Nuclear - critical choice for 2050
by Matthew Wald, Nuclear Energy Institute
January 14, 2019
As the urgency of the climate crisis becomes more obvious, nuclear power is drawing another look. The power sector needs to develop to meet climate targets. Renewables (RES) have taken significant share of the energy mix in recent years but going further means securing far more investment and solving the complex challenge of integrating variable power. There is a need for alternatives to run alongside RES, keeping us on track. Matthew Wald from the Nuclear Energy Institute (Washington) makes the case for nuclear as an essential part of a clean energy future.
Nuclear energy provides well over half the non-emitting electric energy in the United States. Nuclear displaced 547 million metric tonnes of carbon dioxide in 2017, the last full year for which data are available. Hydro was second at 203 million metric tonnes, wind at 175, and solar at 37 million metric tonnes.
More dramatic is what happens when a nuclear plant closes. In the United States, it has generally been replaced by a mixture of natural gas and wishful thinking. Vermont Yankee, a 42-year-old boiling water reactor near the Massachusetts border, was replaced entirely with gas two years ago. New England was, and still is, negotiating to bring in replacement hydropower from Quebec, but has been unable to reach agreement on the necessary transmission lines. As a result, carbon emissions in the year following the shut-down jumped by 2.5 percent. To mitigate against the effects of climate change, they should be falling by that amount each year.
Credit due on climate
The way government has structured the electricity markets not enough credit is given for nuclear power’s contribution to climate stability. As a result, we’ve seen this shift to natural gas in the United States, because the price of methane is down by approximately 75 percent over the last 10 years, the result of hydraulic fracturing in shale (“fracking”). This is not a climate solution; gas produces about 55 percent as much carbon dioxide as coal when burned at the end of a pipeline, or more if it is liquefied, shipped and re-gasified.
At the moment, five nuclear plants in the biggest power market in the United States, called PJM, are scheduled to close. Together they produce more electricity than all the wind and sun added in the region in the last 25 years.
Fresh eyes, fresh support
The mathematical realities are beginning to sink in, in new places. The Boston Globe said recently in an editorial that Massachusetts, its home state, was going to have trouble meeting its ambitious carbon goals because of two nuclear plant closures. The Union of Concerned Scientists, a group better known for its scepticism about nuclear, recently said that the “sobering realities” of climate change “dictate that we keep an open mind about all of the tools in the emissions reduction toolbox—even ones that are not our personal favourites”—including nuclear. Google, trying to match zero-carbon generation to its 24/7 server farms, attributed part of its success to nuclear power on the grid.
Framing the discussion as a choice between nuclear and renewables is not helpful. Even if wind and sun were a replacement for nuclear energy (and recent experience is that they are not), why are we even talking about deciding between the two? Replacing zero-carbon nuclear with zero-carbon wind or sun does nothing to reduce carbon.
There is an adage in American English called the Rule of Holes. It says that when you find yourself in a hole, the first rule is to stop digging. The climate problem is urgent, there is no faster solution than preserving existing nuclear in the intermediate term, the next 15 years or so. The next step is to pursue more.
Nuclear’s capacity factor far better than RES
Solar and wind are growing but it’s important to use the right metric to measure them, which means taking account how often they run. A megawatt of nuclear, preserved or built, produces far more energy than a megawatt of sun or wind.
The reason is capacity factor. Capacity factor means looking at the production that would result from full output, 24/7, for a year, compared with actual output. U.S. nuclear plants have capacity factors in the range of 92 percent. On-shore wind runs at about 30 to 40 percent, and sun, outside desert areas, around 15 percent. So 1,000 megawatts of nuclear capacity produces about 2.5 times more carbon-free electricity in a year than 1,000 megawatts of wind, and about six times as much as 1,000 megawatts of solar.
Variable RES a headache for grid stability
An additional challenge for solar and wind is that they produce on their own schedule. In the U.S., this does not mesh well with peak demand which is mostly driven by weather. Peak air conditioning is in late afternoon, when the sun is too low in the sky to produce much energy. Wind produces mostly at night, but that’s generally a low-demand period.
