Written by Caleb Tomlin, Principal Team Leader - Nuclear Beyond Electricity
Today, most of the nuclear reactors in the world serve a singular purpose: the consistent, continuous generation of large amounts of electricity, referred to as baseload electricity production.
A typical nuclear reactor today uses light water as a moderator and coolant, produces more than 1 GW of electricity, and operates more than 90% of the time. In the U.S., 93 reactors provide about 20% of all electricity and more than half of all carbon-free electricity. In comparison, France operates 56 reactors which generate about 70% of the country's electricity.
Building profitable new baseload nuclear plants now presents greater challenges and investment risks, and the U.S. has only completed two new nuclear reactors in the 21st century. The average reactor age nationally is around 42 years.
Because of this, there is great interest in using nuclear technologies to serve purposes other than baseload electricity production, which could open new revenue streams for improved competitiveness and help to decarbonize more of the energy landscape beyond electricity.
Energy Beyond Electricity
Several countries around the world – including the U.S. – have committed to reaching net zero emissions by 2050. Achieving this will require decarbonization of other energy sectors beyond electricity.
According to the U.S. Environmental Protection Agency, electricity production was responsible for about 25% of domestic greenhouse gas emissions in 2021. It’s important to note that even if electricity production were completely decarbonized, 75% of emissions would still remain.
For example, transportation produced 28% of U.S. greenhouse gas emissions in 2021, industry produced 23%, commercial and residential use produced 13%, and agriculture produced 10%. Currently, these sectors are largely served by fossil fuels, and opportunities to decarbonize them vary significantly.
Applications of Nuclear Energy Beyond Electricity
Pursuing applications other than baseload electricity production can help nuclear reactors have greater decarbonization impact while opening significant new revenue streams.
Some of the most promising applications for nuclear beyond electricity are:
- Hydrogen production
- Heat production
- Water desalination
- Energy storage & flexibility
To varying extents, both traditional reactors and newly designed advanced reactors could accomplish each of these goals. But for now, less than 1% of energy produced by nuclear reactors is used for applications other than electricity.
Nuclear plants, particularly those with advanced reactor designs, could be used for cogeneration, or the generation of both electricity and another product, such as heat or hydrogen. Advanced reactors may also have siting advantages that could allow them to be sited closer to industrial facilities and end users, improving their competitiveness.
One EPRI model predicted that an additional plant revenue stream of $15/MWh, whether from a carbon-based production credit or the sale of a non-electricity product such as hydrogen, could be the most impactful way to make nuclear plants operate more competitively in today’s market. More information is available in the freely accessible report 3002011803.
Hydrogen Production
Nuclear energy has long been considered for hydrogen production as a promising pathway to increase profitability and decarbonize other energy sectors beyond electricity.
For example, the Energy Policy Act of 2005 reflected a significant push to create a hydrogen economy in the United States by securing a domestic hydrogen supply and developing technologies such as fuel cells to decarbonize the transportation sector, which has historically relied heavily on fossil fuels.
How Hydrogen Production Works
There are several proven methods to produce hydrogen. These processes require large amounts of heat, electricity, or both. Today, hydrogen production relies on energy intensive processes that produce about 830 MTCO2 per year.
Hydrogen that is generated from carbon-free sources is called green hydrogen. As a fuel, hydrogen reacts with oxygen to produce water and no carbon emissions are released.
The high temperatures provided by nuclear reactors can create a favorable environment for thermochemical water splitting or high temperature electrolysis to produce large quantities of green hydrogen.
One advanced reactor type is particularly well suited for this purpose. High-temperature gas reactors (HTGRs) can have outlet temperatures above 700°C which can be used to split water and generate green hydrogen.
Advantages of using Nuclear for Hydrogen
Currently, electric cars are one of the only technologies available to decarbonize transportation. Green hydrogen, on the other hand, could be used as a liquid fuel to one day replace fossil fuels in heavy shipping, airplanes, and trucks, which cannot be powered by electricity as easily.
