The University of California, Irvine, and Green Mountain College in Poultney, Vt., have been rated as the nation's greenest colleges for 2018.
The two colleges tied for first in Sierra magazine’s annual “Cool Schools” ranking of higher-education institutions with the greatest commitment to sustainability.
Each school received a score of 86.95.
For UC-Irvine, the recognition marks a return to the top of Sierra's list. It ranked first in 2014 and 2015, and has been in Sierra's top 10 in nine of the last 10 years.
It gained the top spot in part because of a net-zero-emission housing construction and a pioneering power-to-gas hydrogen-pipeline injection project, Sierra says.
Green Mountain was recognized for being the second college in the nation to reach carbon neutrality and for pursuing a goal of powering its campus solely via renewable energy by 2020.
Sierra and the Association for the Advancement of Sustainability in Higher Education put together the rankings each year by surveying schools about environmental practices in several categories, including food and transportation systems, water and waste management, purchasing procedures, academics, and investments.
Independent analysts sift through the data and come up with a score for each institution.
For 2018, Sierra received information from 269 eligible colleges.
Here are the 10 higher-education institutions that topped the 2018 Cool Schools list.