food for thought, via ARS

Nuclear energy has been struggling. Aging reactors are being shut down, a process accelerated after the 2011 Fukushima disaster, and new reactors aren’t being built. Even the exceptions bend more toward the rule in the US, where recent reactor construction was abruptly halted following the 2017 bankruptcy of reactor maker Westinghouse.

But many believe that total decarbonization of the energy sector can’t fully happen without nuclear power. And decarbonization must occur in the near future if we want to have a shot at mitigating the effects of climate change. Nuclear power’s advantages are that it suffers none of the variability of wind and solar power, and the energy it produces is essentially carbon-free, (although, of course, uranium fuel is generally mined and processed in ways that emit carbon dioxide). Nuclear power plants are also capable of supplying huge amounts of power to the grid, which is a boon as the global population keeps growing.

At the juncture of nuclear’s sad present predicament and its apparent necessity in the future, a new, 270-page report from the Massachusetts Institute of Technology (MIT) details what it would take for nuclear energy to see a renaissance.

Valuing the absence of carbon emissions

One way to make nuclear competitive with other kinds of power plants, MIT says, is by linking the cost of building new nuclear power plants to carbon emissions.

Currently, the electricity sector of the global economy releases 500 grams of CO2 per kilowatt-hour generated (gCO2/kWh), on average. If we want to limit the effects of climate change, MIT says, CO2 emissions from the electricity sector need to fall to 10–25 gCO2/kWh. Renewable energy can take us part of the way there, but in a heavily decarbonized world, adding more wind and solar generation to the grid will eventually become extremely expensive for each new unit of those kinds of energy added to the grid.

In that future scenario, grid operators have to add grid-scale batteries in massive quantities or undertake large-scale transmission line buildout to make sure there’s always power on the grid. That’s where nuclear comes in. The expense of building nuclear power plants becomes viable “when the allowable carbon emissions rate is reduced to less than 50 gCO2/kWh,” MIT writes.

In this future, nuclear finally has an opportunity to under-bid more common forms of zero-carbon electricity. In an extremely solar- and wind-saturated environment, nuclear energy may be the more reasonably priced zero-emissions energy source.

Of course, the future is unknowable, and if battery costs decrease dramatically, nuclear loses its edge. MIT writes that “nuclear energy’s advantages decreased notably” in scenarios where battery storage prices fell “far beyond” the prices currently projected for 2050.

The scenarios run by MIT also assume that anything will be done about carbon dioxide releases. Fossil fuel-based sources of electricity have prices that don’t fully account for the cost of adding extra carbon dioxide to the air. If fossil fuel users aren’t made to pay for the external costs of climate change, then they’ll continue to underbid nuclear in a significant way.

Besides waiting for a world where zero-carbon electricity is valued for its avoided emissions, another path to reducing nuclear’s cost lies in cutting the cost of building a nuclear power plant. Currently that cost is extraordinary, MIT writes, due to inexperience, extremely custom plant designs, regulatory issues, and financing issues.

Materially cutting costs

According to the report, the costs of building nuclear power plants have only increased over the recent decades, unlike the costs of the construction of other forms of electricity generation, which have become cheaper. In part, that’s because nuclear reactor construction requires specialized skills that are employed over years on one project. Nuclear power plants are also only built rarely, so there’s less opportunity to develop more people with specialized skills.

To halt the increase in construction costs and start bringing build prices down to earth, MIT’s researchers looked to other high-capital, highly engineered facilities—like chemical processing plants and oil refineries—and recommended several main branches of attack on nuclear’s construction price.

The first approach to cutting costs has its roots in the troubles that plagued the unfinished Summer and Vogtle plants in South Carolina and Georgia. There, contractor disputes escalated over the years, morphing into sprawling lawsuits over who promised what.

MIT says that before investors go in on a nuclear project, more of the project design needs to be intricately detailed. Sub-contracting manufacturers and builders also ought to be approved ahead of time and included in the design process to make sure that “systems, structures, and components are designed for efficient construction,” and everyone is on the same page in terms of standards. In addition, a single primary contract manager should be the point person for all additional subcontractors, the report states.

The report also says there’s room to cut costs on nuclear power plant buildout by standardizing the process more thoroughly. Multiple reactors at large nuclear sites should be prioritized so that less permitting and customization of a site needs to happen. The report writes that “the most cost-effective plants have been built with multiple (up to six) units per site using a standardized design… with the same vendors and workers working on each unit, and with a continuous build.” This also helps labor learn on a first unit and work more efficiently on subsequent units.

Importantly, the report didn’t conclude that a more advanced reactor technology necessarily needs to be designed and adopted, MIT wrote, although new reactor technology could potentially offer efficiencies that Light Water Reactors (LWRs) can’t offer.

Instead, the nuclear industry needs to improve “how the overall plant is constructed.” Accelerating construction time also incurs less interest on the project owner’s financing, which is an important source of cost increases on delayed nuclear power plant construction.

A politics game

Another part of the reason nuclear construction is so lacking today may be attributed to political will: nuclear disasters may be few and far between, but when they do happen, they’re dramatic and cause people to be uprooted from their homes for years (if not forever), not to mention hundreds of billions in cleanup costs incurred by the power plant owner or the government of the region that plant serves.

There are ways to mitigate risk, though. Today’s reactors are better designed to resist meltdown. The latest reactors “include engineered safety systems that require no emergency AC power and minimal external interventions,” the MIT report notes (that’s in contrast to the decades-old reactors at Fukushima, which melted down after a tsunami shorted its electrical power, thus disabling its cooling system). Reactors with passive cooling systems have already been put in place in the US and China. “These design attributes will make plant operations much simpler and more tolerable to human errors, thereby reducing the probability that severe accidents occur and drastically reducing offsite consequences in the event that they do,” MIT writes.

One major issue that MIT does not take into account is the issue of spent nuclear fuel storage. “While these issues are universally considered barriers to the expansion of nuclear energy use, the political dimensions of finding solutions to waste disposal and managing proliferation risks far outweigh the technical challenges,” the report notes.

Even in the absence of political will to build new nuclear power plants, the report argues that old power plants that are not yet past their prime should be subsidized by the US government to continue running. This is an interesting argument that has echoes in the Trump administration, although MIT and the US government have different reasons for advocating for nuclear subsidies.

The Trump administration has tried to convince energy regulators that nuclear and coal power plants should be subsidized or compensated additionally because they offer baseload power (that is, you can dispatch electricity to the grid from these plants whenever you want, and you can store fuel on site). This reasoning has been rejected by federal regulators, who say that the market is appropriately compensating power generators already for contributing electricity to the grid.

MIT, however, suggests that older nuclear plants should be subsidized (forget the coal), because existing plants offer low-cost zero-emissions power. The report notes that “in the United States, nuclear plants with a combined capacity of 20 gigawatts have operating deficits of less than $12 per megawatt hour, which suggests that a credit of this amount should be enough to keep these plants open.”

“Twelve dollars per MWh is a low premium to pay for low-carbon electricity,” MIT writes. “For example, it is much less than the cost of current subsidies used to incentivize additional wind generation.”

A subsidy from the Trump administration that helps both coal and nuclear likely would not help nuclear as much as a nuclear subsidy alone could, because coal and nuclear are competitors offering the same product. Coal would continue to outbid nuclear in a world without a serious cap on carbon. But a world with much more stringent CO2 emissions restrictions seems far off at the moment. While headwinds are against nuclear, the recommendations mapped by MIT give a sense of where the industry would need to go to see a revival.