Cost of photovoltaic has dropped 99% since 1977

The price of solar photovoltaic cells has dropped 99% in the past quarter century. So in an increasing number of markets around the country, solar is at or very close to grid parity.

Consider Colorado. The Denver Business Journal reported last month the results of months-long competitive bidding process:

Xcel Energy Inc. is proposing to triple the amount of utility-scale solar power on its grid in Colorado, and add another 450 megawatts of wind power