Definitions

Definitions of common terms in the 2025 Electricity Annual Technology Baseline (ATB) are presented below for the following:

• Parameters
• Other Data Dimensions
• References.

Parameters

The following cost items are included in capital expenditures (CAPEX) for all technologies, unless otherwise noted. Individual technologies may include additional items as explained on the technology pages.

Inclusions in CAPEX

Specific components of CAPEX are defined as follows:

Capital expenditures excluding construction period financing and grid connection costs. Overnight capital cost (OCC) includes on-site electrical equipment (e.g., switchyard).

The ATB assumes grid connection cost (GCC) of $104/kilowatt (kW), in 2023 USD, for utility-scale technologies. The default GCC includes typical costs for a spur line (short, radial transmission lines from generator to the bulk grid), point of interconnection, and nominal network upgrades. This is equal to the sum of the typical estimated costs to connect a new natural gas plant in most market regions in the United States reported in (Seel et al., 2023) (for completed and active projects), plus a 1-mile spur line (Ramasamy et al., 2022), with the dollar year adjusted for inflation. These values are typical for a plant located near a load center. These costs have significant regional and site-specific variation, including within resource classes. These variations for wind and solar projects are modeled within the Renewable Energy Potential (reV) and Regional Energy Deployment System (ReEDS) tools and are used to inform the National Laboratory of the Rockies's Standard Scenarios. ReEDS also includes a distance-based interconnection cost for pumped storage hydropower. The assumed GCC value in the 2025 ATB does not vary by resource class for all technologies except offshore wind. The ATB focuses on core technology improvements and does not incorporate these site-specific considerations for GCC.

Offshore wind includes additional distance-based costs of spur lines over land, offshore wind plant export cable costs, and construction period transit costs.

Also referred to as construction finance cost, this is a portion of all-in capital cost associated with construction period financing. This is a function of construction duration, capital fraction during construction, and interest during construction.

The following operating expenditures are included in operations and maintenance (O&M) expenditures for all technologies, unless otherwise noted. Individual technologies may include additional items as explained on the individual technology pages. For nuclear energy, see the technology page for what is specifically included in fixed and variable costs.

Inclusions in O&M

Capacity factor is generally defined as the ratio of actual annual output to output at rated capacity for an entire year, using a long-term average over the lifetime of an asset, without curtailment for renewable generation. The default capacity factors listed in the ATB data spreadsheet are meant to be representative—actual plant capacity factors will depend on many factors and power-plant-specific conditions. The annual capacity factor ignores specific operating behaviors such as ramping, startup, and shutdown that could be relevant for more detailed evaluations of generator cost and value. Electricity generation technologies have various capabilities to provide capacity and flexibility services. These services are difficult to value and depend heavily on the system in which a new generation plant is introduced. These services are represented in electric sector models such as ReEDS and in corresponding analysis results such as the Standard Scenarios.

Performance Metrics Inclusions

Key performance metrics such as capacity factor, heat rate, and carbon capture percentage can vary with real-world conditions. The table below captures these real-world phenomena included quantitatively, documented qualitatively, not included, or not applicable to each ATB metric. More information is available on the pages for each technology.

Effects Included in Performance Metrics

Levelized cost of energy (LCOE) is a summary metric that combines the primary technology cost and performance parameters: capital expenditures, operating expenditures, and capacity factor. It is useful for discussing technology advances that yield future projections because it illustrates the combined effect of the primary cost and performance parameters in each of the ATB technology innovation scenarios. The Electricity ATB focuses on defining the primary cost and performance parameters for use in electric sector modeling or other analysis where more sophisticated comparisons of technologies are made. LCOE accounts for the energy component of electric system planning and operation. It uses an assumed annual average capacity factor when spreading costs over the anticipated energy generation. 

Although LCOE accounts for many variables important to determining the competitiveness of building and operating a specific technology (e.g., upfront capital costs, capacity factor, and cost of financing), it does not necessarily demonstrate which technology in a given place and time would provide the lowest-cost option for the electric grid. Importantly, LCOE does not capture the economic value of a particular generation type to the system and therefore may not serve as an appropriate basis for comparing technologies. For example, LCOE ignores attributes that can vary significantly across different technologies—in terms of both capability and cost (e.g., ramping, startup, and shutdown)—that could be relevant for more detailed evaluations of generator cost and value to the system. Such analysis is performed using electric sector models such as ReEDS and corresponding analysis results such as the Standard Scenarios. The ATB calculates a before-tax LCOE, meaning the costs include both taxes and tax benefits. For more details, see the LCOE equations or (Short et al., 1995).

The 2025 ATB does not include calculation of LCOE or other related financial parameters for fossil-fueled technologies. Refer to the techno-economic studies of electricity generating plants described in the U.S. Department of Energy's National Energy Technology Laborotory's Quality Guidelines for Energy Systems Studies documents (Theis, 2021) for analytic metrics it recommends as more appropriate to fossil energy technologies, applications, and industries.

