People in Germany got paid to turn their lights on over Christmas, but it's not as weird as you might think.
For parts of Sunday and Monday, power prices fell below zero, thanks in part to warmer-than-normal weather and a stockpile of wind power on the grid. Below-zero prices have happened over 100 times this year.
Germany has spent hundreds of billions of dollars on renewable energy over the years. When prices fall below zero, it means that power supply exceeds power demand.
The problem is, the grid can't handle all of that excess. And "inflexible" power sources — like plants that run on coal — don't shut off and on quickly enough to respond to volatility in energy supplies.
That's why Germany has to pay people to use up power and take some stress off the grid.
Of course, this doesn't mean power companies are handing wads of cash to consumers. The New York Times reports negative prices just means utility bills are lower.