In each standard rate offered by a utility for purchases of energy from a qualifying facility, the electrical registration for billing purposes can be accomplished by two options.
Under this metering configuration (see ILLUSTRATION A), each meter, with detents, will register the cumulative noncoincident energy and/or demand over the billing period. Whenever the qualifying facility generates electricity the coincident generation is consumed on-site, thus reducing the energy and/or demand registered by meter M1. Any excess energy and/or capacity not required by the qualifying facility will be delivered to the utility and registered by meter M2. The individual meters will separately record all energy delivered to the utility by the qualifying facility and delivered to the qualifying facility by the utility.
Ill. Admin. Code tit. 83, § 430.70