with slightly higher doses in areas with significant fallout. In Switzerland, this exposure is even lower, contributing only a few hundredths of a mSv annually, reflecting the diminished impact of residual fallout over time.

Exposure from nuclear facilities is negligible in both France and Switzerland due to strict regulatory measures. In France, people living within 10 km of nuclear installations receive an annual dose of 0.001 to 0.01 mSv under normal operational conditions. In Switzerland, exposure near nuclear facilities and the scientific facilities of CERN, is similarly low, with annual doses generally below 0.004 mSv, demonstrating effective safety and monitoring measures.

Summing up, the ionising radiation context at the surface sites is significantly larger than the residual ionising radiation that is generated by CERN's scientific particle accelerators.

### 3.3.16 Technical risks

**Natural Hazards** As part of this study, several types of natural hazards that can potentially lead to interactions with the project have been identified. These will be analysed in further detail during a subsequent environmental impact assessment. The topics concern flooding, ground movement, seismic activities, avalanches, forest fires, cavities, radon, clay swelling and technological hazards. These natural hazards may also be caused by climate change effects. The evolution of the climate has been taken into consideration in the study of the current state of the environment, as well as the evolution of the environment in which the project would be embedded.

**Flood and ground movement** hazards that can be caused by numerous factors, such as rain, groundwater and rivers, are considered to have low probability for all the locations. Effects due to unstable ground, such as landslides, mudflows and erosion have also been taken into account. Overall, no significant hazards or potential effects leading to relevant risks were identified in the concerned locations. No surface site on French territory is subject to a ground movement. For the site PB in Presinge in Switzerland, the closest potentially unstable ground area is located 700 m east of the site, however the landslide risk is superficial. The candidate surface site location is not subject to the hazards linked to flooding or earth movement.

**Seismic** hazards vary depending on the location. France is divided into five seismic activity zones. The sites studied are located in zones of moderate or medium seismic activity. In particular, sites PA, PL and PJ are located in zones of moderate (level 3) activity, while sites PG, PF and PD are located in zones of medium (level 4) activity. This
requires the application of earthquake-resistant construction principles during the surface site design development. In addition, some of the sites studied are located near active tectonic faults. For example, site PA in Ferney-Voltiare is located about 400 m from a fault. In Switzerland, the seismic hazard model classifies locations into five zones, of which site PB in Presinge is located in zone Z1b (level 2), characterised by low seismic activity. Further field studies are needed, and cooperation with scientific institutions to assess the local seismic risk in detail and develop specific engineering models will be undertaken.

**Forest fires** turn out to be a very low hazard in the zones concerned by the surface sites, although two locations are in forest zones. In France, the Forest Fire Risk Prevention Plan (PPRIF) established at the municipal or inter-municipal level, targets areas exposed to significant risk levels and strong land pressure. In addition, the PPRIF may also impose clearing of areas in order to isolate the buildings. It may also require that access roads be sized to allow fire trucks to pass and for people to evacuate in the event of a fire. No French municipality affected by the surface sites is subject to a forest fire risk prevention plan and none of the areas surrounding the surface sites in France are subject to the legal obligation of clearing. Although the site location PH in Cercier and Marlioz is not exposed to the natural forest fire hazard according to various regulatory and management tools, there always remains a residual and low hazard of forest fires in this area due to the presence of timber. In Switzerland and more specifically in the canton of Geneva, there is no law, prevention plan or specific forest fire risk management plan. The site PB in Presinge is not in the vicinity of a woodland that would generate a forest fire hazard to the site.

**Avalanches** are not considered a relevant hazard for the surface sites due to relatively flat terrain and low forest density in the vicinity of the locations analysed.

**Cavities** natural or man-made voids can be considered hazards for construction activities. The analysis addressed their presence and potential effects with respect to the implementation of the surface sites. No cavities are located within a radius of 500 m around the French surface sites, except for the PG Charvonnex site where several cavities linked to military works are located within a radius of more than 250 m around this site. Apart from their existence and location, no additional information is available. Thus, the potential hazard from underground cavities in this area requires additional data gathering.

**Radon** is a colourless, odourless radioactive gas that originates from the decay chains of uranium and thorium, both naturally present in the Earth's rocks. A key factor influencing radon concentration levels in buildings is the geology, in particular, the uranium content in the subsurface layers. In some areas, specific underground features (e.g., faults, mining works, hydrothermal sources) can exacerbate radon transfer to the surface, locally increasing its potential. For new constructions, radon transfer can be limited by enhancing the building's seal between the ground and the structure. In France, the mapping method estimates the radon potential of geological formations by considering factors that influence both radon production in the subsurface and its transport to the surface. Zones are classified as having low, moderate, or high potential. All French surface sites studied are located in low radon potential zones.

In Switzerland, the radon map shows the probability in % of exceeding 300 Bq m⁻¹ in buildings, divided into four categories: ≤1%, 2 and 10%, 11 and 20%, and >20%. Unlike France, there is no national campaign that estimates radon thresholds in buildings. The PB site in Presinge lies in a low-risk area, in the range of 2 to 10% probability of exceeding 300 Bq m⁻¹.

**Shrinking and swelling of clays** is a natural hazard that has been assessed for all surface site locations. Superficial clay soils have the ability to change consistency depending on their water content. When the water content of clay soil increases, its volume expands, a phenomenon referred to as the swelling of clays. Conversely, a reduction in water content causes the opposite effect, known as shrinkage of clays. Figure 3.53 explains the mechanism of the shrink-swell phenomenon. This shrinkage or swelling can cause structural damage to buildings.

From January 1, 2024, in France enforcement of the construction regulations has been tightened, and a new certificate for clay shrink-swell behaviour is now mandatory in zones subject to medium or high exposure. The surface sites located in France are subject to low to medium exposure to shrink-swell risks. Site PA in Ferney-Voltiare is mostly in a low hazard area, except for a small part of the site near the LHC site point 8 (LHCb) where the exposure level is medium. Sites PD, PF, PG and PF are rates as low exposure. PH and PJ sites are located in zone with medium exposure. The PL surface site in Challex is mainly located in the zone with low exposure, except for a small fragment in the southern part of the site with medium exposure, which is not foreseen to host constructions, but a green buffer. In Switzerland, a lithological map that provides an overview of the subsoil classified according to lithological and petrographic criteria indicates that the site PB in Presinge is located in soils containing clays. However, the concentration and depth of this clay element in the soil are not precisely described. Detailed soil investigations are required during a subsequent environmental impact and surface site design phase to clarify the conditions and, if needed, to take them into account during the design of the surface site.
**Fig. 3.53** Expansion and shrinkage of clays. Damage to the building is caused by the rain induced expansion on one side and shrinkage caused by removal of water by the tree on the other

<figure><img src="image_186.png" /></figure>

*Technological hazards* Technological hazards linked to industrial, environmental, and infrastructural activities could potentially have effects on human health, safety and the surrounding environment. Risks emerging from these hazards and effects arise from industrial installations, the transport of hazardous materials and other activities involving dangerous substances. Therefore, their presence near candidate surface site locations has been analysed.

In France, two categories of industrial facilities are considered to generate risk. The first group concerns establishments reporting emissions and transfers of pollutants into the air, water or soil and the production of hazardous waste. This covers establishments such as large industrial installations, large municipal sewage treatment plants and certain livestock farms. Second, installations classified for environmental protection (called ICPE) that are industrial or agricultural facilities subject to regulations for the prevention of environmental risks and are classified according to regimes ranging from simple declarations to authorisations, depending on the risk. In addition, the SEVESO regulations (EU Directive 2012/18/EU) impose strict controls on facilities processing hazardous chemicals in order to prevent serious accidents.

