District energy systems can use a variety of conventional fuels such as natural gas, coal, or oil--whichever fuel is most competitive at the time. Many district energy systems are transitioning to all or partial use of a local resource, including:

• Waste wood in downtown St. Paul
• Oat hull by-products at the University of Iowa
• Landfill gas at the University of California Los Angeles
• Tire-derived fuel from shredded, waste automotive tires at the University of Missouri - Columbia

This keeps energy dollars re-circulating in the local economy and may qualify for a renewable energy production tax credit or for the renewable energy portfolio standard. Some district energy systems are finding ways to utilize other natural sources of thermal energy, such as deep lake water cooling or geothermal. Additionally, many district cooling systems incorporate thermal storage systems to further expand peak capacity and increase the operational flexibility.

Content Courtesy of International District Energy Association