# Measuring carbon emissions at the Canada-France-Hawaii Telescope

Nicolas Flagey, Kahea Thronas, Andreea Petric, Kanoa Withington, M.

Johannes Seidel

► To cite this version:

Nicolas Flagey, Kahea Thronas, Andreea Petric, Kanoa Withington, M. Johannes Seidel. Measuring carbon emissions at the Canada-France-Hawaii Telescope. Nature Astronomy, 2020, 4, pp.816-818.
10.1038/s41550-020-1190-4 . insu-04863691

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# Measuring carbon emissions at the Canada-France-Hawaii Telescope

Measuring the carbon emissions of the CFHT in 2019 reveals that the per employee emissions are 16.5 tCO₂e, six times above the recommendation of the Paris Agreement, with ~63% due to the electricity consumption of the summit facility and ~25% to out-of-state air travel. Concerted efforts are underway to reduce this figure.

Nicolas Flagey, Kahea Thronas, Andreea Petric, Kanoa Withington and M. Johannes Seidel

Astronomers may not be the main contributors to climate change or the first to be affected by its consequences: we are not directly burning fossil fuels, and global warming and its associated catastrophes have not substantially impacted observations at ground-based telescopes yet. However, the way of life in the world of astronomy is emblematic of the negative impact of humankind on the climate. We travel to attend meetings all over the world or to execute telescope observations in visitor mode. Our observatories on the ground require a tremendous amount of power to operate. While we look for other habitable planets in the Universe, we should not forget that Earth is the only one proven so far to harbour life, and thus the only one we should be invested in keeping habitable.

Astronomers are eager to think about the best way to address problems. In the context of reducing climate change, we first need to understand what our impact is. To do so, we need to assess our contribution, in terms of greenhouse gas (GHG) emission, to global warming. Ideally, all aspects of our work should be accounted for by using publicly available information and tools to properly estimate the amount of GHG emitted in association with our activities. In this article, we detail the carbon emissions, in tons of CO₂ equivalent (tCO₂e), measured for the year 2019 at the Canada-France-Hawaii Telescope (CFHT) following the method suggested by CarbonBuddy. CarbonBuddy is a Hawai'i-based company whose mission is to empower people to tackle climate change and inequality. It provides web-based tools and services to measure carbon footprints and to take climate actions in the form of offsetting and the implementation of energy-efficiency measures. The CFHT is a 40-year-old telescope on Maunakea, operated remotely from Waimea, on the Big Island of Hawai'i, by a staff of about 45. As with most ground-based observatories, CFHT and other Maunakea observatories

are located away from population centres, but their isolated location in the middle of the Pacific Ocean means that travel and electricity are even more expensive and may have a greater impact on GHG emissions than for other facilities. However, because CFHT operates in queue-service mode, the amount of travel from non-staff to Hawai'i on behalf of CFHT may be reduced relative to an observatory in visitor mode. Observatories are quite different from one another in terms of operations and number of employees, but we think that the analysis presented in this paper can help others in our community and beyond better understand their impact on the climate crisis, and from there, how to address the

global crisis effectively. We invite readers to consult other similar analyses published in this issue for the Australian astronomical community¹, the Max Planck Institute for Astronomy in Heidelberg², or the European Astronomical Society meetings³.

Since the types of electricity sources vary from island to island, we made our emission calculations specific to the Big Island. We then compiled all air travel made on behalf of CFHT between 1 January and 31 December 2019 using the paper expense reports filed after each trip. Each trip is assigned to a region (for example, Europe, US East Coast, and so on) that is represented by a typical flight (for example, Honolulu-Denver-Frankfurt for Europe)

