# Assessing the Carbon Intensity of e-fuels Production in European Countries: A Temporal Analysis
###### Abstract
Directive 2018/2001 (RED II) [14] defined RFNBO as fuels produced from renewable energy and requires greenhouse gas emissions savings from their use of at least 70% compared to the fossil fuel comparator of 94 gCO\({}_{2}\)eq/MJ. Two delegated regulations on RFNBOs set out the detailed rules for their production and the methodology for calculating emissions savings: EU 2023/1184 [16] and EU 2023/1185 [17]. The corresponding framework, represented in Figure 1, introduces the three essential pillars aiming at ensuring that hydrogen is effectively produced from low-carbon electricity:  
* Additionally: The aim is to stimulate the deployment of new renewable electricity generation capacities and avoid competition with other uses of renewable electricity;
* Temporal correlation: The aim is that RFNBO production takes place at times when electricity is produced
* Geographical correlation: The aim is that RFNBO production takes place in grid areas where renewable electricity is produced. The criteria for RFNBO production make sense from a GHG emissions perspective by using additional electricity when and where it is available. The regulation EU 2023/1184 proposed a flexible application of the criterion to temporal correlation in the initial phase. From 1 January 2030, the temporal correlation condition requires the production of the RFNBO during the same 1-h period as the renewable electricity production. Until 1 January 2030, the temporal correlation condition shall be considered complied with if RFNBO is produced during the same calendar month as the renewable electricity. Regulation EU 2023/1185 sets the methodology to assess and calculate the life cycle GHG emissions savings. These two regulations are part of a wider context where hydrogen and derived fuels are expected to become one of the main pillars of the EU decarbonisation strategy as a clean solution for mobility, power generation, and industrial applications, according to the European Green Deal (EGD) [19]. In order to promote renewable hydrogen production, the European Commission adopted \"A hydrogen strategy for a climate-neutral Europe\" in 2020 [20] by setting targets for the installation of at least 6 GW of electrolysis powered by renewables in the EU by 2024 and 40 GW by 2030. The EU also recently proposed the REPowerEU plan [21] for rapidly reducing the dependence of the EU on fossil fuels by accelerating the green energy transition. RePower EU considers renewable hydrogen as key to replacing natural gas, coal, and oil in hard-to-decarbonise industries and transport. Thus, hydrogen can be used to replace fossil-based hydrogen for transport and industrial processes and new industrial products, such as green fertilisers and steel. REPowerEU proposed a target of producing 10 Mt of hydrogen using electrolysis within the EU, which we expect to be equivalent to 60 to 70 GW of electrolysis capacity that has to be installed in the EU by 2030; another 10 Mt of renewable hydrogen will have to be imported by the EU in 2030, according to REPower EU. Hydrogen can be used to produce liquid synthetic kerosene or other synthetic fuels to decarbonise the aviation and maritime sectors, in addition to other uses. While technological solutions are emerging, the European legislative framework requires the saving of at least 70% of GHG emissions to avoid a simple shift of transport-related pollution from fossil-based internal combustion engines to power plants generating the electricity used for e-fuel production. Even though electric, hydrogen or e-fuel vehicles are sometimes promoted as zero-emission or climate-neutral by considering only tailpipe emissions, the production of both the vehicles and the energy used to power them is not burden-free [22; 23]. This is why performing a life cycle analysis (LCA) and a systemic analysis [24; 25; 26] is necessary to ensure that the environmental impact is effectively reduced and not simply shifted to another stage of the system or another environmental impact [22]. Many LCAs of electric, hydrogen, or e-fueled vehicles already exist.