The Museum currently offsets 100% of its electricity and natural gas use with Green-E certified Renewable Energy Credits (RECs), in addition to facility based systems that employ renewable energy and reduce energy expenditures.    

Air Conditioning

The Museum utilizes a chiller/thermal storage system, which keeps the buildings climate cool in the warmer months and ensures proper humidity for the collections year round.  The system works by producing ice during evening hours when citywide demand for energy is lower.  The ice is placed in thermal storage containers and water flow introduced.  Air is blown around the containers and then circulated through the building during the day.  This reduces the Museum’s impact on the region’s grid system and prevents brownouts, as air conditioning usage is highest during mid-day.  

Solar Power

The Museum has a 99.4 Kilowatt photovoltaic solar array on its roof.  An average residential solar array is between 2 and 4 Kilowatts, so the Museum’s is pretty substantial.  In fact, when it was installed in 2002, it was the largest solar array in Illinois.  You can see the Field Museum's solar array producing electricity in real-time here.  For more information, there is an article in “Energy Seeds,” a blog maintained by the Illinois Clean Energy Foundation. 

Interested in learning more or getting involved with the push for clean, renewable energy?  Please visit the websites of local advocacy organizations:

Midwest Renewable Energy Association (MREA)

Illinois Solar Energy Association (ISEA)


When the Museum was built in 1921, there were six light wells that provided solar lighting throughout the building.  Over the years, these light wells were covered over to provide more storage for the Museum’s vast collections (the Museum has approximately 30,000,000 specimens!).  However, natural lighting still almost exclusively lights the largest and busiest hall in the Museum, Stanley Field Hall. 


Chandeliers in Stanley Field Hall during transition to energy efficient bulbs.  Incandescent on the left, new LEDs on the right.

Additionally, the Museum has seen an energy savings of up to 40% with these modifications:
• Replaced inefficient incandescent light bulbs with LED lights.  Of the 20,000 light fixtures in the museum, 6,700 have already been converted.  LEDs are 5 times more energy efficient than incandescent bulbs and last for several years.
• Utilized motion sensitive lighting, which illuminates the display only when someone is present to view it (Northwest Coast Native American Hall and Cyrus Tang Hall of China).