Other Data Dimensions

Year

2023 is the Base Year for the 2025 ATB because this is the year for which sufficient historical data are available. Sources for the Base Year include cost and performance estimates from published, regularly updated sources or methods. If estimates are not based directly on market data, they are compared with market observations as possible.

2023–2060 is the range of 2025 ATB projections. Projections are based on trend lines between historical data and long-term (2030 or 2035 and 2050) estimated costs. For most technologies, the Base Year (2023) is the final year of historical data; see below for an explanation of 2023 costs. Near-term values in the ATB do not reflect every local or near-term market condition. The long-term ATB projections are not informed by recent changes.

All monetary values are in 2023 USD based on the Consumer Price Index for All Urban Consumers (BLS, 2025a) for dollar year conversions, where the publication source year dollars do not match 2023 unless noted otherwise. Prices are not rigorously distinguished from costs. 

Financial Assumptions Cases

Financial assumptions impact LCOE by changing the cost of capital needed to finance electricity generation projects. Two project finance structures are used within the ATB: a Without Tax Credits case (analogous to the Research and Development [R&D] Only case in previous Electricity ATBs) and a With Tax Credits Assumptions case (analogous to the Market + Policies case in previous Electricity ATBs).

This sensitivity case allows technology-specific changes to debt interest rates, return on equity rates, and debt fraction to reflect the effects of R&D on technological risk perception, but it holds background rates constant and excludes the effects of tax reform and tax credits. See financial assumptions cases and methods for details. 

This sensitivity case retains the technology-specific changes to debt interest and return on equity rates from the R&D Only case and incorporates the effects of the tax credits in the Inflation Reduction Act of 2022. See financial assumptions cases and methods for details.

Estimates costs based on R&D-driven improvements only, as applied to technologies and conditions existing during the most recent year with historical data (R&D in charts). The R&D Only Cost Drivers Case is the core technology cost case and is analogous to previous editions of the ATB. 

Estimates costs based on R&D-driven improvements plus other cost drivers, such as changing market and supply chain conditions (Exp in charts).

The expanded cost drivers cases is presented as a limited pilot in the 2025 ATB and is included for PV, Land-Based and Distributed Wind, and Battery technologies.

Technology Innovation Scenarios

The three technology innovation scenarios for the R&D cases are generally described as follows:

Historical investments come to market with continued industrial learning. Technology looks similar to today, with few changes from technology innovation. Public and private R&D investment decreases.

Innovations observed in today's market become more widespread, and innovations nearly market-ready today come into the market. Current levels of public and private R&D investment continue. This scenario may be considered the expected level of technology innovation.

Innovations far from market-ready today are successful and become widespread in the market. New technology architectures could look different from those observed today. Public and private R&D investment increases.

The Expanded Cost Drivers case has additional components to the scenarios. These scenarios typically include the R&D cost trajectories defined by the above scenarios in addition to other factors.

Reflects a trajectory at the high end (but not necessarily upper bound) of technology costs in future scenarios, driven by increased commodity prices, supply chain challenges, and unfavorable financial terms.

Reflects a future trajectory toward middle-ground commodity cost, supply chain, and financial conditions.

Reflects a reasonable lower bound of costs across a variety of market factors, including smoothly operating and scaled supply chains and favorable financial terms.

For nuclear and biopower technologies, technology cost designations appearing in ATB tables and figures refer to technology assumptions and the range of fuel price projections as described on their respective technology pages.

Technologies that present an expanded cost drivers financial case may use different definitions for the scenarios in that case. See specific technology pages for the details of the scenario inclusions or exclusions as well as factors that expand the costs relative to R&D only cost drivers.

Types of Evidence

Each core metric (not calculated metrics) within the Electricity ATB is assigned a type of evidence based on what references were used to inform that data point. Types of evidence may vary throughout the timeseries for each metric or may vary by scenario. Definitions of the types of evidence are as follows:

• Empirical Market Data: Observed data from installed plants.
• Bottom-up analysis: Validated: Data derived from a model that sources inputs from industry or current literature; outputs have been compared to operating plants.
• Bottom-up analysis: Modeled: Data derived from a model of a hypothetical plant in the Base Year.
• Bottom-up analysis: Future: Data derived from a model of a hypothetical future plant.
• Calculated: Single Metric Learning Curve: A projected point based on a learning rate and potential future deployment applied to a single ATB metric (such as OCC, O&M, or LCOE).
• Calculated: Component-Level Learning Curve: A projected point based on a learning rate and potential future deployment applied to subcomponents (such as balance of system or labor within OCC), which are combined into ATB metrics.
• Calculated: Interpolation: A projected point that is a fit between two bottom-up analysis points.
• Calculated: Extrapolation: A projected point that goes beyond techno-economic analysis (TEA) or the literature and is extrapolated from previous trends. Use these points only with appropriate caution and evaluation of their uncertainty.
• Literature Fit: A point chosen from the literature by a percentile or other means that does not match one of the above.
• Expert Elicitation: Data derived from a combination of expert judgments.
• Multiple References - See Documentation: Data derived from multiple sources and/or that may vary by technology detail. See documentation for more details.
• N/A: This metric by definition does not apply to the selected technology.