In Switzerland, the Ordinance on Major Accident Prevention (so called OPAM) seeks to protect people and the environment from severe damage caused by extraordinary events in installations or during the transport of hazardous materials. OPAM applies to businesses exceeding specific hazardous material thresholds, genetic organisms under strict confinement, and transport infrastructures like pipelines, railways, and highways used for dangerous goods. The planning authorities (cantons and municipalities) are responsible for integrating aspects of major accident prevention into their plan for land use. Although Switzerland does not apply the SEVESO directive, OPAM adopts even stricter thresholds for hazardous substances and includes transport routes, pipelines, and dangerous microorganisms within its scope.

A gas pipeline passes through the PA annex surface site near the LHCb, extending from Switzerland and running along the edge of the main PA surface site towards the north. This installation must be taken into account when designing the surface infrastructure; however, there are no hazardous industrial installations located near the PA site, and the main threats might come from the proximity of major communication arteries (airport and departmental routes) that can transport dangerous goods.

There is a gas pipeline approximately 200 m south-west of the PB surface site which poses a potential risk of an accident involving hazardous materials. The Route de Jussy, classified as a major transit route, runs alongside the eastern boundary of the site. This road is subject to regulations concerning the transport of dangerous goods under the Swiss OPAM ordinance. Apart from these, there are no other industrial installations, facilities declaring pollutant emissions, or safety perimeters within the vicinity of Site PB.

The PD, PF and PG surface sites are located near major transport routes (highways and departmental roads) that are used for regional and national goods transport, including hazardous materials, creating potential risks of accidents or spillages. A railway line currently used for passenger transport passes near the PG site. Neither the PD or PG sites have other classified industrial facilities or pollutant-emitting sources within a 500 m radius, ensuring a relatively low environmental risk. The classified installation for environmental protection SARL Luc
Maulet, which handles inert waste, is located 150 m from the PF surface site near the A410 but poses no risk as its activities are related to the storage of non-recoverable inert waste.

There are no major roads or highways within a 500 m radius of PH surface site, there are just local roads and paths, which significantly reduces transport-related risks involving hazardous materials. There are also no classified installations, pollutant-emitting facilities, or other industrial sites in proximity. However, there is a gas pipeline near the PH site and special attention should be paid to heavy transport that would cross the gas pipeline route.

Apart from the presence of the A40 autoroute located 50 m to the south of the PJ surface site and the associated potential exposure to risks associated with the transport of dangerous goods, there are no classified installations or establishments reporting releases and transfers of pollutants in the vicinity.

Also, for the PL surface site, apart from the proximity of the departmental road, no classified installations or establishments reporting releases and transfers of pollutants were identified within a radius of 500 m, including the Swiss territory.

The risk of the dam bursting has also been analysed. Such an event could cause water to leak from the reservoir and flood the surrounding areas to a greater or lesser extent. None of the communes in France where the surface sites are located are at risk of dam failure. In the canton of Geneva, there are two dams, each downstream of the PB surface site thus, the site is not subject to the risk of dam failure.

There is no nuclear installation present near the surface sites, in France and Switzerland. Furthermore, there is no facility subject to the ICPE nomenclature for activities related to pyrotechnic risk, within a radius of 500 m around the sites, on French territory. In Lake Geneva, the entire geographical area of the Petit Lac is polluted by the presence of munitions dumped between 1948 and 1979. These are munitions such as shells, rifle cartridges, aircraft bombs and other explosive residues. The PA and PB sites are located 4 km from the shores of the lake. Thus, these surface sites are not subject to the pyrotechnic risk associated with un-decommissioned munitions in the lake.

In summary, some sites are located near transport routes such as autoroutes, departmental roads and railways that carry or may carry dangerous goods. There is only a gas pipeline in close proximity to the PA, PB and PH sites, which needs to be considered when designing the surface site to minimise the risk of an environmental accident. However, there are no nearby nuclear facilities, polluting facilities or classified industrial facilities within 500 m of any surface site, and the risk of a dam failure or pyrotechnic hazards from munitions in Lake Geneva is minimal. Overall, these sites pose a relatively low environmental and safety risk, with special consideration being given to infrastructure near transport routes.

*Polluted sites* In France, polluted sites and soils are described as locations that, due to past waste disposal or pollution infiltration, pose ongoing risks to people or the environment. These issues often stem from outdated waste disposal practices, chemical leaks, or accidents. Some areas also experience pollution from atmospheric fallout, which has accumulated over many years. It is different from diffuse pollution, like that from agricultural practices or car emissions near major roads. Industrial or agricultural activities that could cause pollution or risks to the local population are considered classified installations and are subject to regulations. The national policy aims to prevent future pollution while managing existing sites and ensuring they are safe for their intended use. Three complementary databases (BASIAS, BASOL, SIS) provide comprehensive pollution diagnostics, with detailed inventories of polluted sites and their risk levels.

In Switzerland, polluted sites refer to locations where waste has been permanently stored, such as landfills, as well as areas where waste has been stored or infiltrated. Contaminated sites are those that cause harmful or disruptive effects on the environment or have the potential to do so in the future. Thanks to waste regulations established in the 1990s, Switzerland has prevented the creation of new contaminated sites, by prohibiting hazardous waste landfills and untreated urban waste. It has put the infrastructure for proper waste treatment in place, ensuring that any waste is handled responsibly.

For surface sites, PA, PD, PG, PH and PB there are sites listed in BASIAS, BASOL, SIS or Swiss database located within a radius of 500 m, however, none of the areas of PA, PB, PD, PF, PG, PH, PJ and PL have contaminated sites in immediate proximity.

### 3.3.17 Other projects

*Introduction* In an environment that is subject to continuous development, urbanisation and demographic development in a cross-border context, the constraints and opportunities that can emerge from other projects must be considered when conceiving a new research infrastructure with significant territorial development needs. Therefore, the analysis of the initial state of the environment included the establishment of an inventory of projects that were planned and constructed and that were potentially relevant to the FCC. Continuous monitoring needs to be implemented to keep this inventory up to date and to act rapidly in case a new project concept is developed, in order to understand if synergies are possible and to avoid potential conflicts emerging.

Today, the most relevant other projects to be considered are:
* Geothermal exploitation

* Lake crossing

* Grand Genève development project

* Grand Annecy development project

* Enlargement of the departmental road D903 and integration with the A40 autoroute in France

* District heat network in Switzerland

* Heat networks in France

* Water networks in Switzerland

* Water networks in France

* Railway network development Nord Genève

* Railway network developments in France

* Territorial development in the Dingy-en-Vuache, Vulbens, Valleiry sector

* Development of Groisy

* Development of Ferney-Voltaire and Geneva international sector

**Geothermal exploitation** The energy provisioning strategy of the canton of Geneva foresees extensive further development of heat recovery from geothermal sources that range from about 100 m depth to several hundred metres. The investigations carried out in the frame of the feasibility study reveal no incompatibilities between the FCC and existing geothermal installations today. Given the depth of the FCC subsurface structures, it cannot be excluded that further geothermal probes lead to potential conflicts. It is, therefore, of utmost importance to implement an early warning system based on the current reference trace that permits CERN, as the project owner, to engage with the persons who plan to create such installations. A minor displacement of the probe can frequently resolve any incompatibility. Should a probe be built without knowledge or until the subsurface volumes are properly protected from other projects, the conflicting geothermal probe would have to be removed, and the loss would need to be replaced. In France, no geothermal probes are known in the vicinity of the current reference scenario and no knowledge of a department or region-wide geothermal campaign exists. However, the need for reserving the subsurface volumes is equally important on French territory.

