PA: On December 16, 2004, Governor Edward Rendell signed into law Pennsylvania’s Alternative Energy Portfolio Standard, requiring that qualified power sources provide 18.5 percent of Pennsylvania’s electricity by 2020. There are two tiers of qualified sources that may be used to meet the standard. Tier 1 sources must make up 8 percent of the portfolio, and include wind, solar, coalmine methane, small hydropower, geothermal, and biomass. Solar sources must provide 0.5 percent of generation by 2020. Tier 2 sources make up the remaining 10 percent of the portfolio, and include waste coal, demand side management, large hydropower, municipal solid waste, and coal integrated gasification combined cycle.