California has adopted an aggressive Renewable Portfolio Standard requiring 20% of all energy delivered come from renewable resources by 2010. The State Legislature is considering increasing this goal to 33% by 2020, requiring approximately 10,000MW of incremental renewable energy capacity to meet 2020 demand.  Developing the renewable resources necessary to achieve these benchmarks will be challenging for several reasons: material costs have risen dramatically; electric transmission remains inadequate, siting new lines is extremely difficult; and technology breakthroughs are needed to manage costs, deal with reliability concerns and continue to improve efficiency.