Solar & Wind Just Passed Another Big Turning Point. By Tom Randall, Bloomberg News, 10/6/2015. "It has never made less sense to build fossil fuel power plants...the virtuous cycle has begun. For the first time, widespread adoption of renewables is effectively lowering the capacity factor for fossil fuels.
That's because once a solar or wind project is built, the marginal cost of the electricity it produces is pretty much zero—free electricity—while coal and gas plants require more fuel for every new watt produced. If you're a power company with a choice, you choose the free stuff every time.
It’s a self-reinforcing cycle. As more renewables are installed, coal and natural gas plants are used less. As coal and gas are used less, the cost of using them to generate electricity goes up. As the cost of coal and gas power rises, more renewables will be installed."