biomass
(6) In this subsection— (A) the term “renewable energy system” means a system which— (i) when installed in connection with a dwelling, transmits or uses— (I) solar energy, energy derived from the geothermal deposits, energy derived from biomass, or any other form of renewable energy which the Secretary specifies by regulations, for the purpose of heating or cooling such dwelling or providing hot water or electricity for use within such dwelling; or (II) wind energy for nonbusiness residential purposes; (ii) meets the performance and quality standards (if any) which have been prescribed by the Secretary by regulations; (iii) in the case of a combustion rated system, has a thermal efficiency rating of at least 75 percent; and (iv) in the case of a solar system, has a thermal efficiency rating of at least 15 percent; and (B) the term “biomass” means any organic matter that is available on a renewable or recurring basis, including agricultural crops and trees, wood and wood wastes and residues, plants (including aquatic plants), grasses, residues, fibers, and animal wastes, municipal wastes, and other waste materials.