<figure><img src="image_3.png" /><figcaption>**Fig. 1** | Visual breakdown of the carbon emissions at CFHT in 2019. The area covered by each block represents its contribution to the total (749 tCO₂e). Energy-related emissions are in blue, air-travel emissions are in orange, vehicle-fleet emissions are in grey.</figcaption></figure>
in CarbonBuddy to estimate its round-trip carbon emission. We collected monthly bills from three gas companies to derive the amount of gasoline used to refill the company's fleet of vehicles throughout the year. Similarly, we collected electricity bills for the five locations owned by CFHT: the headquarters offices and shop (both of which have solar panels but no storage), two housing locations in Waimea, and the summit facility. The amount of electricity received from the local grid at each location was derived from these bills. All items are then converted into tCO₂e within CarbonBuddy and the total amount of carbon emission made on behalf of CFHT in 2019 was inferred to be 749 tCO₂e, or 16.5 tCO₂e per employee. CFHT serves a large community of astronomers worldwide, and one could thus argue that the GHG emissions estimated here should be divided by the number of users rather than the number of employees. Assessing the amount of emission per capita can indeed be difficult as it may be complex to determine who is ultimately responsible for them. Because the estimated emissions for CFHT could be reduced independently by its leadership and employees, we allocate them to the 45 employees rather than to the larger community of CFHT users.

These carbon emissions are at a level about six times above the goal set by the Paris Agreement (2.7 tCO₂e per person by 2030) in order to limit the global increase in average temperature to less than 1.5°C relative to pre-industrial levels. In addition, the estimated carbon emissions for CFHT in 2019 only include professional contributions: every employee also has personal contributions to their GHG emissions. The breakdown of the analysis (Fig. 1) reveals that almost two thirds of the emissions are due to the electricity consumption for the summit facility (about 1,000 MWh for the whole year, or 469 tCO₂e) and a quarter of the emissions are due to out-of-state travel (about 183 tCO₂e for 94 flights). All other contributions combined only amount to 13% of the carbon emissions at CFHT: 6.4% for the vehicle fleet, 4.6% for the electricity consumption at the headquarters offices and less than 1% for all other contributors. To tackle the issue of climate change, one should then plan on reducing the carbon emissions related to the largest contributors in order of priority. Changing the vehicle fleet to hybrid or electric for instance would lower the carbon emissions for CFHT, but it would only address less than 10% of the carbon-emitting activities, while addressing the electricity consumption at the summit and out-of-state travel would lead to more significant improvements.

Limiting the consumption of electricity at the summit could take multiple forms. First, the observatory could upgrade aging hardware and equipment (CFHT saw its first light in 1979) to be more energy efficient. Then, the way the facility is operated could be optimized to lower energy consumption without impacting the quality of the observations. Finally, the installation of solar panels at the summit, following the example of the Gemini observatory, could directly lower the amount of electricity received from the grid, of which less than 35% is from renewable resources. However, unlike Gemini, the CFHT summit facility does not have a building with a flat roof, and solar panels would need to be installed on the dome itself. Even more ambitious and challenging, the installation of a solar farm could cover all the needs of the observatory. A 540 kW installation (about 2,200 panels of 250 W) would be sufficient and would cover about an acre. Such an installation is small compared to most solar farms, including those being built and planned in Hawai'i (for example, the 30 MW Waikoloa Solar + Storage Project, which will cover 350 acres of land). The cost for the summit installation, which could be built near the mid-level facility of Hale Pohaku, is estimated to range between US$1 and US$4 per watt, depending on the difficulty of the installation and the addition of storage. In sum, the investment could be as high as US$2 million, which would lead to a return-on-investment period no longer than seven years, relatively short compared to the lifetime of an observatory. The farm could even be made larger, and the cost shared by multiple Maunakea observatories. We emphasize here that, at headquarters, CFHT has significantly reduced its electricity consumption over the past six years and installed solar panels. As a result, since 2016, the headquarters buildings at CFHT produce more electricity than they use.

Limiting travel is a problem that we will all face if we want to seriously address the climate crisis. As our analysis has shown, 25% of the carbon emissions at CFHT are due to out-of-state travel, mostly to and from Canada (34 flights) and France (23 flights). Limiting out-of-state travel can take several forms. First, promoting virtual meetings held on behalf of CFHT in lieu of face-to-face meetings would significantly decrease all travel made by CFHT employees, the Board of Directors, and the Science Advisory Committee. In 2019, we estimate that most of out-of-state journeys made on behalf of CFHT were to attend meetings organized by CFHT (such as the users' meeting in Montreal). Promoting virtual attendance to meetings organized by other

institutions and making sure that remote attendance is possible will contribute to changing, as much as possible, the mentality and habits in the field of astronomy, where face-to-face meetings remain the norm. Many meetings have been cancelled, postponed or transformed into fully virtual meetings due to the 2020 pandemic. Lessons will be learned from the virtual meetings about their advantages and disadvantages for our field, and once the pandemic situation is over we may find out that more meetings will promote virtual attendance. Finally, enforcing a cap on the number of allowed out-of-state journeys and annually prioritizing attendance to meetings at the company level could help set a goal in reduction of carbon emissions on a yearly basis.