**Lake crossing** Various subsurface lake-crossing projects have been conceived on Swiss territory during recent decades in the sector of the FCC, but they are not in its immediate vicinity. Most recently, a metro railway tunnel project has been proposed. Such a project can lead to potential synergies as well as to potential conflicts. Synergies would exist around subsurface investigations, tunnelling technologies, and excavated materials management. Conflicts could arise from overlapping construction schedules that could lead to increased nuisances, increased difficulties for the management of excavated materials, availability issues for engineering companies and workers, and organisation of construction sites and activities. The convolution of the authorisation processes of two almost concurrent projects could eventually generate societal acceptance issues for both projects. Care must also be taken to ensure appropriate designs for both projects in case the two tunnelling projects overlap, although the depths differ.

**Grand Genève development project** Territorial planning documents in both host countries integrate the continuous development of a 'Grand Genève' in their planning documents. In addition, it is a cross-border project that involves substantial coordination. The project involves numerous improvements, such as road and railway mobility, urbanism, economic development, environmental sustainability, housing, social cohesion and cross-border governance. The project facilitates the extension of CERN's scientific activities in a larger zone. It also creates constraints, since the urban development implies stricter preservation of natural and agricultural zones. This rapid evolution needs to be considered in the further developments and authorisation processes of the research infrastructure. The existing planning documents span a time horizon until 2030. Updates that are imminent need to include a future particle collider project in the region. Therefore, the timeliness of deciding for an intent to advance with a construction project or not is important. As the example of the departmental road enlargement in the Nanxy sector has shown, the improvement of mobility can be an opportunity. However, it can also rapidly jeopardise the feasibility of the current scenario when surface site candidate locations are concerned.

**Grand Annecy development project** The regional development around Annecy is captured in numerous planning documents in France with a long-term horizon of 2050. It concerns mobility, management of natural resources, common use of infrastructures and services, preservation of nature and agricultural spaces, support for innovation and energy transition, development of eco-responsible tourism, development of education and training offers, social cohesion and solidarity, and the development of improved joint governance among municipalities, public and private actors, associations, and the public. This development permits the development of synergies with the FCC that for instance is also aiming at the development of innovation, education and training as well as high-quality tourism in the region, in particular in the sectors Groisy and Charvonnex that would host an experiment site. Conflicts could potentially emerge from the increased protection measures.
<figure><img src="image_187.png" /><figcaption>**Fig. 3.54** Overview of the RD903 redevelopment project between the A40 Findrol interchange and the Chasseurs crossroads</figcaption></figure>

**RD903 enlargement and A40 integration** The project to link the A40 autoroute with the 903 departmental road (see Fig. 3.54) and to enlarge this road significantly in the immediate vicinity of the experiment site PD in Nangy was a potential risk for the feasibility. Timely interaction with the Host State administration permitted the development of a suitable solution to adapt the surface site to the road project. Depending on the start date and duration of the road construction works, very good coordination between the two projects is required.

**District heat network in Switzerland** The canton of Geneva has committed<fnref n="12" /> to substantially enlarge its heat distribution networks, in particular with major heat transport axes. The integration of geothermal heat, the GeniLac and the GeniTerre systems ensure heating and cooling capabilities in view of supporting the achievement of climate protection goals. This project leads to concrete synergies with the future research infrastructure that will be able to supply significant amounts of waste heat that can be injected into this network. No conflicts are identified.

**Heat networks in France** Several district heat networks are starting to be conceived and developed in the perimeters of various candidate surface site locations in France. This concerns, but is not limited to, the PA site in Ferney-Voltaire, for example. This development does not generate conflicts, but as the case of Ferney-Voltaire shows, it creates concrete synergy potentials. The network in Ferney-Voltaire today profits from the heat supplied by the Large Hadron Collider. A future particle collider would not only ensure continuity, but would permit a significant

<footnote n="12">¹²https://www.ge.ch/installer-remplacer-chauffage/reseaux-thermiques-structurants-rts-0.</footnote>
increase in the heat supplied. Specific studies of the demand have been carried out in the frame of the feasibility study and these have confirmed this potential synergy.

*Water networks in Switzerland* The regional plans for water treatment in the Geneva region are currently under revision, but details are not available. Although conflicts with the FCC project are unlikely, it is prudent to monitor the evolution of the regional water management plan developments. The raw water for cooling the particle collider may have a high fraction of undissolved residuals after multiple recirculation. It is important to ensure that the residual materials, including the total dissolved solids (TDS) in the cooling water, can and will be accepted by the regional water treatment stations.

*Water networks in France* Similar to the situation in Switzerland, the knowledge of the planning and evolution of the local water networks and water treatment facilities is not centrally available. Although conflicts with the FCC project are unlikely, it is prudent to monitor the evolution of the regional water management plan developments. As mentioned above, it is important to ensure that the cooling water can and will be accepted by the regional water treatment stations.

The water treatment facility in the vicinity of site PD represents an opportunity for the project. The study included the verification of the feasibility of extending the water treatment facility with infrastructures to accept the residual cooling water from the particle collider. In addition, the study revealed that it is, in principle, technically and economically feasible to treat the waste water from the treatment plant and to use it for water cooling systems. This generates a potential to reduce raw water consumption and creates a socio-economic benefit potential for using treated waste water when the particle collider does not need it.

*Railway network development Nord Genève* The existing Léman Express is already reaching its maximum capacity and road traffic saturation calls for further development of the railway infrastructure. The development of a north-south railway transport axis is a priority of the Geneva canton. A conflict with the FCC is unlikely and the additional transport may, on the other hand, lead to potential synergies for the operation period of the new particle collider infrastructure.

*Railway network developments in France* The continuous increase of road traffic, accompanied by traffic saturation and air quality impacts also calls for a development of the railway infrastructure in France in the region concerned by the FCC. This mainly involves the Léman Express lines that pass in the vicinity of some of the FCC surface sites. Therefore, the development of the railway system presents opportunities for the project and potentially for the territory.

*Territorial development in the Dingy-en-Vuache, Vulbens, Valleiry sector* The modernisation of the A40 autoroute in the Dingy-en-Vuache, Vulbens and Valleiry sectors is planned by the operating company ATMB for between 2023 and 2028. It is important that the construction of the FCC starts after the tunnel through the Vuache has been refurbished to avoid limitations. If this is the case, the planned autoroute works do not lead to a conflict with the FCC. However, timely design work must be foreseen concerning the autoroute access for site PD for the FCC construction period. It would take about 10 years to put such access in place.

The territorial developments around local mobility (e.g., bike paths), education (e.g., high school) and emergency services (e.g., fire brigade) represent attractive opportunities to develop synergies with the FCC. Timely engagement with the local, departmental and regional stakeholders is required to leverage the FCC project, support these territorial development projects and integrate them into the surface site activities at PJ.

*Development of Groisy* A school development project was validated by the department of Haute Savoie in 2023. There is no conflict with the FCC project. However, this and related further development projects in Groisy and Charvonnex represent attractive opportunities to generate synergies such as the supply of waste heat, high-quality tourism and the creation of apprenticeship programmes and other cooperation in the education domain.

*Development of Ferney-Voltaire and Geneva international sector* The commune of Ferney-Voltaire has recently launched a large-scale redevelopment and modernisation programme around a new commercial activity zone (ZAC) in the vicinity of the PA surface site (see Fig. 3.55). The supply of waste heat from the existing CERN LHC point 8 (LHCb) site is also integrated in the development of a local district heating network. Developments that create synergies with the Geneva airport are also envisaged in this sector. The plan also foresees the creation of high-tech and innovative facilities and a significant increase in housing capacity. At the same time, on the Swiss side of the border, significant development activities have started in Grand Saconnex. The development of the local tramway system connecting the Geneva international sector (United Nations) with Ferney-Voltaire has been planned.
**Fig. 3.55** The future Ferney Genève ZAC project with an extension of the tram line and terminus located less than a kilometre from the PA site

<figure><img src="image_188.png" /></figure>

All these local economic development activities can potentially create conflicts with the FCC construction activities due to a local concentration of construction sites and construction-related traffic. A timely coordination with the local actors on the planning of an FCC construction is therefore needed.

