Droughts and Nuclear Power Plants

Anti-nukes and pro-nukes are stuck in the same muddle. For decades, anti-nukes have been tossing up reasons not to use nuclear energy and pro-nukes have been batting them down. Both sides have run out of things to talk about.

So, Associated Press ran a story that warned nuclear plants could face power decreases or even shutdowns because droughts have lowered some stream flows. That indeed is a concern, and it applies every bit as much to fossil-fired plants. It's just curious that AP chose to mention only nuclear power plants.

Not having much to talk about, anti-nukes crowed that "Water is the nuclear industry’s Achilles’ heel. You need a lot of water to operate nuclear plants. This is becoming a crisis."

This is silly, of course, because there are alternate ways to cool power plants. In most cases, the problem is that stream flows are so low that adding waste heat would raise the stream temperature unacceptably. The solution is to add cooling towers. What's the penalty for doing that? The US Department of Energy did a study of all the thermal (fossil and nuclear) plants in the US. They found that if 100% of the power plants in the US (except in the Southwest) that rely on stream water were retrofitted with wet cooling towers, the energy penalty could be as high as 3%, but only during the hottest 88 hours of the year.

In an extreme situation, stream flows could be so low that wet cooling towers couldn't be used because of the water consumption. In that case, dry cooling towers can be used. Then, the penalty could be as high as 10%, again during the hottest 88 hours of the year. The authors didn't attempt to evaluate conditions for plants that were designed for dry cooling, but acknowledged that the penalty would be lower. Probably, the penalty would be about the same as for the ten percent of plants best suited for retrofit, which is about 1%.

As we look into the future, we can see that as long as new plants are designed to accommodate cooling towers, the penalties will be minimal.

In the meantime, as small as these penalties are, even they can be avoided most of the time. When stream flows are adequate the cooling towers can be bypassed. And when they are operated, it'll be unusual that the plants have to rely entirely on them; the cooling load can be shared between the cooling tower and the stream, or between a wet cooling tower and a dry one.

But the best solution will be to use the waste heat productively, as industrial heat or for heating homes and businesses. The waste heat can even be used for air-conditioning, by use of absorption chillers.

So drought and low stream flows won't be a hindrance to nuclear energy in the future. That means nuclear power plants will be able to provide backup to wind and solar energy.