The investments and changes in habits vary from low to high expense, but all will save operational funds. Lowering the electricity consumption at the summit facility will decrease the CFHT annual bill, which is currently above US$300,000. Limiting out-of-state travel could also save tens to hundreds of thousands of dollars a year, given that such a trip costs at least US$1,000 on average for the plane ticket alone, to which lodging and other per diems are added.

To assess the best path forward, a finer analysis will be required. A better understanding of the power consumption breakdown at the summit is necessary to improve the efficiency of the most inefficient pieces of hardware first. Similarly, analysing the list of meetings that are organized by CFHT or attended by CFHT employees would help to focus on the most important out-of-state journeys and significantly reduce their number below 94.

In addition to this long-term planning and implementation of changes, a short-term solution exists to address the carbon emissions of CFHT: offsetting these emissions with local or worldwide projects. Offsetting usually has a significantly lower cost than the investment required to reduce one's own emissions. However, this process does lower the carbon emissions of the partnered project, and thus that of society as a whole, not that of the individual or company that funded it. Therefore, offsetting is only a short-term solution that needs to be complemented by a reduction of emissions, as explained above. For CFHT, funding the projects listed in CarbonBuddy to offset all the 2019 emissions would range in price from about US$5,000 to US$15,000. The difference in costs arises from the type of project being funded: for various reasons, it is more cost effective to support a wind farm project in China (US$6.5 per tCO₂e) than a reforestation project in Hawai'i
(US$20 per tCO₂e). The offset amount represents a very small fraction of the annual budget of CFHT and could be easily funded by reducing the expenses related to the most carbon-emitting activities, as mentioned earlier. At the time of publication, CFHT has not yet committed to offsetting their carbon emissions.

Ideally, once their carbon emissions have been properly estimated (the main purpose of the analysis we present in this Comment), individuals, events and companies would start by offsetting their carbon emissions with projects, local and global, while working on a longer-term plan to reduce their own carbon emissions. Implementing

that plan takes time, resources, and requires some investments that both pay off in the long run and are necessary if one wants to seriously address the climate change crisis. ☐

Nicolas Flagey¹✉, Kahea Thronas¹, Andreea Petric¹,², Kanoa Withington¹ and M. Johannes Seidel³

¹Canada-France-Hawaii Telescope Corporation, Kamuela, HI, USA. ²University of Hawaii, Institute for Astronomy, Honolulu, HI, USA. ³CarbonBuddy, Kailua-Kona, HI, USA.

✉e-mail: flagey@cfht.hawaii.edu

Published online: 10 September 2020

https://doi.org/10.1038/s41550-020-1190-4

## References

1. Stevens, A. R. H., Bellstedt, S., Elahi, P. J. & Murphy, M. T. Nat. Astron. https://doi.org/10.1038/s41550-020-1169-1 (2020).

2. Jahnke, K. et al. Nat. Astron. https://doi.org/10.1038/s41550-020-1202-4 (2020).

3. Burtscher, L. et al. Nat. Astron. https://doi.org/10.1038/s41550-020-1207-z (2020).

## Acknowledgements

The authors thank K. F. Thronas and P. Keeney, without whom this study would not have been started. The authors also thank L. Dale, C. Castaneda, J. Rodgers, A. Sayco and T. Yost, who have made this study possible by gathering a multitude of bills and expense reports, and all other CFHT employees who contribute daily to making CFHT — and the planet — greener.

## Competing interests

M.J.S. is the creator of CarbonBuddy. The other authors declare no competing interests.