On the other hand, these developments can lead to significant cross-fertilisation in terms of waste heat supply, mobility, education and economic developments.

## 3.4 Conclusion

The feasibility study phase anticipated studies and field investigations that are part of the environmental authorisation process in both countries. Those include, for example, the establishment of an initial state of the environment, the identification and prioritisation of noteworthy environmental aspects, the identification of indirect and induced connected enabling projects (road accesses, electricity, water and water treatment) as well as informal engagements with the public and their representatives. The scenario development process has been documented together with variants, and evolution of versions, the reference scenario and project invariants.

The studies permitted the identification of relevant issues and points requiring attention. The critical subsurface zones were located and the need for a continuation of subsurface investigations in order to establish a comprehensive and detailed 3D model was identified. The latter will serve as input to the construction process. The results of the preliminary subsurface investigations will provide information about an improved depth and inclination of the tunnel alignment. The initial state analysis revealed that different surface sites are subject to very different environmental constraints and present different opportunities for the creation of synergies. The work on the description of the project elements and the environmental aspects showed that an iterative approach is required due to the long and iterative development of the technical designs. A detailed description of the subsurface construction works is needed as a first step to assess the environmental impacts of the construction phase. A plan for the adequate management of the excavated materials according to industrial best practices and suitable for presentation to notified bodies in both Host States needs to be established as soon as the preliminary subsurface investigation results are available. The particle accelerator requirements need to be formally documented to permit a sufficiently detailed development of the technical infrastructure designs that are needed to assess the environmental impacts.
An eco-design strategy and guidelines have been developed that need to be integrated in subsequent project development by putting a project-wide, transverse systems engineering approach in place.

Although challenges and environmental sensitivities were revealed and documented, no fundamental showstopper with respect to technical, engineering and environmental feasibility could be identified.

The reference locations of the surface sites will require very different optimisation, reduction and integration approaches. Where residual impacts cannot be mitigated with these approaches, compensatory measures may be required. Such measures can differ substantially in terms of type, size and approach among the site locations. For the loss of protected agricultural spaces, a 1-to-1 compensation by re-creating the lost area by transplanting the topsoil to wastelands or areas with poorer quality is envisaged. Rewilding is another way of compensating for the loss of habitats and biodiversity.

Reforestation around surface sites where forests have been removed is an option, along with new forest establishment in previously non-forested areas. Landscape integration and preservation of visibility can be achieved by half-buried site elements, the separation of sites into different segments and by terracing.

The use of decarbonised, including renewable energies, aims at keeping Scope 2 emissions low. Incremental socio-economic benefits can, for example, be generated by entering energy supply contracts and agreements that include the creation of new renewable energy sources and by integrating waste heat recovery and supply from the onset. Location-specific innovation projects can lead to further reductions of the environmental footprint and incremental socio-economic benefits such as the use of treated waste water, the creation of soft mobility infrastructures, the development of high-quality tourism and local services around some of the surface sites and the creation of training and education opportunities in the project as a whole and at individual surface sites.

# Chapter 4

## Sustainability

### 4.1 Context

CERN’s longstanding commitment to sustainability, integrating scientific, environmental, and societal goals, is a guiding principle in the development of a future particle collider infrastructure. The results presented in this chapter show the integration of strategies in the scenario development process that align with the Organisation’s guiding principles and policies, ensuring that the FCC is conceived as a model of responsible large-scale scientific infrastructure development.

From the outset, the studies and developments for the FCC integrated CERN’s existing guiding principles for the protection of the environment. It includes topics that extend beyond the biosphere, covering several aspects of the three sustainability dimensions. Examples include optimising resource use, limiting greenhouse gas emissions, and prioritising sustainable excavation and material reuse. The feasibility study also considered CERN’s ongoing biodiversity and land-use management efforts, ensuring that construction and operational activities respect local ecosystems. It builds on the results and experience of CERN’s past and present energy efficiency and waste heat recovery initiatives, aiming to reduce overall energy consumption, make responsible use of energy and contribute to regional energy networks. Water conservation, noise management, and emissions mitigation are further key elements of the study, reinforcing CERN’s goal of balancing cutting-edge scientific progress with responsible environmental stewardship.

Achieving these objectives requires close cooperation with the authorities in both Host States, as well as meaningful engagement with the public. The feasibility study provides the foundation for the dialogue with national and regional regulatory bodies, ensuring that the FCC project aligns with environmental legislation and sustainability goals in both France and Switzerland. Furthermore, open and continued discussions with local communities will be essential to address concerns, share best practices, and build a collaborative approach to come to an environmental, social, and governance (ESG) framework that can ensure the long-term sustainability of such a new research infrastructure.

By incorporating lessons from past and existing projects at CERN and by leveraging the innovations adopted by other large-scale infrastructure projects in science and beyond, the FCC feasibility study seeks to set new standards for sustainability in large-scale scientific projects. It builds on the principles laid out in international and national laws and regulations, best practices and CERN’s published policies and strategies, integrating best practices in impact avoidance, reduction and mitigation, circular economy principles, and stakeholder engagement. As such, this chapter lays the groundwork for a potential FCC implementation project that not only advances knowledge creation through fundamental physics research but does so with a firm commitment to long-term sustainability that embraces scientific excellence, the environment and society.
<figure><img src="image_189.png" /><figcaption>**Fig. 4.2 Guidance for the sustainability of public investment projects. From Ref. [97]**</figcaption></figure>

<figure><img src="image_190.png" /></figure>

## 4.2 Introduction

### 4.2.1 Sustainable research infrastructures

Research infrastructures (RI) are facilities that provide resources and services for research communities to conduct research and foster innovation [92]. An RI can be a single facility, such as, for example, the European Spallation Source (ESS) or the European XFEL, or it can be a facility that is part of an organisation that hosts multiple facilities, such as the Large Hadron Collider (LHC) and other particle accelerators at CERN (e.g., Antiproton Decelerator, ELENA, PS, SPS) that offer dedicated scientific research opportunities. The Future Circular Collider will be a research infrastructure that is hosted by CERN, conceived and constructed by an international collaboration, providing open access to a worldwide community of scientists.

Sustainability refers to the ability to maintain an activity at a certain rate or level. It integrates three stakes: Society, Economy and Environment (Fig. 4.1). A science programme or project can be considered sustainable if it is able to successfully address and complete its scientific core mission satisfying the requirements of three stakes: it obtains a ‘social license’ to operate [93], it maintains an ecological balance applying an avoid-reduce-compensate sequence [94], and it is affordable in the long term with well-understood and managed risks.

An appraisal process helps understanding if a programme or project is sustainable and provides means to identify pathways to make them more sustainable. This process integrates financial and socio-economic aspects. The latter comprise social and environmental benefits as well as negative effects including environmental costs. The ISO standard for monetisation of environmental impacts (ISO 14008 [95]) and the guidelines for determining environmental costs and benefits (ISO 14007 [96]) are evidence for the importance of applying such environmental unit costs in environmental and sustainability reporting at the organisation and project levels. Science projects can achieve a positive socio-economic net present value. If their financial performance is too low, the funding model needs to be revised. Projects that are financially viable but have no or little socio-economic benefits need to be revised. Projects that are financially and socio-economically positive can be sustainable (Fig. 4.2).
Early and accompanying socio-economic analysis that integrates all sustainability dimensions helps benchmark variants and versions of project scenarios, permitting planning for long-term sustainability. An RI needs to periodically monitor and track the social, environmental, and economic performance against the initial estimations in order to implement a continuous improvement process.

