(765 ILCS 165/10)
    Sec. 10. Definitions. In this Act:
    "Solar energy" means radiant energy received from the sun at wave lengths suitable for heat transfer, photosynthetic use, or photovoltaic use.
    "Solar collector" means:
        (1) an assembly, structure, or design, including
passive elements, used for gathering, concentrating, or absorbing direct and indirect solar energy, specially designed for holding a substantial amount of useful thermal energy and to transfer that energy to a gas, solid, or liquid or to use that energy directly; or
        (2) a mechanism that absorbs solar energy and
converts it into electricity; or
        (3) a mechanism or process used for gathering solar
energy through wind or thermal gradients; or
        (4) a component used to transfer thermal energy to a
gas, solid, or liquid, or to convert it into electricity.
    "Solar storage mechanism" means equipment or elements (such as piping and transfer mechanisms, containers, heat exchangers, batteries, or controls thereof, and gases, solids, liquids, or combinations thereof) that are utilized for storing solar energy, gathered by a solar collector, for subsequent use.
    "Solar energy system" means:
        (1) a complete assembly, structure, or design of
solar collector, or a solar storage mechanism, which uses solar energy for generating electricity or for heating or cooling gases, solids, liquids, or other materials; and
        (2) the design, materials, or elements of a system
and its maintenance, operation, and labor components, and the necessary components, if any, of supplemental conventional energy systems designed or constructed to interface with a solar energy system.
(Source: P.A. 102-161, eff. 7-26-21.)