Hydrogen could also be used to generate fertilizers, helping decarbonize industrial agriculture products. Producing hydrogen domestically would also improve energy independence.
Hydrogen could replace fossil fuels in electricity production, such as coal and natural gas plants. Recently, the Los Angeles Department of Water and Power committed to replacing 4300 MW of fossil fuel plants with 100% green hydrogen by the 2030s.
Economic hydrogen transport remains a significant challenge. An economy of scale could significantly lower hydrogen costs by constructing both production and transportation infrastructure as well as establishing greater demand from end-users.
To advance this effort, the U.S. Department of Energy recently launched a program to make green hydrogen commercially available at $1/kg by 2030 – cost-competitive with natural gas – although production methods have not been selected yet. Nuclear reactors could provide the large amounts of carbon-free electricity and high temperatures needed to establish a reliable, high volume green hydrogen supply chain.
Nuclear Hydrogen Production – EPRI’s Research
As part of the Energy Policy Act of 2005, the Department of Energy launched a public-private partnership called the Next Generation Nuclear Plant project, which sought to demonstrate and deploy an HTGR plant specifically for the production of hydrogen by 2021.
EPRI helped support the NGNP project with HTGR technological assessments and market analyses. Hydrogen economies work best at scale, and our research found that there could be a massive need for hundreds of HTGRs if a hydrogen economy were fully pursued.
However, hydrogen became much less economically competitive after natural gas prices crashed in 2008. Ultimately, the NGNP project folded in 2013.
Nonetheless, there is still significant interest in using nuclear energy for hydrogen production as a valuable revenue stream and carbon-free energy carrier, particularly with HTGR technologies now closer to market.
The success of nuclear hydrogen will depend greatly on how much market penetration hydrogen achieves. The greater the size of a hydrogen economy, the more likely that nuclear plants will contribute.
To learn more about opportunities for hydrogen production with nuclear energy, we recommend report 3002020437.
Heat Production
Nuclear reactors produce large amounts of heat, which could make them well suited to supply clean energy for commercial, residential, and industrial applications.
Nuclear Heat for Industry
Certain industrial processes require very high temperatures, such as purifying, synthesizing, and refining glass, cement, metals, ammonia, plastics, and petroleum products. Using nuclear power as a heat source could offset a significant amount of emissions from these processes.
To cogenerate electricity with heat for industry, it would be particularly advantageous to site a nuclear plant close to industrial centers. For several advanced reactor designs, the emergency planning zone will be within the nuclear plant’s site boundary, which would significantly reduce required area and improve site flexibility to be located closer to end users for enhanced reliability and economic benefits.
EPRI is exploring several possibilities for how nuclear plants could be co-located with shipyards and industrial parks to provide electricity, heating, liquid fuels, or a combination. Our results are freely available in report 3002018348.
Data centers consume 1% of the world’s electricity and like industrial parks, they could be served by nearby advanced reactors for a steady, reliable stream of electricity.
Nuclear District and Residential Heating
District heating networks centralize production of heating for several buildings, such as at universities, hospitals, military bases, and urban districts.
Nearly 90% of the world’s district heat is produced by fossil fuels, representing a large opportunity for decarbonization. Nuclear reactors could support heating, cooling, electricity, or a combination with a resilient, economic, scalable, and carbon-free model.
For example, the Haiyang Nuclear Energy Heating Project in Haiyang, China, provides heat for all of the city’s 670,000 inhabitants, offsetting 23.2 kT of coal and 60 kTCO2 per year.
Megawatt-scale microreactors may be well suited for this application because of their compact land footprint, inherent safety, and ease of installation and maintenance.
EPRI is leading the Nuclear in District Energy Applications Initiative (NuIDEA) to coordinate research, share knowledge, and address the remaining challenges in deploying microreactors for carbon-free district energy systems.
NuIDEA’s objectives and research roadmap are freely available in report 3002026195.