In line with the ‘Ecodesign’ EU Directive 2009/125/EC [17], sustainable development requires proper consideration of all three sustainability elements, including the identification and accounting of positive and negative impacts throughout the entire lifecycle of a programme or project. For RIs carrying out science missions, at least the following stakes should be considered:

*   **Economy**

- Scientific excellence

- Total costs (capital and operation expenditures)

- Risks and residual risks after mitigation

- Direct, indirect and induced ‘value added’ and employment

- Quantified incremental economic benefit potentials

*   **Society**

- Quantified incremental social benefit potentials

- Common good value (the value of the science mission as perceived by people)

- Territorial compatibility

- Social license

*   **Environment**

- Quantified negative externalities

- Quantified incremental environmental benefit potentials

Sustainability also encompasses an *equitable* aspect (see Fig. 4.1). Equity and inclusion are increasingly recognised as essential components for the long-term viability of research infrastructures. They contribute to strengthening the talent pipeline, enriching the diversity of perspectives, and fostering public trust in science. In line with European Commission priorities, the FCC study has integrated equity and inclusion considerations into its sustainability approach. Key elements include:

*   **Support for under-represented regions and groups:** Facilitating participation from less-represented states and disadvantaged communities through training opportunities, mobility schemes, and targeted collaborations.

*   **Engagement with communities as partners:** Moving beyond a one-way transfer of ‘cultural goods’ by fostering dialogue with local populations, cultural institutions, and schools, and by recognising the perspectives and strengths that these communities bring.

*   **Broadening participation in physics:** Embedding diversity, equity, and inclusion (DEI) principles into outreach, recruitment, and cultural engagement strategies to address the exclusionary image of physics and to support the long-term sustainability of the field.

*   **Enhancing societal value:** Ensuring that the benefits of large-scale science projects are broadly shared, thereby reinforcing public legitimacy and demonstrating relevance to society at large.

### 4.2.2 Approach

A new particle collider and its enabling technical infrastructure represent significant long-term investments for participating countries and funding partners. An appraisal process is necessary to gain an understanding of the cost drivers and benefit levers. Reducing the former and developing the latter, along with conceiving a long-term financing model that relies on international collaboration, are required to ensure long-term sustainability from the conceptual phase onwards. Funding agencies, science strategy bodies (e.g., ESFRI), national notified bodies in charge of issuing authorisations and investment banks that potentially grant long-term loans for publicly funded projects (e.g., EIB), request evidence for the project’s viability. The structured process of assessing the case for proceeding with an implementation preparation project and validating the project’s viability is called ‘project appraisal’.

This chapter also compiles a set of regulatory frameworks and appraisal guidelines that exist at the European level, in France and in Switzerland to provide a landscape of the sustainability requirements that govern the planning and implementation of new research infrastructure projects with strategic importance and territorial development needs at CERN. In the countries that are part of the European Research Area (ERA), legal frameworks govern compliance with sustainability aspects. Other countries such as Australia, the UK, and the USA are largely applying panel-based project decision-taking, although the UK does carry out ex-post evaluations on a case-by-case basis, and Australia evaluates the sustainability of research infrastructures periodically. Sustainability and environmental criteria, such as climate considerations, are increasingly being incorporated into proposal design and assessment. Switzerland has recently made sustainability aspects explicit for CERN’s strategically important
projects with territorial development in the update of the law [98, 99] for the encouragement of research and in-
novation that introduces an authorisation process at the federal level. The ‘Ordonnance concernant l’approbation
des plans des constructions et installations du CERN (OCIC)’ [100], the prescription on how this plan for the
authorisation process is to be implemented, has been issued for public review in February 2025. In addition to
the commonly known environmental topics (e.g., air, water and soil) it includes the need for the assessment of the
impacts on the climate and specific measures to comply with climate protection laws.

Consideration of quantitative environmental externalities,<fnref n="13" /> both positive and negative, is still an emerging ap-
proach in the domain of research infrastructures unless it is explicitly required by national legislations and governed
by national guidelines. Such a ‘wider’ socio-economic analysis (as shown in Fig. 4.2) is, however, already com-
mon practice in the general infrastructure project appraisal in numerous European countries such as France [101],
Germany [102, 103], Italy and Switzerland and at EU level through EC funding conditions for numerous sectors,
e.g., Connecting Europe [104], transport [105], energy [106], regional investment projects [107] as well as nature
preservation and restoration [108].

Methodologies for assessing public investment and ensuring that a project contributes to the increase of public
welfare<fnref n="14" /> exist across different policy sectors and institutions [109, 110] including environmental impacts [111] are
already used for research infrastructure projects including particle accelerators like the ALBA light source [112],
the SOLEIL light source [113], the DESY/PETRA III synchrotron [114], the CNAO hadron therapy facility [115],
the LHC [116], High Luminosity LHC (HL-LHC) [117–119] and the Compact Linear Collider (CLIC) study [120].
The Future Circular Collider (FCC) [121] study has, in particular, devoted significant resources to this topic over
a time frame of almost ten years and has contributed to the advancement of the research infrastructure appraisal
process at an international scale through scientific contributions to the field and participation in collaborative
impact assessment projects at EU level. The approach is also used for other science facilities such as the Einstein
Telescope [122], the Paris Saclay heat supply facility [123], the Nantes University hospital [124], and by the Com-
monwealth Scientific and Industrial Research Organisation (CSIRO) [125] to evaluate a number of different science
programmes. Increasingly, research infrastructures, such as the Square Kilometre Array (SKA), are considering
this approach with a view to planning for sustainability [126]. Environmental factors are increasingly being inte-
grated into these assessments [97, 127–129]. As indicated in the 2026 roadmap guide (see page 25 of Ref. [130]), a
comprehensive socio-economic impact assessment is needed when a new research infrastructure project proposal
requests being entered into the European Strategy Forum for Research Infrastructures (ESFRI) roadmap [131].

4.2.3 The context in Europe

Research infrastructure long-term sustainability at European Research Area (ERA [132]) level is primarily guided
by the European Strategy Forum for Research Infrastructures (ESFRI) [133, 134]<fnref n="15" />

EU regulation 2021/695 [135] defining the Horizon Europe Framework Programme for Research and Innovation explicitly includes requirements to address global challenges, including climate change and the United Nations Sustainable Development Goals (SDGs).

EU member states typically translate and integrate the strategies, policies, and guidelines into their national roadmaps and plans in addition to their existing national policies.

A robust long-term vision is a prerequisite to successfully and sustainably operating a research infrastructure.
Therefore, ESFRI issued a number of recommendations and actions [136].

Scientific excellence is the condition sine qua non. However, sufficient funding and sustainable funding models,
required across the entire life cycle, are indispensable for a successful strategy for a new research infrastructure.
Together with adequate human resources, it is crucial for the operational phase. Effective governance is another
key element for ensuring long-term sustainability. Moreover, research infrastructures should contribute to their
sustainability by contributing to their carbon neutrality in order to support the carbon neutrality goals at the
national level. It must be noted that carbon neutrality accounting is being implemented at the national level and
that therefore the application of this concept to international, transnational and distributed research infrastructures
is highly challenging.

While the current recommendations place an explicit focus on scientific excellence, financial sustainability
and societal acceptance, the call for comprehensive sustainability and impact assessment implicitly includes all

<footnote n="13">¹³An environmental externality is a cost or benefit that affects a third party who didn’t choose to incur that cost or benefit, specifically in relation to the environment.</footnote>

<footnote n="14">¹⁴Public welfare refers to the collective well-being of society that is promoted through public services and institutions, aiming to ensure equity, social cohesion, and access to essential goods and services for all. Paraphrased summary from Florio, M. (2019). Public Enterprises: Resurgence and the Future of the Public Sector. Springer.</footnote>

<footnote n="15">¹⁵ESFRI (https://www.esfri.eu) was established in 2002 with the purpose of developing a European approach to Research Infrastructure policy as a key element of the emerging European Research Area (ERA). Further Research Infrastructures contribute to this effort in the frame of the EIROforum and the European Research Infrastructure Consortium (ERIC).</footnote>
environmental aspects. The recommendations also state that RIs should allocate sufficient resources to periodically evaluate and communicate their socio-economic performance to various stakeholders. CERN’s pioneering activities in this domain are explicitly mentioned by the ESFRI guide [137], encouraging national authorities to support the approach in cooperation with experts in the field.

