Thought leaders on capacity factors and nuclear power

July 21, 2020, 7:13AMNuclear NewsSherry Bernhoft, Joel Eves, Margaret Harding, Jessica Lovering, Peter Lyons, Lisa Marshall, Craig Piercy, Edward (Ted) Quinn, Kelly Rae, Randy T. Simmons, Samuel Thernstrom, Doug True, Dan Yurman

This article first appeared in the May 2020 issue of Nuclear News.

Nuclear News reached out to leaders in the nuclear community to ask them for their views on the capacity benefits that come from nuclear. We received wide-ranging responses, from how capacity factors provide examples of the excellence of nuclear professionals, to the work being done at universities to continually improve capacity factors, to the importance of adding the word “inherent” to the conversation because forms of energy are different from one another and so inherent capacity factor is a critical piece of understanding.

If you have your own thoughts about capacity factor, please let Nuclear News know. If we collect enough comments, it may result in a Part 2 of this article in the future.

Desired attributes for new generations of nuclear power

Peter Lyons (left), ANS Board of Directors, former NRC Commissioner and DOE Assistant Secretary of Energy, and Edward (Ted) Quinn, President, Technology Resource, ANS Past President 1998-1999

In addressing the issue of diversity and reliability of supply of U.S. electricity in the future, we need to include consideration of replacement of existing nuclear plants, even after any second license renewals that are granted, with new advanced nuclear plants. This supports the criterion of maintaining an 18- to 24-month fuel supply on site, which has been a challenge issued by the Department of Energy to the Federal Energy Regulatory Commission. It also supports the goals of maintaining and expanding carbon-free generation. At a conference in March 2019, former Secretary of Energy Rick Perry said, “I don’t know how anybody who cares about the climate can’t be for nuclear energy.” The high capacity factors for nuclear plants, averaging over 92 percent across the country in 2018, provide superb reliability and give confidence to consumers and new-build consortia that our experience base can be extended with the addition of new nuclear plants.

So what new nuclear designs should move forward to commercialization in the United States and around the world? There has been a significant case made for, and investment in, new small modular reactor designs that can be built on an assembly line in a factory setting and cost a lot less than large-scale plants, like the AP1000. These SMRs could bring online electrical generation with less risk to the utility owner and development companies. This reduction in risk and higher probability of construction success is added to the benefits inherent in a number of these designs, including higher safety margins and the ability to load follow. Designs such as the one by NuScale Power (60-MWe module size with multiple modules per plant) have been supported by the DOE in the design and commercialization through Nuclear Regulatory Commission licensing that will complete this year. A first deployment at the Idaho National Laboratory by the Utah Associated Municipal Power Systems utility is planned with completion of construction by 2026.

(After intense cost evaluations, NuScale is now publicly forecasting a $65/MWh levelized cost of electricity for the first plant and construction costs for Nth-of-a-kind plants at $3,600/kW. This is far superior to the current AP1000 costs of the Vogtle project in Georgia.)

A number of other designs are also moving forward with DOE support and are expected to also be deployed and add to the U.S. energy mix in the coming years. The role of innovation in design has focused on enhanced safety while reducing both overnight construction costs and operation and maintenance (O&M) costs over the 40 to 60 years of the plant life, plus enabling higher operational temperatures for great efficiency and applicability. Also, significant advancements in the automation of work tasks have been made, which can reduce the size of the plant staff, including security, to a number more comparable with other types of electricity generation. This reduction in O&M is critical to the long-term competitiveness of nuclear versus other forms of generation, including natural gas.

To reduce the total costs of new nuclear generation, reductions are needed in each of the following areas:

total capital costs

financing needs, through reduced construction times

manufacturing costs

transportation costs

construction costs

operating costs

maintenance costs

security costs.

The newer designs coming forward are simpler and address the application of innovations to improve economics in each of these categories, paving the way for the long-term success of not just one, but multiple deployments of the same design—similar to how France and South Korea built their nuclear fleets in evolutions of advanced designs. We need to do the same in the United States and utilize our incredible wealth in talented young people to move the nation forward and return the United States to a global leadership position in nuclear.

The importance of the commercial nuclear energy industry was also recently noted in a report from the Energy Futures Initiative, whose president and CEO is former Secretary of Energy Ernie Moniz. That report, “The U.S. Nuclear Energy Enterprise: A Key National Security Enabler,” noted that “Nuclear power and a robust associated supply chain (equipment, services, people) are intimately connected with U.S. leadership in global nuclear nonproliferation policy and norms and with the nation’s nuclear security capabilities.”

