Wind and solar energy have come a long way in the last decade and are now competitive with fossil fuels in a large percentage of the world. An analysis by investment bank Lazard estimates that as of last fall, the cost to build an industry-leading solar plant ($50 to $60 per MWh) or wind farm ($32 to $77 per MWh) was less than building a gas combined cycle ($52 to $78 per MWH) or coal plant ($65 to $150 per MWh).