Solar power in California includes utility-scale solar power plants as well as local distributed generation, mostly from rooftop photovoltaics. It has been growing rapidly because of high insolation, community support, declining solar costs, and a Renewable Portfolio Standard which requires that 33% of California's electricity come from renewable resources by 2020, and 60% by 2030. Much of this is expected to come from solar power via photovoltaic facilities or concentrated solar power facilities.