ATB data for concentrating solar power (CSP) are shown above. CSP costs in the 2020 ATB originated from (1) an NREL survey leading to updated cost estimates in the System Advisor Model (SAM Version 2017.09.05) and (2) further cost estimates for CSP components that have been in SAM from Version 2018.11.11 (Craig Turchi et al. 2019). The SAM 2018 costs translate to ATB costs in 2021 that are due to the three-year construction period. (SAM costs are based on the project announcement year, while the 2020 ATB is based on the plant commissioning year). Future year projections are informed by the published literature, NREL expertise, and technology pathway assessments for CAPEX and O&M cost reductions.
The three scenarios for technology innovation are:
Solar resource is prevalent throughout the United States, but the Southwest is particularly suited to concentrating solar power (CSP) plants. The direct normal irradiance (DNI) resource across the Southwest, which is some of the best in the world, ranges from 6.0 to more than 7.5 kWh/m2/day (Roberts 2018). The raw resource technical potential of seven states (Arizona, California, Colorado, Nevada, New Mexico, Utah, and Texas), considering regions in these states with an annual average resource > 6.0 kWh/m2/day, exceeds 11,000 GWe, or almost tenfold the current total U.S. electricity generation capacity (Mehos, Kabel, and Smithers 2009).
For illustration in the 2020 ATB, a range of capacity factors calculated in the NREL System Advisor Model (SAM Version 2018.11.11) is associated with three resource locations in the contiguous United States for three classes of insolation:
As noted, there are potentially over 11,000 GWe of viable electricity generation potential in the Southwest of the United States, all above 6.0 kWh/m2/day; thus, all the current generation potential is in the Class 1, Fair Resource class or better. A key finding of Murphy et al. is that if future costs of CSP decrease sufficiently, CSP could be deployed across a greater range of the United States and DNI resources (e.g., the South and Southeast); if this were to happen, the 2020 ATB resource classes would be expanded.
CSP research for today's and future advanced technologies is primarily in four main areas, the powerblock, the receiver, the thermal storage and the solar field. The table highlights key innovation and research trends for the Conservative, Moderate and Advanced Scenarios:
No change is expected if costs stay similar to present.
No change is expected if costs stay similar to present.
No change is expected if costs stay similar to present.
No change is expected if costs stay similar to present.
Technology Description:Supercritical cycle (supercritical carbon dioxide carbon dioxide [sCO2]) operates at 565°C with today's salts.
Justification: The DOE Supercritical Transformational Electric Power program and other countries are researching the use of sCO2 with today's salts e.g. China.
DOE and Zhipeng et al. (2019)
Technology Description:Advanced coatings are applied to today's receiver technology.
Justification: Testing of the coatings have founds increased selective absorption, and enhanced durability.
Technology Description:Tank designs, pumps, and component configurations are improved.
Justification: Engineering studies to improve designs are ongoing.
DOE report in progress
Technology Description:Heliostat installations improve, and learning occurs due to deployment
Justification: There is a significant pipeline of projects, and projects are currently being constructed. (Craig Turchi et al. 2019)
Elevated temperature sCO2 (>700°C) powerblock
High temperature receiver consistent with >700°C power cycle
Advanced storage compatible with >700°C delivery system
Low-cost, modular solar fields with increased solar field efficiency
Higher cycle efficiencies and potential reduction in powerblock CAPEX and OPEX
Higher temperatures delivered to thermal storage and powerblock
Lower cost storage medium and therefore, CAPEX reductions; the increased storage temperature, then feeds into the increased delivery temperature.
Significantly lower CAPEX and OPEX for future CSP plants; increased automation and reduced assembly times decrease construction times.
Mehos et al. (2017)
Moderate Scenario: Description
Supercritical cycle (sCO2) operating at 565°C with today's salts
Advanced coatings to be applied to today's receiver technology.
Improved tank designs and pumps, that include the relocation of the salt to steam heat exchanger.
Improvements in heliostat installations, leading to decreases cost due to increased deployment and learning.
Moderate Scenario: Justification
The DOE Supercritical Transformational Electric Power program and other countries are researching the use of sCO2 with today's salts e.g. China.
Testing of the coatings have founds increased selective absorption, and enhanced durability.
Engineering studies to improve designs are ongoing.
There is a significant pipeline of projects, and projects are currently being constructed.
DOE and Zhipeng et al.
DOE report in progress
Projections of future utility-scale CSP plant CAPEX and O&M are based on three technology innovation scenarios developed for scenario modeling as bounding levels. In general, differences among the technology innovation scenarios reflect different levels of adoption of innovations. Reductions in technology costs reflect the cost reduction opportunities that are listed below.
These improvements are reflected in the following tables.
In the 2020 ATB, concentrating solar power (CSP) technology is assumed to be molten-salt power towers. Thermal energy storage (TES) is accomplished by storing molten salt in a two-tank system that includes a hot-salt tank and a cold-salt tank. Stored hot salt can be dispatched to the power block as needed, regardless of solar conditions, to continue power generation and allow for electricity generation after sunset. CSP technology in the 2020 ATB is represented as 100-MWe molten-salt power towers, which use today's sodium and potassium nitrate salts, with 10 hours of TES using a two-tank molten salt system. This configuration is similar to the Crescent Dunes CSP plant in Nevada, is representative of new global CSP development, and has the potential for further cost reductions relative to other configurations, such as parabolic trough.