Nuclear Energy for Desalination
More than 2.2 billion people lack access to clean water, and this number is expected to grow in the coming decades. Desalination is a process that can be used to purify drinking water, typically from seawater, using heat and electricity.
Nuclear reactors could provide heat and electricity for desalination to offset emissions from other energy sources, and desalination technologies could be integrated into nuclear plant designs to operate even more efficiently.
There are countless examples of nuclear desalination plants all over the world today. Recently, the United Arab Emirates has completed three nuclear reactors and is constructing a fourth. Desalination is a main objective of these plants, helping to provide fresh water throughout the country.
Advanced nuclear reactors, particularly small modular reactors, could further be designed specifically for integrated desalination applications.
Desalination applications are highly location-dependent, so improved deployability and size variation of advanced reactor designs could allow them to be used in a wider range of scenarios to decarbonize and provide more clean water worldwide.
We elaborate on desalination applications of nuclear energy in 3002020437.
Energy Storage & Flexibility
At times when electricity sales are not profitable for nuclear plants, energy storage could be a viable application to improve sale arbitrage, allowing owner-operators to wait to sell energy at a more favorable time.
There are many ways to store energy; in all cases, a nuclear plant could divert its electric or heat output to another product. For example, the plant could charge batteries, generate liquid fuels such as hydrogen, generate heat for industrial or residential processes, fill pumped-hydro reservoirs, or even desalinate water for later consumption.
Storing energy in other forms could help cut losses during unprofitable market conditions without having to change the reactor’s output. To dive into the nuances of flexible applications of traditional nuclear plants, we recommend report 3002020436.
Flexible Electricity Production with Nuclear Energy
While flexible electricity production is not an application of nuclear beyond electricity per se, it is still a case worth examining because it represents a major shift in the role of today’s nuclear industry away from baseload electricity production.
Introducing load-following capabilities and flexible output could make the nuclear industry significantly more competitive in the electricity marketplace.
In France, nuclear plants have been designed to operate flexibly since the 1970s and 80s. During periods of low demand, operators can decrease reactor power to as low as 20% in 30 minutes so that no excess electricity is produced or wasted.
In the U.S., regulations require that changes in reactor power output must be performed by a licensed reactor operator. Even though it would be technically possible for a traditional nuclear plant to decrease its power output during a period of low demand or competitive pricing to cut losses, this is rarely done.
It is important to note that ramping power output of nuclear plants can put additional strain on their components, such as fuel cladding. Many U.S. owner-operators continue operating at full power even when electricity prices are negative to avoid potential maintenance costs from ramping.
However, the French nuclear utility EDF has mentioned that flexible operations have not significantly increased maintenance costs, largely because the reactors were specifically designed for flexible operations. In some cases, baseload nuclear plants in the U.S. could be retrofitted to improve their flexibility.
Many advanced reactor designs further include flexibility and ramping as key attributes to enhance economic competitiveness in future energy markets.
Flexibly operating nuclear reactors is a significant shift in the industry and could greatly enhance nuclear’s economics. We elaborate on some of the nuances in 3002020437.
Research Priorities for Nuclear Beyond Electricity
EPRI leads and conducts research efforts to help the nuclear industry achieve the decarbonization and economic benefits of applications beyond electricity. Our freely available report Nuclear Beyond Electricity-Landscape of Opportunities: Initial Survey and Near-Term Actions provides an overview of the projects that will help the nuclear industry succeed.
Our 2023 roadmap for the nuclear industry also notes three main challenges remaining for nuclear beyond electricity applications:
- Particularly for advanced reactors, these applications still need to be demonstrated.
- Applications beyond electricity will require fundamentally new business models for the industry.
- New regulatory frameworks will need to be developed for combined facilities with radiological and other hazards, such as industrial hazards.
With these in mind, we outline research objectives and priorities that will help nuclear beyond electricity applications succeed in the coming years. Learn more about the future of nuclear energy beyond electricity in the freely available roadmap.