“We need to better understand these composite effects,” said Michael Craig, an expert in energy systems at the University of Michigan, who recently led a study that looked at how rising summer temperatures in Texas can place unexpected strains on the grid. “It’s an incredibly complex problem to plan.”

Some utilities take note of this. After Superstorm Sandy unplugged 8.7 million customers in 2012, utilities in New York and New Jersey invested billions in flood walls, diving equipment, and other technology to reduce the risk of failure. Last month, New York City’s Con Edison said it would include climate projections in its planning.

When the freezing temperatures hit Texas, a breakdown in one of the two reactors at a nuclear power plant in South Texas that supplies 2 million households triggered a shutdown. The cause: The sensor lines connected to the plant’s water pumps were frozen, said Victor Dricks, a spokesman for the Federal Nuclear Regulatory Agency.

It is also common for extreme heat to disrupt nuclear power. The problem is that the water used to cool reactors can get too warm, which can lead to shutdowns.

Flooding is another risk.

After a tsunami in the Japanese power plant Fukushima Daiichi in 2011 led to several collapses, the US Nuclear Regulatory Commission asked the approximately 60 decades-long nuclear power plants in the US to assess their flood risk in order to take climate change into account. Ninety percent presented at least one type of flood risk beyond what the facility was designed for.

The greatest risk was in heavy rain and snowfall, which exceeded the design parameters for 53 turbines.

Scott Burnell, a spokesman for the Nuclear Regulatory Commission, said in a statement: “The NRC continues to conclude, based on staff review of detailed analysis, that all US nuclear power plants are appropriate to potential flood events, including the effects of climate change Can handle and stay safe. “