The ESFRI policy brief [138] details the need to tailor the impact assessment to the specific project and requests the inclusion in the roadmap of project proposals that aim for implementation on a ten-year time frame, for which the wider socio-economic impact assessment is provided. Following the OECD definition [139] these impacts comprise “the extent to which the intervention has generated or is expected to generate positive or negative, intended or unintended, higher-level effects”. The European Commission [140] states that “The term impact describes all the changes which are expected to happen due to the implementation and application of a given policy option/intervention [such as investment in a Research Infrastructure and its activities]. Such impacts may occur over different timescales, affect different actors and be relevant at different scales (local, regional, national and EU)”. An ex-post assessment is needed to determine whether the intended objectives and the ex-ante estimations have actually been achieved.

EU Regulation 2021/1060 of the European Parliament and of the Council of 24 June 2021 lay down common provisions on the European Regional Development Fund, the European Social Fund Plus, the Cohesion Fund, the Just Transition Fund and the European Maritime, Fisheries and Aquaculture Fund and financial rules for those and for the Asylum, Migration and Integration Fund, the Internal Security Fund and the Instrument for Financial Support for Border Management and Visa Policy. According to Article 100 of Regulation (EU) No 1303/2013 [141], a major project is an investment operation comprising “a series of works, activities or services intended in itself to accomplish an indivisible task of a precise economic or technical nature which has clearly identified goals and for which the total eligible cost exceeds EUR 50,000,000 [...]”. A socio-economic impact assessment of such major projects is recommended. The European Commission Economic Appraisal Vademecum 2021-2027 [142] captures the general principles and provides sector application examples for impact assessment, including research and innovation in Annex I. It extends and complements the common provisions regulation that recommends cost-benefit analysis in line with EU regulation (EU) No 207/2015 [143]. The methodology is explained in detail in the ‘European Commission Guide to Cost-Benefit Analysis of Investment Projects’ [107].

Climate change adaptation, mitigation, and disaster resilience are covered by this regulation. For instance, the volume of greenhouse gas (GHG) externality.<fnref n="16" />

An analysis of sustainable development (environmental protection, resource efficiency, climate change mitigation and adaptation, biodiversity and risk prevention) should be covered. An analysis of the options, considering technical, operational, economic, environmental, and social criteria for the location of the infrastructure, is requested for a feasibility study. This also describes the project’s consistency with the applicable environmental policy. Considerations should include resource efficiency, preservation of biodiversity and ecosystems, reduction of GHG emissions, and resilience to climate change impacts. The process must comply with Directive 2011/92/EU, which defines the environmental impact assessment (EIA) process, ensuring that projects likely to have a significant environmental impact are subject to an assessment prior to their authorisation. Therefore, the total costs of the negative environmental impacts and their compensation have to be included. Environmental benefits can also be assessed and added. They include, for instance, contributions to improve water supply and sanitation, waste management, energy capacity and stability, transport, ports (airports, seaports, inter-modal), research and innovation, and broadband communication.

The appraisal process aims to assess if a project will contribute to overall social welfare and economic growth, taking into account benefits and costs to society. The EC [107] and UNIDO [144] handbooks focus on economic and societal topics, although aspects such as assessment of the environmental externalities are typically part of project appraisal as required by EU regulation. For instance, the shadow cost of carbon and the GHG emissions are shown in project appraisal examples. Eventually, the requirements for appraisal are defined for each project, specifically by the notified body for that project. For instance, to obtain funds from the European Investment Bank (EIB), a comprehensive appraisal study is required that includes both the positive and negative environmental externalities. The EIB published a guide [145] dedicated to this topic that includes references for the shadow cost of carbon as well as comprehensive calculation examples and guidelines for capturing environmental externalities.

Other requirements emerge, for instance, from applying to the Connecting Europe Facility (CEF). The InvestEU regulation introduces climate, environmental and social sustainability as elements in the decision-making process

<footnote n="16">¹⁶An externality is a cost or benefit that is caused by one party but financially incurred or received by another. Externalities can be negative or positive. A negative externality is the indirect imposition of a cost by one party onto another. A positive externality, on the other hand, is when one party receives an indirect benefit as a result of actions taken by another. The external cost of carbon is explicitly included, and alignment with the EU 2050 decarbonisation objectives is required. Regarding climate adaptation, the costs of measures aimed at enhancing the project’s resilience to climate change impacts, as justified in feasibility studies, should be included in the economic analysis. The benefits of these measures, e.g., measures taken to limit the emissions of GHG or enhance the resilience to climate change, weather extremes and other natural disasters, should also be assessed and included in the economic analysis, if possible quantified; otherwise, they should be properly described.</footnote>
<figure><img src="image_191.png" /><figcaption>**Fig. 4.3**

‘Avoid-Reduce-Compensate’ approach for iterative development of a sustainable project scenario to achieve an ecological balance and, as far as possible, a net gain [13]</figcaption></figure>

when applying for the InvestEU Fund. The process is also a requirement in the framework of the preparatory phase of ESFRI projects. The European Bank for Reconstruction and Development (EBRD) requires project assessment with potentially relevant greenhouse gas (GHG) emissions of more than 25,000 tonnes of CO₂(eq) per year with respect to a baseline of 100,000 tonnes of CO₂(eq) emissions per year. National requirements differ substantially from each other, requiring assessments for investment projects with public funding as low as, for instance, 300,000 euros in Lithuania.

### 4.2.4 The context in France

In France, the ‘Code de l’environnement’ [146] guides the approach to develop a sustainable project scenario in the frame of an environmental evaluation process that is part of the authorisation of the project. The term ‘environment’ is to be understood in its original meaning and in a wide sense: the surroundings and conditions in which the project will be placed.

The goal of the process is to develop a feasible and sustainable project scenario following the ‘avoid-reduce-compensate’ method (French: éviter-réduire-compenser, ERC), which is anchored in European regulations and which is implemented in French law [147]. As a consequence, the project scenario to be authorised aims at a net positive value (see Fig. 4.3).

This approach of iterative development of variants and versions that are continuously improved is also documented in the international standard ISO 14001 concerning environmental management. It describes the Plan-Do-Check-Act (PDCA) model as an iterative process to ensure continuous improvement (ISO 14001, Step by Step, Chap. 1).

Considering that programme and project evaluation in France is compulsory for public investments that exceed 20 million euros and a second assessment is required for investments that exceed 100 million euros, the national assembly tracks and reports on such projects every year using a standard information sheet approach that includes the net present value as an overall sustainability indicator and the greenhouse gas emissions avoided. Such information is published as an annex of the annual budget law [148]. In 2023, 13 research investments underwent comprehensive socio-economic evaluations.

The evaluation concerns the entire project throughout all life cycle phases. It is understood that the level of detail in descriptions for individual phases and project segments can initially differ. The process accompanies the project throughout its entire lifetime. Consequently, the documentation needs to be regularly updated. The process records the initial state of the environment, including nature and a variety of other topics such as urbanism, public health, population safety and economic impacts.

