What energy can nuclear power beat

You have to be very convinced of a technology to deface an Elvis song out of love. "Can't Help Falling in Love with U", sing a few dozen activists in front of a university building in Amsterdam, while shaping their hands into a U, the symbol of uranium. The YouTube video comes from the "Environmental Progress" association, which is committed to a renaissance of nuclear power. The activists recently held a "Nuclear Pride Fest" in Munich to celebrate nuclear fission and to call for new reactors to be built.

For decades, nuclear power was the great enemy of the environmental movement. But this front is no longer as closed as it was before. Groups like "Environmental Progress" or the so-called "Eco-modernists" no longer see nuclear energy as an ecological evil, but as a solution to environmental problems. Unlike the combustion of coal or gas, for example, the splitting of atomic nuclei does not cause any carbon dioxide emissions and is therefore essential to slow down global warming.

The most prominent proponent of this thesis is Bill Gates, who recently met with members of the US Congress to convince them of the benefits of atomic energy, such as those Washington Post reported. In an open letter to employees late last year, Gates wrote: "Nuclear energy is ideal for combating climate change because it is the only CO₂-free, scalable energy source that is available 24 hours a day." The problems with current reactors - such as the risk of accidents - could be solved with innovations.

Gates' efforts should not be entirely altruistic. The Microsoft founder owns the company TerraPower, which researches new types of nuclear reactors. According to Gates, he intends to invest a billion US dollars in the technology and attract a further billion from private donors - plus, if possible, receive government support. A group of scientists in the specialist magazine recently asked for more funding Science. It is a serious mistake to shut down nuclear power plants, they argue - because then greenhouse gas emissions would rise even more. "We should keep the existing nuclear power plants and rethink how new plants can be built."

"Nuclear power is the only technology that is becoming more and more expensive"

But expanding nuclear power would be an extremely risky investment. "The fundamental problem is cost," says a recent report from the Massachusetts Institute of Technology (MIT) on the future of nuclear energy. While renewable energies such as photovoltaics or wind power have become cheaper and cheaper over the last few decades, new nuclear power plants have become more expensive at the same time. Nuclear fission currently provides around eleven percent of the world's electricity. The MIT researchers have calculated the costs of nuclear energy for several regions, with a clear result: As far as generation is concerned, wind and photovoltaics are practically always cheaper than nuclear energy, even with optimistic assumptions for nuclear power. To make them competitive again, a lot would have to happen. The MIT scientists propose to lower the regulations for nuclear power plants, i.e. lower the safety standards. In order to make the systems cheaper, components would have to be manufactured as if on an assembly line and prototypes of novel reactors would have to be placed next to one another in huge "reactor parks" in order to test them there more quickly.

In view of disasters like Chernobyl and Fukushima, lower safety standards and testing grounds for immature reactors are unlikely to be conveyable in many places. The standardization of power plants, for example through the development of the so-called "European pressurized water reactor" (EPR), has not yet brought the expected savings: three reactors of this type are currently under construction in Europe, in all three cases - in Finland, France and Great Britain - Costs and construction time exceed the original expectations. Construction work in Finland has been taking almost ten years longer than planned. According to calculations by Greenpeace, the British facility at Hinkley Point C is likely to cost 108 billion euros in subsidies over a period of 35 years.

"Nuclear power is the only technology that is becoming more and more expensive," says Frank Peter, deputy director of the Agora Energiewende think tank. Peter not only questions new nuclear power plants, but also the extension of operating times for old reactors, as is currently being discussed in the USA, for example. Allowing reactors to run ahead of schedule for only 20 years usually requires expensive modernization in order to keep aging technology in good working order. "Even these investments often make no economic sense," says Peter. It is true that it is a problem if nuclear power plants are replaced by fossil energy sources such as coal or gas. But wind and sun could just as easily fill this gap.

The International Energy Agency (IEA) has investigated how much nuclear energy could actually contribute to saving the climate. In order to limit global warming to two degrees, global emissions would have to drop from 37 billion tons today to below 5 billion tons by 2050. According to the IEA, the largest proportion of this reduction, almost 40 percent, can be achieved by better energy efficiency, i.e. more efficient use of energy. Renewable energies could contribute a third. In this scenario, nuclear power would have a share of five percent. "Even for this, around 1,000 nuclear power plants would have to be built," says Manfred Fischedick from the Wuppertal Institute for Climate, Environment and Energy. Compared to today, that would be a tripling of the number of reactors. "A gigantic order of magnitude to make a minimal contribution to the climate," says Fischedick.

The running wave reactor should get by with burned-out fuel rods from other power plants

In order to get the cost and safety problems under control, many nuclear power proponents hope for new developments. For example, Bill Gates' nuclear company TerraPower is working on a so-called running wave reactor, which is supposed to get by with spent fuel rods from light water reactors or depleted uranium. The concept for this dates back to the 1950s, and the technology has not yet got beyond basic research. It is known that the reactions require temperatures of more than 500 degrees Celsius, which is a heavy load on the material and requires cooling from liquid sodium - risk factors that have hardly been researched.

According to TerraPower, it is aiming for a functioning prototype by the mid-2020s. Even then, there would still be a long way to go to a finished nuclear power plant that supplies electricity. In terms of time horizon, such reactors are comparable to nuclear fusion, believes Fischedick: It may work at some point, but it hardly helps with the current problems. "By the time a power plant of this type is in operation on a large scale, we must have resolved climate change long ago. We cannot wait for that."