The new microreactor concepts also deserve mention along with kudos for the Department of Defense for taking a leading role in financing these reactors, which are probably best suited to the military in their initial applications. Microreactors address a particular defense need and thus are not subject to the same stringent cost criteria that are essential for commercial competition; instead they must satisfy criteria established by the DOD. Recent announcements from the DOD of funded projects are a welcome addition of resources into new reactor concept research.

In many respects, the future of our planet depends on our ability to utilize non-carbon-emitting sources for the electricity and other energy sectors, and a major element of that is the economically prudent deployment of advanced nuclear energy plants in the United States and around the world.

Capacity Factors: Yet another example of nuclear professional excellence

Craig Piercy, Executive Director/CEO, American Nuclear Society

In 2019, the capacity factor of U.S. nuclear plants hit an all-time high of 93.5 percent. Honestly, it is a truly amazing feat that often gets lost in our public dialogue about energy use, cost, and market structure. No other form of electricity generation even comes close. Coal and natural gas plants consistently hover around 50-60 percent, while renewable generation like wind and solar is stuck in the 25-35 percent range.

Nuclear’s high-water mark in 2019 is not an outlier, either. The U.S. fleet has consistently operated more than 90 percent of the time on an annualized basis since 2014.

Ultimately, the capacity factors of our nuclear plants are a testament to the skill and dedication of the men and women who operate and maintain them. Like a Formula One pit stop for a race car, scheduled maintenance outages for nuclear power plants have become well-orchestrated ballets, choreographed in 15-minute increments. As a result, operators have cut the average refueling outage in half, from 66 days in 1995 to 32 days in 2019.

In these uncertain times, I find great comfort in the fact that we have a skilled cadre of professionals who consistently manage a complex technological challenge with such grace and aplomb.

Nuclear Beyond Electricity initiative: Looking toward the future of nuclear power generation

Sherry Bernhoft, Senior Program Manager, Nuclear Innovation Department, Electric Power Research Institute

Nuclear power plants are an important source of synchronous, low-carbon generation, but today they are operating in a challenging market environment due to increased variable generation, changing consumer behaviors, low electricity growth, and, in the United States, low natural gas prices. The Electric Power Research Institute (EPRI) has been working with a number of nuclear plant operators to successfully transition from baseload to flexible operations where the electrical output is varied on a seasonal, weekly, or daily basis in response to grid demand. Flexible operation supports grid integration with renewables and has helped a number of utilities manage periods of negative electricity prices and grid congestion.

Looking ahead at the continued importance of nuclear power on the grid for a low-carbon-energy future, EPRI has started a Nuclear Beyond Electricity initiative. Working with various stakeholders, including utilities, research institutions, and laboratories, among others, the initiative is exploring the economic, technical, and market aspects for both existing and new plants to provide valuable products and sources of revenue in addition to electrical generation. Some examples are isotope production, ancillary services such as frequency control and ramping services, and use of the surplus electrical or thermal energy for poly-generation. Some of the options for poly-generation are energy storage, industrial process steam, water desalinization, and production of alternate, no-carbon energy carriers such as hydrogen or ammonia.

Universities continue crucial work contributing to present, future capacity factors

Lisa Marshall, Director of Outreach, Retention & Engagement, North Carolina State University

According to the Energy Information Administration (EIA), the capacity factor for nuclear energy was 93.5 percent for 2019 and was rated at 101.7 percent in January 2020. Nuclear consistently produces operationally carbon-free, reliable power. Simply put, nuclear energy is a big part of the nation’s infrastructure allowing our communities to thrive—be it in normal or stressful times. We need not worry about powering our homes, which have also become offices for many during the coronavirus pandemic. Hospitals, fire stations, grocery stores, distribution centers, and data centers—all are utilizing nuclear energy so that health care providers, researchers, and others can concentrate on the tasks at hand.

North Carolina State University and colleges nationwide have moved classes online to finish the semester and continue the crucial task of preparing the next generation of students to contribute to current production and advanced reactor designs. Students are completing their senior design projects on such topics as molten salt reactor design, core optimization comparisons, and reactor modeling. We continue our partnerships with industry and national laboratories on these and other undergraduate and graduate research topics. Nuclear energy is an essential partner in innovation for a better tomorrow.

