We must move away from fossil fuels to reduce carbon emissions. But to achieve this goal, it is not enough to increase investment in clean energy. We also have to think more flexibly and creatively about which energy is clean.

In addition to the traditional renewable energy sources Robert Pollin focuses on—solar, wind, and geothermal—nuclear power warrants a place in a realistic clean energy program.

Nuclear should be an option because traditional sources face significant constraints. Solar and wind technologies generate power that is difficult to store. As a result, they can’t provide consistent, always-on power at the scale we need. And because large-capacity geothermal is feasible only near tectonic plate boundaries, its potential is limited.

While renewables are developing, nuclear power is an established technology that can provide large amounts of cheap, stable, carbon-free electricity. Nuclear reactors already generate 42 percent of the world’s carbon-free electricity, and 64 percent in the United States. This large market share is possible thanks to nuclear’s low generation costs compared to fossil fuels. Favorable economics make nuclear power the world’s best option for replacing coal plants.

Developing safe nuclear technology is the best way to help the planet.

Yet nuclear power does raise safety and environmental concerns, which lead Robert Pollin, and many others, to dismiss it in the effort to reduce carbon emissions. However, nuclear technology is not stuck in 1970, and new advancements can solve many of the longstanding deficits of conventional designs.

The biggest barrier to sustainable nuclear energy is nuclear waste, which remains radioactive for hundreds of thousands of years. A conventional light-water nuclear reactor, varieties of which have been used around the world for decades, generates about 20 metric tons of high-level nuclear waste each year, for a total of about 9,000 metric tons worldwide.

If waste is such a big problem, why has it taken so long to fix it? The answer is that light-water designs have worked well enough: they are sufficiently safe, cheap, and clean that there has not been much incentive to improve—until now. Global warming is the crucial incentive we need to revolutionize nuclear power and to increase funding for the commercialization of new designs.

An enormous amount of innovation is already happening. There are designs for new reactors that are passively safe, meaning that even in the event that a power failure prevents cooling, they cannot melt down. Such designs were built and operated as far back as the 1960s, but that was well before the accidents at Three Mile Island, Chernobyl, and Fukushima, and before the threat of climate change became a reality. There was no push to commercialize them. Fukushima, in particular, has spurred the adoption of designs with passively safe components. A large fraction of new reactor construction in recent years, both domestic and foreign, has used Westinghouse’s AP1000 reactor, which can passively cool its core for up to seventy-two hours after loss of power. This design and others like it, called Generation III+ reactors, are considered the new industry standard, and they will likely form the basis of the majority of new reactor construction as old plants reach the end of their operating lives over the next twenty to forty years. There is also a great deal of research on more sophisticated passively safe designs, which can cool indefinitely, fully shutting themselves down after power loss.

Even more important, new reactor technology can produce significantly less waste, or even use it as a source of fuel. Some current designs extract energy from uranium more effectively, producing only a fraction of the long-lived waste of conventional plants. Other, more experimental, systems extract the energy left behind in long-lived waste, reducing its radioactive lifetime by an astonishing factor of a thousand—from hundreds of thousands of years to only hundreds of years. This second approach is especially valuable because even the waste from conventional reactors can be used to generate a tremendous amount of energy. Worldwide, there are about 270,000 metric tons of spent nuclear fuel from sixty years of commercial use; specially designed reactors can turn that waste into enough electricity to power the globe for about seventy years—even taking into account increasing demand. This technology exists today. We just have to implement it commercially.

Many nuclear engineers, myself included, were driven to their work by a commitment to environmentalism. We think developing safe nuclear technology is the best way to help the planet. And we hope nuclear power will earn its rightful place in the clean energy revolution.