The process actively identifies and assesses the relevant effects on the project environment (environmental impact analysis) and provides input to the design process, following the steps of avoid, reduce, and compensate. The process includes the involvement of the population via, for instance, an informal dialogue and participation phase and a formal public consultation process (‘débat public’) and public inquiry (‘enquête publique’). The latter process is carried out with nationally notified bodies.

To capture sustainability performance properly, the French government requires a socio-economic evaluation for each project funded via public investments of more than 20 million euros. The evaluation must be carried out according to the guidelines of the ‘Secrétariat général pour l’investissement’ (SGPI) [149]. Projects with a total public investment of more than 100 million euros are subject to a second expert assessment, on which the SGPI
provides an assessment to the French parliament and the Prime Minister as well as to the minister under whose
responsibility the project falls.

The socio-economic evaluation comprises a detailed description of the project, its variants and alternatives, the
key characteristics, the implementation schedule, a list of relevant socio-economic indicators, a list of indicator
values showing how the project performs with respect to public policies (e.g., climate impact reduction objectives),
the financial plan, compliance with laws and regulations and a risk registry.

Until 2020, socio-economic evaluations of programmes and projects included only limited environmental aspects
such as habitats and green spaces. The ever-growing importance of more global topics led to a broadening of the
positive impacts and negative externalities covered. The 2023 impact assessment guide in France [149] explicitly
includes all environmental aspects relevant to the project, such as CO2 equivalent emissions, noise, air pollution,
water use and pollution, and soil use and pollution, and requires them to be associated with monetary values and
to quantify the positive contributions in monetary terms. For instance, the legal value of one tonne of CO2 for
the socio-economic evaluation has been set to €32 (base year 2010) in the 2023 guideline, which corresponds to
about €40 in 2024. Despite this value, the annex that indicates the guidelines of converting non-tradeable goods
and externalities into monetary terms indicates a progression of the shadow cost of carbon €250 per CO2(eq) to
2030 and €775 per tCO2(eq) in the year 2050. This progression is in line with the EIB recommendations on the
shadow cost of carbon.

The socio-economic evaluation of the FCC is based on a standard cost-benefit analysis, which reports a net present value and a benefit-to-cost ratio based on the comparison of discounted total costs and benefits over a defined observation period. Costs and benefits were quantified with respect to a ‘counterfactual scenario’ in which CERN operates the LHC until its expected end of life and continues to act as a scientific research platform with the existing particle accelerator complex. Noteworthy positive and negative direct effects and externalities, including environmental effects, were taken into consideration for the entire life cycle of the project.

For the social discount rate (SDR), the 2023 guidelines for socio-economic impact assessment in France [150]
recommend using a value of 3.2% for projects with a lifetime up to 2070. However, for very long-term and low-risk
projects such as research infrastructures, a lower social discount rate in the range of 2.5% can be justified. For the
FCC CBA, economists selected an SDR of 2.8%, based on the weighting of the SDRs in each individual CERN
Member State considering its annual financial contribution to CERN.

If there is a ‘déclaration d’utilité publique’ (DUP), which governs the authorisation process for public investment projects, the socio-economic evaluation is part of the legally required ‘enquête publique’ files to obtain project authorisation.

The socio-economic evaluation has to be updated regularly, following the iterative approach of refining the
project scenario and comparing expected effects to the actual effects once the project is implemented (‘ex-post’
analysis).

A project can be considered sustainable if both the socio-economic and the financial net present value are positive. In addition, the social discount rate applied should be larger than the average weighted cost of the capital needed to finance the project. This can be verified by determining the so-called Internal Return Rate (IRR), which is closely linked to the calculation of the net present value. It expresses at which value of the social discount rate the net present value of the project would become zero. For instance, if the loans for the project are granted at 3% but the net present value becomes zero at only 5%, the condition would be satisfied.

If the project does not generate revenues, i.e., in the case of a research infrastructure for fundamental scientific research, no financial net present value can be provided, a positive socio-economic net present value and an internal return rate higher than the cost of the capital support the sustainability condition. If the socio-economic net present value is negative and the financial net present value is positive, the investment may be financially viable, but it is not recommended from a societal point of view.

4.2.5 The context in Switzerland

The authorisation process in Switzerland is based on guiding principles that require the demonstration of compli-
ance of the scenario with all applicable, individual laws and regulations. All laws and regulations that would apply
to the project need to be identified and explicitly listed. It is considered best practice to follow the Avoid-Reduce-
Compensate approach as required in France and Europe with continuous involvement of notified bodies, public
administration services, and the population. It is to be accompanied by monitoring and continuous improvement
measures.

With the recent update of the law for the encouragement of research and innovation (LERI) [151] and the
development of a dedicated plan for new constructions and installations of CERN [152], guidelines with respect to
the sustainability of research infrastructures become more specific.

The consumption of land, in particular, high-quality crop-rotation arable land that is regarded as a precious
resource, needs to be avoided. Where this cannot be achieved, the residual consumption of such land that is
registered in a national inventory needs, in principle, to be compensated. Therefore, alternatives and variants of
the project need to be documented and assessed. Compensation can, for instance, be achieved by stripping the topsoil of the original land affected and using that soil for creating high-quality arable land within an agreed geographical perimeter, for instance on wastelands or degraded soil. The authorities facilitate the process of identifying suitable compensation areas and administrative processes.

The sector plan for CERN's constructions and installations with territorial needs (PS CERN) [153] highlights a number of topics that need to be considered when developing new projects:

* Water-bearing layers need to be protected and should not be used to provide raw water for cooling purposes. Care must be taken not to pollute water-bearing layers or to mix the water of superimposed water-bearing layers.

* Exclusion buffers next to watercourses protect the habitats.

* Forest clearings are generally forbidden in Switzerland. An exemption can only be granted in exceptional cases for installations that are in the public interest.

* Measures need to be taken to manage rainwater and used water to avoid flooding and polluting the environment. The same holds for the management of water used to extinguish fires.

* Limitations for dust and particle emissions need to be respected.

* Limitations for noise emissions need to be respected. Noise emission limits in Switzerland are absolute and defined for different sensitivity zones as opposed to France, which considers noise limitations in excess of existing background noise.

* Measures need to be taken to manage waste of any kind during all phases of the project.

* The national and cantonal energy and climate protection goals are to be taken into consideration during the planning, construction and operation of future research installations. Energy consumption is to be reduced to a minimum compatible with the capacity to fulfil the scientific research goals.

* The emission of greenhouse gases is to be minimised within the boundaries needed to meet the scientific goals and requirements of the project.

* The design and implementation of technical systems have to integrate the optimisation of energy efficiency and the recovery and use of waste heat. The capacities and characteristics available for internal and external use need to be identified and documented.

* Buildings must comply with the national energy efficiency regulations.

* In general, any optimisation and minimisation effort is understood to be conditioned by the technical feasibility and economic viability. These efforts must always be compatible with the feasibility of achieving the specified scientific research goals.

* A mobility plan that supports the national and cantonal climate plans is to be developed. Parking spaces are to be optimised, in line with the applicable regulations.

## 4.3 Methodology

The study adopted the approach and methodology to carry out a comprehensive, wider quantitative sustainability assessment based on the well-established cost-benefit analysis methodology [154] defined by the European Commission, the European Investment Bank and as described by national guidelines such as the one in France [149]. Such an assessment includes the identification and quantification of costs, benefits, and positive and negative externalities.

The goal is to present an implementation scenario that is likely to be long-term sustainable and for which the sustainability level can be continuously improved with respect to an initial forecast that serves as a baseline. The approach permits the analysis of variants and sustainability boundary conditions to be established.

Following a lifecycle approach, it is a best practice to develop an initial cost-benefit assessment as early as possible at the pre-feasibility stage and to update it regularly as long as the key project features continue to be adjusted during the design phase and even during the implementation. This approach helps address the challenge of exhaustive coverage of costs and benefits, and focuses on gaining a good understanding of the key sustainability enablers and risks.