Nuclear load following for grid stability and resource diversity

Kelly Rae, Director of Public Relations, Energy Northwest

Energy Northwest’s Columbia Generating Station operates at 100 percent power, 24 hours a day, 7 days a week, but has the ability to load follow—or reduce power—when requested by the region’s Bonneville Power Administration (BPA) for grid stability, for hydroelectric system management, during periods of high wind, or for economic considerations.

Columbia is a boiling water reactor design and has utilized flexible power operations since installing an adjustable-speed drive system in the mid-1990s, which allows operators to adjust power by changing the amount of recirculation flow through the core. Reactor power can also be adjusted by changing the control rod pattern. For flexible power operations, Columbia uses set power levels depending upon the need. The station can generally reduce reactor power to 85 percent via flow rate reduction alone without moving any control rods.

However, during hot and cold months, when the wind typically doesn’t blow and electricity demands are high, BPA may request a “no-touch” order for Columbia because of the increased demand or limited availability of other energy resources. A no-touch condition restricts work activity that poses risk to generation or could result in a plant shutdown.

Can small-scale nuclear reactors scale up?

Jessica Lovering, doctoral student, Carnegie Mellon University Energy Growth Hub

When Oklo submitted the first non–light water reactor combined license application to the Nuclear Regulatory Commission, microreactors hit the main stage. Oklo’s 1.5-MW heat pipe reactor is targeting off-grid markets, but such a small design left many in the energy and climate communities wondering whether such reactors could really contribute to a large-scale energy transition. While we may never have microreactors rolling off assembly lines at the scale of wind turbines and solar panels, the commercialization of tiny, factory-produced reactors may still accelerate nuclear innovation and deployment in several ways.

Oklo piloted a new, streamlined licensing process that will hopefully be faster, more efficient, and cheaper to complete—taking as little as 24 months. Whether for a microreactor or a scaled-down version of a larger design, this streamlined process could allow for more iterative innovation and rapid demonstration. Even if microreactors don’t come to dominate the nuclear sector, their accelerated licensing and deployment could demonstrate a suite of novel concepts from fuel to operations, leading to faster adoption of cost-saving innovations across the industry. More importantly, microreactors are aiming for a new market not currently served by nuclear power and difficult to decarbonize, and they could well open even more sectors like direct industrial use, hydrogen production, and desalination—decarbonizing beyond the power sector.

The importance of inherent capacity factors

Margaret Harding, President, 4 Factor Consulting

I would add another word to talk about capacity factor: inherent capacity factor. Why the capacity factor of one form of energy is different from another is a critical piece of understanding.

Nuclear plants have very high capacity factors because nuclear doesn’t load follow well and because costs are largely fixed whether the plant runs or not. Nuclear was also some of the lowest-cost energy on the grid for many years.

Many natural gas plants operate at relatively low capacity factors because they are better designed for responding to peak load requirements and because their underlying costs are largely tied to the fuel used. Natural gas was some of the highest-cost energy on the grid until the fuel prices dropped so low. Natural gas can operate at high capacity factors. The inherent capacity factor of natural gas can be quite high.

Renewables like wind and solar run at low capacity factors because of the inherent nature of the generated electricity. Solar, for example, cannot operate at capacity factors in excess of 40 percent (and they are usually much lower) because the sun isn’t shining at night and is at low angles for much of the day. Similar statements can be made of wind. The inherent capacity factors of renewables are much lower than those of natural gas or nuclear.

Failure to properly evaluate and understand the inherent capacity factor results in an inaccurate assessment of various energy sources. When people talk about installed capacity factor, one should always ask, What is the inherent capacity factor of the facility?

High capacity factors—and capital utilization rates—are key to affordable decarbonization

Samuel Thernstrom, Executive Director, Energy Innovation Reform Project

The challenge of decarbonizing energy systems—beginning with electricity generation—while preserving their affordability and reliability is increasingly important. System design is crucial to this transition. Uncoordinated, incrementally cost-effective steps won’t produce an efficient system; instead, the result will be akin to the New York City subway map, an incoherent network produced by competing short-term interests.

Many scholars have emphasized the value of high capacity factors. Intermittent generation can be cost-competitive in many markets when it is available, but as market penetration increases, it places greater demands on dispatchable generators to provide large amounts of power when sun and wind are unavailable.

The underappreciated corollary to the crucial significance of capacity factors is the importance of capital utilization rates. Given the multibillion-dollar cost of baseload-serving electric power plants, it is only economical to maintain a generating unit if it can sell power for most hours it is capable of operating. If baseload clean generation sources such as nuclear are made to follow and fill in for intermittent generators, the utilization rates of all capital—both nuclear and renewables—will fall as we approach decarbonization, undermining the affordability of the system.