Meanwhile, solar growth is producing big surpluses, which is a sign that the grid faces limits on how much electricity it can successfully integrate from intermittent sources.
In California as an example, energy prices are often pushed far below zero, so customers in neighbouring states are getting paid to take California’s surplus energy. Surplus wind produces negative prices in the American Midwest. As wind and solar grow, the fraction of their production that is unusable will rise.
And as Joshua S. Goldstein and Staffan A. Qvist put it in their recent book, “A Bright Future: How Some Countries Have Solved Climate Change and the Rest Can Follow,”prices may fall but value may fall faster. Electricity costs from solar panels might be 3 cents a kilowatt-hour, which is wonderful if the market price is higher than that. But if the solar surplus has pushed prices to zero or lower, it doesn’t matter what the price to produce it was. “A cheap ice cream cone in a remote desert would be a bargain, but 1,000 more would be worthless unless you had a freezer,” they write.
The problem gets worse as policies push the system towards 100 percent renewables. Build enough solar to supply a system in the short days of December and January, and the waste in June and July will be enormous.
Don’t assume storage is the answer
Energy storage can help manage the fact that solar and wind production don’t synchronise with demand. But nearly all the storage in the United States is still pumped hydro, and it’s very difficult to build more of that, for environmental reasons.
California will use batteries to help manage the afternoon transition when the sun goes down too low to be useful, and there is a scramble to start up gas generators. But the Tesla “Mega-battery” in South Australia, at 129 megawatt-hours, is said to be the world’s largest, but it stores an amount of energy that a large nuclear plant produces in six or seven minutes. More batteries will be built but their price at present doesn’t make them practical for bulk storage. It’s much cheaper to back them up with combustion turbines running on natural gas, which are not very carbon-efficient.
The price of batteries will go down, but decreases are constrained in part by the cost of raw materials. We can all hope for breakthroughs, but this problem hasn’t been solved yet.
Climate stabilisation is not the only reason for retaining and building reactors. Nuclear power reduces the output of mercury, soot, and the pre-cursors of ground-level ozone, or “smog.” And being near a fully-fuelled reactor is far more secure than sitting at the end of a very long natural gas pipeline.
Nuclear is evolving
Nuclear technology is evolving. Existing reactors are operated much more efficiently than thirty years ago and the reactors running today, and new models, will use more robust fuel. Some new reactors will take advantage of factory fabrication. Others will get away from the light-water models we’ve used for 50 years, and operate at lower pressures but higher temperatures, making their heat more efficient and useful. Designs that will enter the market in the 2020s will be better at tailoring their output, to mesh better with varying demand and varying production from intermittent sources, as nuclear complements the attributes of wind and sun.
As we consider the future, we must bear in mind that decarbonisation, to the extent we achieve it, is going to mean using more electricity. Home heating, heavy industry and transport will all need to be converted to electricity. And with all the work required to build batteries, manufacture electric cars, sell them to the public and build a charging infrastructure, how much more effective is all of that if they are charged with zero-carbon energy, not from a mix that is heavy on fossil fuels. And if Hydrogen turns out to be the fuel of choice for EVs – nuclear can provide that too. Zero-carbon electricity will give electric cars more bang for the buck. “Bang for the Euro” doesn’t have the same ring to it, but it’s just as true.
How sustainable is nuclear?
Unlike fossil fuels, sustainability isn’t an issue for nuclear. MIT said in in a 2011 study that “There is no shortage of uranium resources that might constrain future commitments to build new nuclear plants for much of this century at least,” and that was not counting the possibility of nuclear recycling or breeder reactors. And the study was published before a breakthrough in recovering uranium from seawater, which vastly extends uranium reserves. Beyond that there is thorium, and other technologies. And nearly all energy technologies rely on mining minerals from the earth, many of them with constrained supplies. This includes building solar panels and wind turbines.
Matthew L. Wald is Senior Communications Advisor at the Nuclear Energy Institute, Washington, US, Twitter: @mattlwald