Pennsylvania’s Alternative Energy Portfolio Standards Act (AEPS Act) 1 requires that a certain percentage of the electric energy that electric distribution companies (EDCs) and electric generation suppliers (EGSs) sell to retail customers be derived from qualifying alternative energy sources. EDCs and EGSs must meet certain minimum thresholds for the use of energy generated by: solar photovoltaic technologies, Tier I sources (including wind, fuel cells and biomass), and Tier II sources (including distributed generation systems, demand-side management and municipal solid waste). 2 Consequently, the rules defining a qualifying alternative energy source are very important. Most of these rules are set forth in the AEPS Act and its implementing regulations.