In 2019, parabolic trough projects made up approximately 1 GW of the CSP projects under construction, followed closely by power towers at 0.8 GW of plants under construction. Molten-salt power tower plants are being built in Chile (e.g. Cerro Dominador) and Dubai (NREL, "Concentrating Solar Power Projects"). The largest CSP plant being constructed in the world is the 700-MW combined parabolic trough and power tower system in Dubai, United Arab Emirates (UAE). This Dubai Electricity and Water Authority (DEWA) 700-MW complex is comprised of 600 MW of parabolic troughs (i.e., 3 x 200-MW trough plants) and a 100-MW power tower site, with each plant having 12–15 hours of TES (SolarPACES 2019; Lilliestam and Pitz-Paal 2018).
Most new global capacity of CSP plants in development is from molten-salt power towers; for example, 3.7 GWe of molten-salt power towers and 1.3 GWe of parabolic are in development (IRENA 2018). Current indications are that molten-salt power towers have the greatest cost reduction potential, in terms of both CAPEX and LCOE ((IRENA 2016), (Mehos et al. 2017)). These are part of the DOE Generation 3 (Gen3) road map for the next generation of commercial CSP plants (Mehos et al. 2017).
Crescent Dunes (110 MWe with 10 hours of storage) was the first large molten-salt power tower plant in the United States. It was commissioned in 2015 with a reported installed CAPEX of $8.96/WAC ((Danko 2015), (Taylor 2016)). Despite the emergence of power tower systems, the CSP landscape is still dominated by parabolic trough systems. The United States is home to:
The CSP technologies highlighted in the 2020 ATB are assumed to be power towers but with different power cycles and operating conditions as time passes, as shown in the following table:
A molten-salt (sodium nitrate/potassium nitrate; aka, solar salt) power tower with direct two-tank TES combined with a steam-Rankine power cycle running at 574°C and 41.2% gross efficiency
Design similar to that of 2018 with identified near-term reductions in heliostat and power system costs
2030 Moderate Scenario
Longer-term cost reductions (e.g., in the heliostats and power system)
2030 Advanced Scenario
Low projection based on molten-salt power tower with direct two-tank TES combined with a power cycle running at 700°C and 55% gross efficiency.
Though an advanced molten salt projection is used for the Advanced Scenario, lower costs for baseload CSP are being investigated via different technology options (e.g., solid particle and gas phase towers) and as defined by the DOE Gen3 program ((Mehos et al. 2017); DOE EERE, "Goals of the Solar Energy Technologies Office").
This section describes methodology to develop assumptions for CAPEX, O&M, and capacity factor. Click on these links for standardized assumptions for labor cost, regional cost variation, materials cost index, scale of industry, policies and regulations, and inflation.
For the 2020 ATB, various factors are used to demonstrate the range of LCOE and performance across the United States. These include that:
The CSP costs originated from (1) an NREL survey leading to updated cost estimates in SAM Version 2017.09.05 and (2) further cost estimates for CSP components that have been in SAM from Version 2018.11.11 (Craig Turchi et al. 2019). The SAM 2018 costs translate to ATB costs in 2021 that are due to the three-year construction period. (SAM costs are based on the project announcement year, while the 2020 ATB is based on the plant commissioning year).
Future year projections are informed by the published literature, NREL expertise, and technology pathway assessments for CAPEX and O&M cost reductions. Three projections are developed for scenario modeling as bounding levels:
Definition: For plants whose construction duration exceeds one year, CAPEX costs represent technology costs that lag current-year estimates by at least one year. For CSP plants, the construction period is typically three years.
For the 2020 ATB—and based on key sources ((EIA 2016); (C. Turchi 2010); (Craig Turchi and Heath 2013))—the CSP generation plant envelope is defined to include items noted in the Summary of Technology Innovations by Scenario table above.
In the 2020 ATB, CAPEX does not vary with resource.
Base Year: The CAPEX estimate (with a base year of 2018) is approximately $7,700 kWe in 2018$. It is for a representative power tower with 10 hours of storage and a solar multiple (SM) estimate for a given year represents CAPEX of a new plant that reaches commercial operation in that year (i.e., SAM 2018 CSP costs are reflected in the ATB scenario data in year 2021).
Future Years: Three cost projections are developed for CSP technologies:
Considering currently reported CAPEX for plants either announced or in construction, $6,570/kWe in the ATB in 2021 and $4,880/kWe in 2030 is possible. For example, the Noor III CSP power station in Morocco—a 150-MWe molten salt power tower with 7.5 hours of storage that became operational in 2018—has an estimated CAPEX of $6,500/kWe in 2016$ (Kistner 2016). And the DEWA 700-MWe CSP project in Dubai—a 600-MWe parabolic trough and 100-MWe molten salt tower, each with 12–15 hours of storage, which is in construction—has an estimated bundled CAPEX of $5,500/kWe in 2018$ ((Shemer 2018), (Craig Turchi et al. 2019)).
