It's been decades since the last nuclear power plant was completed in the US, but the increasing emphasis on avoiding carbon emissions has led the Obama administration to promote an expansion of nuclear power. Partly as a result, there are now 19 sites for potential new plants in the licensing and approval stages, and the Department of Energy has been awarding loan guarantees with the intent of getting some of these projects off the ground. With that as a backdrop, Nature is publishing a pair of commentaries today on whether nuclear power should have a significant future in the US energy economy.

For what are ostensibly opposing views, the two pieces actually agree on a wide variety of the basic facts; the difference is primarily in the meaning they assign to those facts. One of the big points of agreement is that nuclear plants are ferociously expensive, and they take years to build. The fragmented nature of US utilities means that relatively few of them have the financial muscle to take on a project like a nuclear plant on their own. As a result, nuclear plants will either rely on private financing or the sorts of loan guarantees provided by the DOE.

And that's a problem; even the pro-nuke piece notes, "From past experience, the default rate for loans on US nuclear plants may be as high as 50 percent, potentially leaving taxpayers to cover up to $18 billion of the $36 billion in loan guarantees [that the Obama administration has asked for]." With that sort of default rate, it's also very, very hard to attract private financing.

Not surprisingly, the anti-nuke piece suggests we simply shouldn't bother. Nuclear power is too expensive, and the costs of renewables like solar and wind, which come primarily from manufacturing and not deployment, have been dropping rapidly. The authors estimate that, before the decade is out, these will be the cheapest forms of power generation in the US, beating even coal.

The intermittent nature of these sources can be handled by existing technology like compressed air and pumped hydro, so we don't even need to develop anything new, and concentrated solar with molten salt storage will be a reality within years, regardless.

In the pro-nuke piece, the authors note that the full costs of these intermittent sources should include the construction of a more distributed, smarter electric grid that can better balance power fluctuations. (Presumably, the opposition would point out that we could probably benefit from this sort of grid regardless, but didn't have the space to do so.)

But, more generally, they simply work on the assumption that significant amounts of baseline power will be needed, and nuclear is currently the lowest-carbon source. Our existing baseline infrastructure of coal and nuclear plants is aging fast, and we'll have to replace it with something—and that something should probably be nuclear.

To handle the finances, the pro-nuclear crowd suggest going ahead with loan guarantees regardless of the risks, and allowing mergers of utilities to enable them to build plants without outside financing. To make the huge costs of plants more appealing within the energy economy, they also call for a carbon tax to make the coal's externalities more apparent in the market. A streamlined approval process would also help; the authors point to the fact that South Korean companies can complete the construction of a new reactor within four years, which would significantly cut construction costs.

If the cost of a better electric grid is a huge externality for renewable energy sources, the anti-authors point out that nuclear has a few big externalities of its own. They point out that the insurance pool for nuclear plants could only cover $11 billion dollars of damages, and a major accident could easily exhaust that. With the closing of the Yucca Mountain facility, the waste storage problems also remain unsolved. Waste isn't considered in the pro-nuke piece at all, while even its authors recognize that "nuclear power poses substantial risks; an 'inherently safe' nuclear plant simply doesn’t exist."

The anti-nuclear piece also brings up the risk of proliferation, but the argument seems specious in the context of a discussion of US policy. It may be an issue in the global energy economy, but as the example of Iran demonstrates, there's little that policy can do if a country is sufficiently determined to get access to the materials needed for nuclear weapons.

Confused yet?

The dueling opinions are enough to give readers a case of mental whiplash. The safest thing to say is that neither of the alternatives advocated here—nuclear and renewables—are going to be quite as good as their advocates suggest. So, in an attempt to provide some perspective on this, we'll wade in with our own opinion.

There are benefits to a smarter grid with more on-grid power storage no matter what, so we probably want that, regardless; building it shouldn't necessarily be counted against the cost of renewable power.

That said, most of the best sites for solar and wind are pretty remote, so there is a real cost to linking them to the grid that has to be considered. Costs have come down dramatically as manufacturing capacity has expanded, but it remains very small, and solar and wind still contribute only tiny fractions of the US energy supply. We'll build and install a lot of renewables in the next decade, but there's simply no way we can build enough to meet our needs, especially given the number of coal and nuclear plants that will need replacement.

So we'll want to build some nuclear plants, and we'll need to start them now if we hope they'll be in place in a decade. Whether these are economical will largely depend on the regulatory environment. Right now, that looks very bad. The Yucca Mountain experience suggests that, even decades after the Three Mile Island accident, the public still isn't at ease with nuclear power, while the failure of any climate legislation shows that the carbon taxes that might help nuclear compete with coal are unlikely to be put in place.

So, chances seem good that the nuclear plants in the planning stages aren't going to do very well in economic terms. Regardless, they can provide a key source of power to help bridge us to the point where we can make enough hardware for renewable power generation, and plug it into a grid that's prepared to handle it.

Nature, 2010. DOI: 10.1038/467391a (About DOIs).