In March, the California Public Utilities Commission (CPUC) authorized the use of tradable renewable energy credits (TRECs) for use in the California Renewables Portfolio Standard (RPS) program. The RPS program requires investor-owned utilities, energy service providers, and community choice aggregators operating within the state to obtain 20 percent of their retail sales from renewable energy sources by 2010. Last week, the CPUC stayed its March decision on the use of TRECs, backtracking after hearing complaints from investor-owned utilities and developers that the new TREC rules were too strict.