Cost Recovery Period

An important assumption for computing LCOE is the assumption about the period over which the electricity generation plant's cost and performance is levelized. In the ATB, this period is defined as the cost recovery period, and it represents the period over which the initial capital investment to build a plant is recovered. Three options are available for the cost recovery period. Use the chart below to explore the effects of the cost recovery period.

The technical life for each technology is shown in the following table. A technical life longer than the cost recovery period means residual value may be left after costs have been recovered. The value of a 30-year life is justified by current industry trends, such as for wind technologies. However, ReEDS continues to use a 20-year cost recovery period for all generating technologies regardless of their technical life.

Technical Lifetimes for Technologies

Technology Detail Assumptions

Technology details indicate resource levels and specific technology subcategories. Minima and maxima show the range of resource- and technology-specific values. For renewable technologies, ranges span resource characteristics available within the contiguous United States.

The ATB plant characteristics (and associated resource quality) that most closely align with recently installed or anticipated near-term installations of electricity generation plants are defined as the representative value. The representative value for renewable technologies is calculated based on the resource quality used in recent or near-future plants in the Base Year, in combination with the technology cost and performance and financial assumptions indicated. For coal and natural gas technologies, only technology cost and performance are indicated. The technology detail plant characteristics selected as representative values are as follows (see individual technology pages for descriptions of ATB representative plant characteristics):

• Land-Based Wind: Wind Speed Class 4 - Technology 1
• Offshore Wind: Wind Speed Class 3
• Distributed Wind: Wind Speed Class 7
• Utility-Scale PV: Class 5: global horizontal irradiance (GHI) of 4.75–5 kilowatt-hours per square meter per day (kWh/m²/day)
• Commercial PV: Class 5: GHI of 4.75–5 kWh/m²/day
• Residential PV: Class 5: GHI of 4.75–5 kWh/m²/day
• Concentrating Solar Power: Class 2: excellent resource (refers to Daggett, California resource of 7.65 kWh/m²/day direct normal irradiance [DNI])
• Geothermal: hydrothermal flash technology
• Hydropower: nonpowered dam (NPD) 1
• Utility-Scale PV-Plus-Battery: Class 5: GHI of 4.75–5 kWh/m²/day
• Utility-Scale Battery Storage: 60 megawatts (MW); 240 megawatt-hours (MWh)
• Commercial Battery Storage: 1,800 kW; 7,200 kWh
• Residential Battery Storage: 5 kW; 12.5 kWh
• Pumped Storage Hydropower: National Class 3: 1,063-MW average generation capacity for closed-loop sites
• Fossil Energy Technologies:
  • New natural gas: natural gas combined-cycle (NGCC; F- or H-frame, depending on generation sizing needs): 95% carbon capture and storage (CCS)
  • New coal: Coal: 95% CCS
• Nuclear:
  • Large reactor: 1,000 MW
  • Small modular reactor (SMR): 300 MW
  • Microreactor: 6.2 MW
• Other technologies (EIA):
  • Biopower: U.S. Energy Information Administration (EIA)-dedicated.

Technology details can be classified as mature or nascent. Technology details are defined as mature if a representative plant is operating or under construction in the United States in the Base Year. In the data master spreadsheet, mature technology details are marked with "Y" in the maturity column, and nascent details are marked with "N." 

Standard Assumptions (unless otherwise noted on specific technology pages)

Labor costs are the average of union and nonunion labor rates.

Capital costs represent a national average benchmark. Regional variations are not applied.

Materials costs are given in 2023 USD, based on the Consumer Price Index for All Urban Consumers (BLS, 2025a) for dollar year conversions. 

Technology costs assume fully mature and industrialized supply chain and that manufacturing capacity for a given technology as well as economies of scale are reached.

Financial assumptions include financial effects of selected laws and regulatory regimes currently in effect.

All values are given in 2023 USD. Dollar year conversions for where the source year dollars do not match 2023 and done with technology specific indices including CPI (BLS, 2025a), PPI (BLS, 2025b), and the Chemical Engineering Plant Cost Index (Chemical Engineering, 2025). See the technology references table in the main data workbook for details.

Financial calculations for projections use an inflation assumption when converting between nominal and real interest rates. This value is assumed to be 2.5% in the R&D case, and the same value is used for 2025 through 2050 in the Markets + Policies case. Other years are reflected in the following table.

Although inflation may be higher or lower in any particular year, these values represent average inflation over the life of the project.

Other

Regional multipliers are not used in the ATB, but they are often applied in modeling tools such as ReEDS. For regional capital cost multipliers for the United States, see the ReEDS model documentation (Ho et al., 2021). 

This factor is applied to an OCC to represent the financing costs incurred during the construction period. In the calculation of construction finance factor in the ATB spreadsheet, Year Index 0 is closest to the plant's commercial operation date, and the highest year number corresponds to the start of construction.

Limitations

See the following links for the disclaimer agreement and a guide to technical limitations.

References

The following references are specific to this page; for all references in this ATB, see References.