Climate change puts nuclear energy into hot water

Long regarded with suspicion because of radioactivity, nuclear power suddenly has a revived image, thanks to the idea that many more plants could be built without worsening global warming. Unlike power plants fired by coal and natural gas, nuclear fission produces no carbon dioxide, the main greenhouse gas.

But there is a less well-known side of nuclear power: It requires great amounts of cool water to keep reactors operating at safe temperatures. That is worrying if the rivers and reservoirs which many power plants rely on for water are hot or depleted because of steadily rising air temperatures.
If temperatures soar above average this summer – let alone steadily increase in years to come, as many scientists predict – many nuclear plants could face a dilemma: Either cut output or break environmental rules, in either case hurting their reputation with customers and the public.

Governments and the energy industry are just starting to grasp the vulnerabilities of water-hungry power plants. If the complications prove serious in countries where inland sources of water are growing scarce, where seafront nuclear stations are unwelcome or impractical and where alternative cooling technologies are too expensive, it could take the bloom off of nuclear as a source of clean energy and leave it more unclear than ever where sizable new power supplies might come from.

“We’re going to have to solve the climate-change problem if we’re going to have nuclear power, not the other way around,” said David Lochbaum, a nuclear engineer who is with the Union of Concerned Scientists.

“As the climate warms up, nuclear power plants are less able to deliver,” he said.

France relies on nuclear power more than any other country and is held up by advocates of nuclear power as a model for how to generate enough cheap and reliable electricity to sell surpluses abroad while reducing carbon dioxide emissions. But global warming is exposing France to new risks.

In countries like Australia, where the government is considering introducing nuclear power, and the United States, which gets about a fifth of its electricity from nuclear power, some officials and operators warn of similar pitfalls if plants are built in areas where there already are water shortages.

Finding enough water for nuclear plants “is front and center of everything we will do in the future,” said Craig Nesbit, a spokesman at Exelon, a Chicago-based company operating the largest group of U.S. nuclear plants.

Officials at Electricite de France have been preparing for a possible rerun of a ferocious heat wave that struck during 2003, the hottest summer on record in France, when temperatures of some rivers rose sharply and a number of reactors had to curtail output or shut down altogether.

The French company operates 58 reactors – the majority on ecologically sensitive rivers like the Loire.

During the extreme heat of 2003 in France, 17 nuclear reactors operated at reduced capacity or were turned off. Electricite de France was forced to buy power from neighboring countries on the open market, where demand drove the price of a megawatt hour as high as €1,000, or $1,350. Average prices in France during summer months ordinarily are about €95 per megawatt hour.

International Herald Tribune