Sustainability analysis is an ingredient of informed decision-making. The project and sustainability appraisal of the scientific research project do not, however, capture the opportunity and value of the underlying scientific mission. The indicators must therefore not be used to compare research projects or to make an investment choice between several projects.

To be useful during project authorisation, implementation and operation, the project must plan periodic sustainability monitoring and tracking throughout its entire lifetime and implement an iterative improvement process following the standard 'Plan-Do-Check-Act' principle either at the infrastructure level or for new programmes and projects.

Life Cycle Assessment (or analysis) (LCA) [155, 156] is a methodology that is suitable for individual project segments. It enables the assessment of a set of environmental aspects relevant to achieving sustainability. Its
<figure><img src="image_192.png" /><figcaption>**Fig. 4.4** Main socio-economic impact pathways that are sustainability enablers of particle accelerator and particle physics research infrastructures</figcaption></figure>

goal and scope must be well-defined, and its results must be integrated in the overall project and sustainability appraisal. When conducting an LCA, care must be taken to be as specific as possible and to thoroughly document the scenario variant and version assessed, including the assumptions, input parameters, data quality, and allocation procedure (algorithms and tools) to ensure that the results have a meaningful value for appraisal. LCA is unable to capture all relevant environmental aspects and therefore does not replace an environmental impact evaluation. It cannot, therefore, be used to report on the overall environmental performance of a project.

For a comprehensive sustainability assessment, a quantitative Cost-Benefit Analysis (CBA) method based on state-of-the-art economic knowledge that integrates total costs, negative externalities (including environmental ones), industrial, social, and environmental benefits is the preferred and adopted approach. A more complete description of the approach is provided in Sect. 4.5.

Project developers must stay up to date with national and international regulations and legal frameworks during the subsequent design and preparatory phases. They must continuously improve their knowledge of state-of-the-art project appraisal methods and the development of approaches to convert positive and negative impacts and externalities into quantitative terms suitable for reporting an overall sustainability indicator, such as a project’s net present value and benefit-cost ratio. For this reason, as long as additional knowledge and assumptions about the project scenario and its key features are developed, the benefit-cost ratio (BCR) and the internal rate of return (IRR) evolve throughout the lifecycle phases.

## 4.4 Socio-economic sustainability enablers

### 4.4.1 Impact pathways

Socio-economic impact pathways represent a valuable inventory of sustainability enablers. Building on the concept of the ‘Theory of Change’ [157], the EU-funded RI-PATHS project has developed a toolkit [158], linking and coordinating research infrastructures from different scientific domains into a shared network, so that resources and expertise can be pooled and accessed more efficiently. This includes particle accelerator facilities such as ALBA, CERN, and DESY.

The main pathways typical for particle accelerator-based facilities are shown in Fig. 4.4. This section outlines briefly some drivers influencing the pathways that in turn lead directly to benefits and positive externalities.

Future projects are highly encouraged to conduct a comprehensive charting of the impact pathway potentials and develop sustainability-enabling measures in conjunction with such a systematic exploration and design activity.

The following paragraphs outline selected aspects that should be carefully considered during the design, planning, and implementation of a future particle-accelerator-based research infrastructure. They influence directly the generation of benefits in the impact pathway model.

*Sustainability through the creation of fundamental physics knowledge* Science is formalised knowledge that is rationally explicable and tested against reality, logic and the scrutiny of peers, and is a global public good [159]. Ultimately, it is the main output of research infrastructures. In our transforming society, knowledge is poised to become the primary economic resource, gradually replacing capital, land and labour. There is evidence that the
public sector has and continues to fund much of the innovative science that stimulates private sector responses [160]. But what is the value of that knowledge that fundamental science projects generate? Are continued investments in new particle accelerator projects for scientific research sustainable in the perception of those people who do not directly use those instruments and who do not directly profit from the generated knowledge? Which means exist to capture the value of such investments?

Particle accelerators for fundamental science may or may not generate knowledge that can be directly used by society. Other particle accelerators, such as synchrotron light sources, typically serve the needs of applied research. This means that a lower bound for the value of the knowledge generated can be quantified in terms of the cost of publications, the fees charged for facility use, and the resources that users invest in this research. The approach is based on the assumption that research results ultimately lead to products and services that society uses. An example is the characterisation of the COVID-19 virus structure at the BESSY-II synchrotron [161]. Particle accelerators and colliders that serve curiosity-driven research, such as the LHC or the Electron-Ion Collider, cannot use this model since it is not obvious how the knowledge gain leads to direct societal applications. There exists, however, no doubt that the scientific outcomes advance society. This view is shared by the majority of people, even if the asset is not directly used.<fnref n="17" />

Evidence for the validity of the approach is available through the award of several Nobel Prizes in economics for advances in this domain. It is proof that this value generation process is of fundamental importance for society and welfare economics [162–167].

To capture the value that science missions and research infrastructures represent to laypeople who cannot directly use them, methods that originally have been developed to elucidate the public good value of outdoor recreational spaces [168], to identify suitable value levels for environmental protection measures [169], to determine adequate levels of environmental incident mitigation measures [170] and to determine investment levels to protect natural and cultural heritage can be used. This approach has first been taken to estimate the value of the LHC project [171], then for the HL-LHC project [172] and now for the FCC [173]. The approach has recently also been adopted by an atmospheric research infrastructure [174]. Briefly, the value that people associate with a science project can be captured by estimating their willingness to participate financially using well-established approaches in economics, such as contingent valuation, also referred to as ‘stated preference’.

The valuation of non-market impacts is challenging but could be undertaken wherever possible, and the ‘EU better regulation toolkit’ indicates the instruments for it [175]. This will enable a better understanding of the public perception towards the science vision and test the validity of the public funding sustainability hypothesis, i.e., what level of periodic investment is justified in the public perception. To design, plan and carry out a public good value estimation, experts in the domain and qualified companies need to be employed. It is important to ensure that such a willingness to participate in analysis, typically based on surveys, is carried out independently, without the influence of the project owner and according to the internationally established guidelines on ethics and the quality standards required of survey-based analytics. Examples of this approach can be found in Refs. [173, 176].

Depending on the number of countries or funding agencies that would carry out the project, such a survey can require substantial resources. Economists, therefore, use techniques based on the ‘Benefit Transfer Method’ [177] to estimate the perceived value of a large population based on the identification of only a few significant parameters that can be derived from a limited number of samples. These parameters may be different for different projects. Therefore, such a study requires a pilot phase to determine the significant parameters, followed by a mass survey to determine the value that the public associates with the investment.

If the estimated willingness to financially participate (WTP) is larger than the actual or expected contribution to the planned new project, the public good value of the funded infrastructure can be considered consistent with the financial participation and, therefore, can also be considered justified. If the WTP is less than the actual or planned contribution, a discrepancy exists between the value perceived and the contribution supplied. In this case, the project should be revised.

*Sustainability through education and training* Particle accelerators and experimental physics research infrastructures offer the possibility to engage people at all education and training levels, from apprentices to post-doctoral researchers. If people have the opportunity to actively participate in the design, construction and operation of such projects and programmes, they enjoy benefits that translate directly into a 2 to 10% lifetime salary premium [121, 178] compared to their peers who were enrolled in conventional training programmes at schools and universities. A dedicated programme to integrate people after their active time in a research facility into the labour market in their country or region of origin can significantly improve the return on investment for the participating country or region [179].

<footnote n="17">¹⁷The notion for this concept is the ‘public good’ as opposed to the ‘common good’ that is jointly used. Examples of common goods are fish stocks in the ocean and public roads. Examples of public goods include knowledge, natural and cultural heritage, open-source software and datasets, as well as tangible assets such as street lighting.</footnote>