Climate Change May Hurt Electric Generation

Scientific American:

Ironic twist alert: most electricity production requires vast amounts of water. Cold water. Which means that climate change is going to be bad for electricity supplies.
Why's that ironic? Here's how we make electricity. In the U.S., we burn coal or natural gas, which produces massive quantities of the greenhouse gases causing climate change, or we fission uranium. The heat from those processes boils water that makes steam that spins a turbine. And those turbines produce more than 90 percent of our electricity.
Massive cooling towers then help chill the power plant back down using river water, for example. Only river water isn't quite as cold as it used to be, or as available. As a result, in recent years, such thermal power plants in the southeastern U.S. have had to decrease power production because river temperatures were too high or water levels were too low.
That problem is only going to get worse, according to an analysis in the journal Nature Climate Change. By the 2040s, available electricity could be down by 16 percent in the summertime.

I can understand water levels being too low, but water temperatures being too high?  Didn't know that.