Latest electricity cost estimates get new details on nuclear

July 1, 2024, 12:00PMNuclear News

Every year, the National Renewable Energy Laboratory (NREL) puts out a set of technology-specific cost and performance parameters for electricity generation. Now in its 10th year, the Electricity Annual Technology Baseline (ATB) has nearly 100,000 users from 144 countries, according to NREL. Utility planners and grid operators who look to the ATB to assess their investment options in a changing market require complete and accurate information and will be glad to know that the 2024 Electricity ATB, released June 24, includes—for the first time—a range of data on nuclear energy.

While previous ATBs included nuclear data based on single-point estimates from the U.S. Energy Information Administration’s Annual Energy Outlook, the 2024 version includes detailed cost information on two representative reactor sizes: large (1,000 MWe) and small (300 MWe) over a 20-year span from 2030 to 2050. The data is based on Meta-Analysis of Advanced Nuclear Reactor Cost Estimations, a report from Idaho National Laboratory’s Gateway for Accelerated Innovation in Nuclear (GAIN).

Parameters: The 2024 Electricity ATB includes both present costs and projections through 2050, with parameters including capital expenditures, operation and maintenance expenditures, capacity factors, and levelized cost of energy (LCOE). The ATB website provides in-depth documentation, including details on historical trends, current estimates, and future projections.

Two sets of financial assumptions are used: The Market and Policies case includes some production and investment credits from the Inflation Reduction Act; the R&D Only case does not. Market and Policies includes investment tax credits of 30 percent through 2050 for most clean energy technologies, including nuclear energy. Land-based wind and utility scale solar photovoltaics (PV) are notable exceptions. Production tax credits of $27.50/MWh are applied to a handful of technologies: land-based wind, utility-scale solar PV, biopower, and utility-scale PV plus battery.

The ATB charts three technology innovation scenarios for every energy technology—conservative, moderate, and advanced—that correspond to different levels of public and private research and development investment. Investment decreases in the conservative scenario, remains consistent in the moderate scenario, and increases in the advanced scenario.

“Technology-agnostic” nuclear: When it comes to nuclear power, the Electricity ATB (and the INL Meta-Analysis it is based on) includes cost estimates not for first-of-a-kind or nth-of-a-kind reactors but for "between first- and nth-of-a-kind" plants, dubbed “BOAK”. One large reactor design and one small reactor design are assumed, for the sake of cost evolution calculations, each to have captured 25 percent of the market for new nuclear power plants.

What reactor type or reactor vendor that might be the ATB and the Meta-Analysis does not presume to guess. The ATB data for large and small reactors are “technology-agnostic” and represent an “amalgamation” of pressurized water reactors, boiling water reactors, high-temperature gas reactors, sodium fast reactors, and molten-salt reactors. This approach was taken, according to the ATB website, because “1) all technologies are being actively pursued with near-term FOAK demonstrations announced, 2) it can be challenging to predict which technology will prevail and capture the 25 percent market share assumed here, and 3) uncertainty in cost estimates are too great to infer differences in costs between design types at this stage.”

The nuclear projections are based on a compilation of 35 detailed cost estimates for reactors, along with two datasets of historical U.S. costs for nuclear power plants. After the data was processed to ensure a valid cross comparison, quartiles were assigned to correspond with three different ATB scenarios. Q1 includes data points closest to “a well-executed next commercial offering” and corresponds to an advanced scenario that ensures cost overruns are avoided, while Q2 is the moderate and “most likely” scenario, and Q3 includes data points closest to FOAK cost ranges and is a conservative scenario “in which many of the challenges faced with the FOAK have not been resolved when the next unit is built.”

Large reactor construction times for the advanced, moderate, and conservative scenarios, respectively, are 60, 82, and 125 months, while those for small reactors are 43, 55, and 71 months. Cost evolution is driven by better project execution and experience gained from deploying standardized reactor designs. While the conservative scenario would see only 12 GW of nuclear power deployed by 2050, the moderate scenario would see 34 GW, and the advanced scenario 200 GW.

The projections include nuclear deployments in both the United States and Canada in learning rate calculations, “because some of the first technologies to be deployed in both countries are identical, which will result in learnings being directly applicable in the United States as well as linking supply chains across borders,” according to the ATB website.

Capacity and grid: Nuclear power stands out in the ATB for its consistent projected capacity factors of 93 percent. Capacity factors for solar and wind technologies are predicted to increase over time, based on “NREL internal modeling taking into account improvements in degradation and increases in energy yield.” Those projected capacity factor increases contribute to the anticipated decrease in LCOE for wind and solar.

Grid connection costs of a flat $100/kW are quoted for nuclear and several other technologies: land-based wind, utility-scale solar PV, concentrating solar power, geothermal, and utility-scale PV plus battery. Offshore wind has significantly higher grid connection costs, while other technologies (including distributed wind and solar) are assessed in the ATB with a grid connection cost of $0. However, given that grid operators have increasingly restricted wind generation from existing assets, citing both oversupply and grid congestion, the full cost of a reliable grid connection for new wind and solar capacity—especially for remote installations some distance from existing transmission lines—could be difficult to predict.

Countless factors: The sheer volume of data in the Electricity ATB makes it clear that NREL—and those making investments in the grid—has a difficult task in comparing electricity technologies that are less alike than apples and oranges.

In the case of wind and solar generation, the ATB includes a range of different technologies: different turbine diameters, in the case of land-based wind, as well as solar PV at both distributed and utility scales with and without batteries. Because solar and wind generation varies by season and geography, not to mention time of day, the ATB includes 10 different classes of resource characteristics for land-based wind and utility PV, which categorize regions of the nation by mean wind speed and solar radiation to estimate the capacity factor that could realistically be generated.

Looking specifically at land-based wind resource characteristics, wind speed Class 4 is “indicative of a moderate-quality wind regime and is intended to be a representative wind resource for most wind projects installed in the United States,” while Class 1 sites have the fastest mean wind speeds in the nation. The LCOE for Class 4 generation was $33/MWh in 2022 without tax credits. Add credits, and Class 4 LCOE was $18/MWh in 2022. Class 4 wind generation data is based on the mean wind speed range of the top 4–8 percent of all potential wind capacity in the contiguous United States. About half of the nation’s potential wind resources sit in the bottom three wind speed classes—8, 9, and 10—and may, to achieve the LCOE depicted in the ATB, require taller and broader wind turbines. The full range of LCOE for land-based wind in 2022 (with credits) was $14/MWh to $65/MWh.

Room for improvement: Given the range of wind, solar, and other renewable technologies and resource classes analyzed in the ATB, there is room for nuclear power details beyond large and small. Cost considerations for nuclear technologies paired with thermal energy storage or nuclear power deployed at a retiring coal generation site are discussed in INL’s Meta-Analysis but are not yet included in the ATB. As deployment of nuclear energy technologies move forward, actual costs will be incorporated to narrow the projected cost range.

NREL’s inclusion of information on nuclear power in the ATB is making progress. In 2023, nuclear generation was included in a LCOE range table, segregated at the bottom of the chart as a “conventional” technology. In 2024, the “conventional” label is gone, but nuclear energy is still relegated to the bottom of the table and is not listed in alphabetical order like the other technologies.

The ATB data applies shades of gray to tabs for nuclear, natural gas, and coal generation data, in contrast to the colorful tabs assigned to renewable technologies. Maybe nuclear energy could join the ranks of inherently low-carbon electricity technologies with a color of its own in 2025—a shade of green would be nice.

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