Decarbonization pathways that reflect the value of high capacity factors and capital utilization rates are crucial to preserving the affordability and reliability of electric power generation.

New revenue model based on heat as the product

Dan Yurman, Publisher, NeutronBytes blog

A revenue model that holds promise for developers of small modular reactors based on Generation IV designs is to offer heat as the primary output of their plants.

Heat can be used to generate electricity, but it can also be used for process heat for industry, especially for manufacturing steel, cement, and chemicals; the production of hydrogen; and desalinization. The combination of revenues from these heat streams could expand the business case for advanced reactors as a result. Investors would then be able to look beyond the levelized cost of electricity when evaluating the business prospects for a new reactor design. Of course, grid services to support solar and wind energy projects would also still be available.

With a growing realization that nuclear energy is necessary to achieve decarbonization in the electric generation utility industry, and in major process heat applications, the 2020s looks like a decade where action based on this concept could see more significant developments for nuclear energy worldwide.

The combination of revenues from these heat streams could expand the business case for advanced reactors as a result.

Lehi, Utah: Increasing flexible capacity in a growing community

Joel Eves, Power Department Director, City of Lehi, Utah

In Lehi, Utah—south of Salt Lake City—there are several reasons why our roughly 22,000 customers could benefit from electricity made from small modular nuclear reactors.

First, our city is growing by between 1,000 and 1,500 customers per year. As that population increases, so does our load growth. Second, as a member of the Utah Associated Municipal Power Systems (UAMPS), we anticipate the loss of two coal-fired power plants by 2023, after which only 1.7 MW of coal will remain to help handle a peak load of 120 MW. Third, we must have flexible capacity to handle variable loads and unpredictable wind and solar power. As we see more variable loads coming online, we need resources that will respond quickly.

Part of the solution is a new internal natural gas power plant, but that leaves our customers vulnerable to price fluctuations. The UAMPS Carbon Free Power Project—a 720-MW SMR power plant planned for Idaho National Laboratory—will provide us with a flexible, reliable source of power and a buffer against variable fuel prices.

The great untold story

Doug True, Chief Nuclear Officer and Senior Vice President of Generation and Suppliers, Nuclear Energy Institute

The great untold story of the U.S. energy sector is that our nuclear reactors produced more power in 2019 than ever before.

Thanks to a stunning 93.5 percent average capacity factor, the 98 reactors operating in 2019 produced 809.4 million MWh of electricity, a record high. That is more carbon-free electricity than all other carbon-free sources combined.

Through its Delivering the Nuclear Promise initiative, the industry committed to reducing costs by 30 percent from 2012 peak levels. Last year, the industry exceeded this goal, reducing the costs by 32 percent, while consistently maintaining high safety standards.

To put it in perspective:

Efficiency improvements and power uprates generated additional electricity equivalent to 32 new reactors compared to what was produced 30 years ago, when the capacity factor was much lower.

This high capacity factor is why nuclear energy complements other carbon-free technologies. Per the U.S. Energy Information Administration, the 2019 capacity factors for wind, utility-scale solar, and hydro were 34.8 percent, 24.5 percent, and 39.1 percent, respectively.

Average generating costs for the U.S. nuclear fleet, at $30.42/MWh, are the lowest since industry-wide data collection started in 2002. Another record!

These achievements are a testament to the hard-working women and men in the nuclear industry.

The footprint of energy

Randy T. Simmons, President, Strata Policy

Electricity generation is energy intensive, and each source leaves its own environmental and ecological footprint. We considered the various direct and indirect land requirements for coal, natural gas, nuclear, hydro, wind, and solar electricity generation in the United States in 2015. The land used by each source was approximated to account for that used during resource production, for energy plants, for transport and transmission, and for storing waste materials. The final assessment can be seen in the accompanying chart, which shows how many acres per megawatt each source of electricity uses.

Coal, natural gas, and nuclear power all feature the smallest, and nearly identical, physical footprint—about 12 acres per megawatt produced. Solar and wind are much more land-intensive technologies using 43.5 and 70.6 acres per megawatt, respectively. Hydroelectricity generated by large dams has a significantly larger footprint than any other generation technology using 315.2 acres per megawatt.

By understanding the physical footprint impacted by electricity production, effective policy action can be taken to balance environmental impact, reliability, economy, and security. If minimizing overall land use in generating electricity is a priority, land-efficient sources like nuclear power should be considered while land-intensive sources should be weighed against competing priorities.