Nuclear power is not something we spend a lot of time discussing here at CleanTechnica. When we think of nuclear, we think of Chernobyl, Three Mile Island, and the three-eyed fish featured on “The Simpsons.” On one level, nuclear power has zero emissions — assuming you ignore the massive amount of greenhouse gases created when making concrete containment buildings with walls 12 feet thick or the 10,000 year half-life of many nuclear waste products.
In general, a nuke is like a light switch — it is either off or on. Full power or nothing. That means there are times when it produces more electricity than there is demand for — excess electricity that has to be given away. Sometimes, local operators have to pay others to take the electricity off their hands.
Nuclear power is also slow to ramp up from 0, and so can’t respond to sudden needs for electricity if they aren’t already on.
Researchers at the US Department of Energy Argonne National Laboratory and MIT have put their considerable talents to work on this subject and determined there are ways to make nuclear power generation more flexible. They even suggest that nuclear and renewables could work together to reduce the amount of electricity generated by fossil fuels, thereby lowering the total amount of carbon emissions from the energy generating sector of the economy.
The team explored technical constraints on flexible operations at nuclear power plants, according to Argonne National Laboratory. In a report published in Applied Energy, they introduce a new way of modeling how those constraints affect the operation of nuclear power systems. “Flexible nuclear power operations are a ‘win-win-win,’ lowering power system operating costs, increasing revenues for nuclear plant owners, and significantly reducing curtailment of renewable energy,” the report says.
Jesse Jenkins, a graduate researcher at the MIT Energy Initiative, says the new study “gives us tools to further explore potential benefits of flexible nuclear operations to work in tandem with greater shares of variable sources of renewable power generation.”
Audun Botterud, a principal energy systems engineer in Argonne’s Energy Systems division, says for the first time, “this research evaluates and demonstrates the potential value of flexible nuclear operations in a realistic power system in the United States challenged by high variability in renewable energy generation.”
The study finds that nuclear plants can respond dynamically to hourly electricity market prices and second-to-second frequency regulation needs. Power systems that include renewable energy must be more flexible to balance supply and demand at all times. Nuclear operators in France, Germany and other countries are familiar with this approach, but less so in the United States.
The researchers developed a mathematical representation of the physics-induced operational constraints arising from nuclear reactor dynamics and the fuel irradiation cycle. Then it combined the new approach with power system simulation models to evaluate the overall cost of electricity generation, market prices, and resulting revenues for power plants, assuming different levels of nuclear flexibility.
“Nuclear power plants are governed by a different set of principles compared to other generators, and our approach enables the representation of these relationships in the analysis of power systems and electricity markets,” said Francesco Ganda, the principal investigator of the project and a principal nuclear engineer in Argonne’s Nuclear Science and Engineering division.
By being flexible, plant operators can lower overall operating costs in the power system. For example, operators could generate less nuclear power whenever renewable energy is widely available. Nuclear plants could then exploit their spare capacity to sell valuable “operating reserves,” or the ability to quickly change power output to help grid operators rebalance supply and demand when unexpected events occur, such as power plant failures or errors in demand forecasts.
This flexibility could increase the profitability of nuclear plants by increasing revenues from electricity markets and reducing variable operating and maintenance costs. Overall, nuclear plant flexibility can also help integrate more wind and solar resources and reduce production of fossil fuel-fired energy and related carbon dioxide emissions.
The result of the research is that nuclear power plants could act more like rheostats rather than on-off switches. We may not like the idea of building new nuclear power plants for any number of reasons, not the least of which is that they take decades to construct and cost gigatons of money. Those resources could be better applied to adding more renewable energy capacity. You can get several times more electricity from renewable power than nuclear power from the same investment.
But existing nuclear plants will be with us for decades longer. The thought of nuclear and renewables ganging up on fossil fuel generation to lower total carbon emissions is one that should make any good environmentalist smile.