Twenty buildings were chosen for the pilot from approximately 270 Yale buildings based on their carbon footprint, building and budget types, and data quality. These 20 buildings were stratified into four treatment types of five buildings each and the remaining 250 buildings were placed into a control group. The control group did not participate in any pricing scheme and did not receive additional information or engagement. The four treatments groups were information, target, redistribution, and investment.

Throughout the six-month pilot, each of the 20 pilot units received a monthly utility report which included metered energy use and cost information. Yale applied a $40 per metric ton of carbon dioxide equivalent (mtCO₂e) carbon price based on the federal government’s estimate of the Social Cost of Carbon (SCC). The pilot included all direct greenhouse gas (GHG) emissions (Scope 1) and indirect GHG emissions from the generation of purchased energy (Scope 2). While the buildings’ representatives received a bill for carbon on their monthly energy report, they did not incur the charges until the end of the pilot. The buildings were not allowed to purchase carbon offsets to reduce emissions at a carbon price lower than the $40 cost set by the Carbon Charge Task Force.

We analyzed the results of this pilot in order to answer three primary questions related to the current effectiveness of the Carbon Charge Project pilot.

1. What was the relative impact of various factors on the change in emissions for buildings during the pilot?

We found that it may be more difficult for larger buildings to reduce their emissions and, conversely, it may be easier for energy intensive buildings to reduce their emissions. Our results indicate that bigger buildings had a harder time reducing their emissions than smaller buildings, and units that are more energy intensive were able to reduce their emissions by more than units that had a smaller baseline energy use.

2. Did instituting a carbon charge, no matter the design, influence the emissions of participating Yale buildings?

All treatment groups that participated in the Carbon Charge experienced a statistically significant reduction in emissions relative to their baseline. These results are positive for the Carbon Charge Program at Yale, justifying their efforts at instituting a price on carbon in order to decrease campus emissions.

However, emissions for all Yale buildings, not just those that participated in the pilot, decreased relative to their baseline. This could be due to the fact that the winter during the 2015-2016 academic year was warmer on average than the previous five winters, and all units used less energy for heating.

3. Which was the most successful carbon pricing scheme at achieving emission reductions?

Our results conclude that investment in spending on self-guided energy actions led to the greatest emission reductions. Given that the Investment scheme was found to be associated with the greatest reduction in emissions relative to the other treatment groups and the control, we sought out the administrators for the five business units in that treatment to investigate what actions that took to reduce their emissions. We found particularly interesting results from La Casa Cultural and Stoeckel Hall.

La Casa Cultural (301 Crown Street) used funds from the Carbon Charge Investment scheme for signage around the building to communicate energy efficiency practices, such as turning out the lights, closing  windows, and utilizing recycling bins.

Stoeckel Hall converted manual light switches to motion activated ones in restrooms and public areas, as well as reducing heating requirements by adjusting set points as to not heat areas unnecessarily late in the evening.

For F&ES, Kroon Hall was included in the redistribution scheme during the pilot program. During the pilot, F&ES worked on technical solutions to reducing the building’s energy use (such as adjusting the occupied hours of the building and installing a thermal curtain in one office space). In addition, a communication strategic plan was created that included using social media, email, articles, and video interviews to discuss the Carbon Charge and improve its educational value to the community. Due to these efforts, Kroon Hall reduced emissions by 17 percent relative to our baseline for a total rebate of $630.90. This rebate went towards the F&ES Environmental Stewardship Committee to further energy reduction efforts on campus.

In the end, the university’s pilot found local illustrations of many issues observed in global efforts to price carbon, namely, that carbon pricing design and implementation is complex, administratively challenging, and politically sensitive. While there is still much to study and learn, the Carbon Charge pilot now provides a framework for others to develop carbon pricing models within educational institutions and more broadly across other sectors, all of which collectively aim to achieve a low-carbon economy.

Overall, it appears that the Yale Carbon Charge is effective at reducing emissions, and is therefore a critical component of Yale’s strategy to meet its goals outlined in the Yale Sustainability Plan 2025.