Power from wind and solar waxes and wanes with the breeze and sunshine, not in response to when it is most needed. 
Credit Gordon Welters/ The New York Times

Germany has spent $200 billion over the past two decades to promote cleaner sources of electricity. That enormous investment is now having an unexpected impact — consumers are now actually paid to use power on occasion, as was the case over the weekend. (emphasis added)

Power prices plunged below zero for much of Sunday and the early hours of Christmas Day on the EPEX Spot, a large European power trading exchange, the result of low demand, unseasonably warm weather and strong breezes that provided an abundance of wind power on the grid.

Such “negative prices” are not the norm in Germany, but they are far from rare, thanks to the country’s effort to encourage investment in greener forms of power generation. Prices for electricity in Germany have dipped below zero — meaning customers are getting […]