The term “combined heat and power” means the generation of electric energy and heat in a single, integrated system, with an overall thermal efficiency of 60 percent or greater on a higher-heating-value basis.

The term “district energy systems” means systems providing thermal energy from a renewable energy source, thermal energy source, or highly efficient technology to more than 1 building or fixed energy-consuming use from 1 or more thermal-energy production facilities through pipes or other means to provide space heating, space conditioning, hot water, steam, compression, process energy, or other end uses for that energy.

The term “energy sustainability” includes using a renewable energy source, thermal energy source, or a highly efficient technology for transportation, electricity generation, heating, cooling, lighting, or other energy services in fixed installations.

The term “institution of higher education” has the meaning given the term in section 15801 of this title.

The term “institutional entity” means an institution of higher education, a public school district, a local government, a municipal utility, or a designee of 1 of those entities.

The term “renewable energy source” has the meaning given the term in section 918c of title 7.