A range of literature projections is shown in the chart below to illustrate the comparison with the 2020 ATB. When comparing the 2020 ATB projections with other projections, note that there are major differences in technology assumptions, radiation conditions, field sizes, storage configurations, and other factors. As shown in the chart, the ATB 2021 CSP Moderate projection is in line with other recently analyzed projections from other organizations. The Low cost ATB projection is based on the lower bound of the literature sample, and on the Power to Change report (IRENA 2016).
Use the following table to view the components of CAPEX.
Definition: Operation and maintenance (O&M) costs represent the annual expenditures required to operate and maintain a CSP plant over its lifetime, including items noted in the Summary of Technology Innovations by Scenario table above.
Base Year: FOM is assumed to be $68/kW-yr until 2021. Variable O&M is approximately $4.20/MWh until 2021 and $3.60/MWh after that (Kurup and Turchi 2015).
Future Years: Future FOM is assumed to decline to $52/kW-yr by 2030 in the Moderate Scenario (i.e., approximately a 25% drop) and approximately $41/kW-yr by 2030 in the Conservative Scenario based on DOE investments that are likely to help to lower costs (DOE 2012).
Use the following table to view the components of operating expenditures.
Definition: Capacity factors are influenced by power block technology, storage technology and capacity, the solar resource, expected downtime, and energy losses. The solar multiple is a design choice that influences the capacity factor.
Base Year: The 2020 ATB capacity factors are generated from plant simulations using SAM Version 2018.11.11 at the resource locations identified, with 10 hours of storage, and corroborated by operational data:
Operational data from the first and longest-operating molten salt power tower in the world (i.e., the 20-MW Gemasolar plant that includes 15 hours of molten salt TES in Spain, where DNI resource can be considered Class 1, Fair to Class 3, Good) shows a reported capacity factor of 55% (Torresol Energy 2018). Given the higher Good and Excellent DNI resource areas in the United States, a well operating molten salt power tower with 10 hours of TES could reach capacity factors of 60%–64% (SAM Version 2018.11.11).
A key finding of (Murphy et al. 2019) is that if future costs of CSP decrease sufficiently, CSP could be deployed across a greater range of the United States and DNI resources. For example, with aggressive cost decreases and given regional market constraints, southeastern states with lower DNI resources (e.g., Florida and South Carolina) could see increased CSP capacity deployments of up to 5 GWe.
Future Years: The future projections for the Conservative, Moderate, and Advanced technology innovation scenarios are unchanged from the Base Year. Technology improvements are focused on CAPEX and O&M cost elements.
Over time, CSP plant output may decline. Capacity factor degradation that is due to degradation of mirrors and other components is not accounted for in the 2020 ATB estimates of capacity factor or LCOE.
Estimates of capacity factors for CSP in the 2020 ATB represent typical operation. The dispatch characteristics of these systems are valuable to the electric system to manage changes in net electricity demand. Actual capacity factors will likely be influenced by the degree to which system operators call on CSP plants to manage grid services.
The following references are specific to this page; for all references in this ATB, see References.
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IRENA (2016). The Power to Change: Solar and Wind Cost Reduction Potential to 2025. International Renewable Energy Agency. https://www.irena.org/DocumentDownloads/Publications/IRENA_Power_to_Change_2016.pdf
IRENA (2018). Renewable Power Generation Costs in 2017. International Renewable Energy Agency. https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2018/Jan/IRENA_2017_Power_Costs_2018.pdf
Kistner, Rainer (2016). Update on Recent Developments in the CSP Technology. Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH. https://www.giz.de/de/downloads/giz2016_en_CSP%20Update_Abu%20Dhabi.pdf
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Lilliestam, Johan, Labordena, Mercè, Patt, Anthony, & Pfenninger, Stefan. (2017). Empirically Observed Learning Rates for Concentrating Solar Power and their Responses to Regime Change. Nature Energy, 2(7), 17094.
Mehos, Mark, Turchi, Craig, Vidal, Judith, Wagner, Michael, & Ma, Zhiwen. (2017). Concentrating Solar Power Gen3 Demonstration Roadmap. (No. NREL/TP-5500-67464). National Renewable Energy Laboratory. https://www.nrel.gov/docs/fy17osti/67464.pdf
Murphy, Caitlin, Sun, Yinong, Cole, Wesley, Maclaurin, Galen, Turchi, Craig, & Mehos, Mark. (2019). The Potential Role of Concentrating Solar Power Within the Context of DOE's 2030 Solar Cost Targets. (No. NREL/TP-6A20-71912). National Renewable Energy Laboratory. https://www.nrel.gov/docs/fy19osti/71912.pdf
Roberts, Billy J. (2018). Map of Solar Resource in Contiguous United States. National Renewable Energy Laboratory. https://www.nrel.gov/gis/assets/pdfs/solar_dni_2018_01.pdf
Shemer, Nadav (2018). CSP capex costs fall by almost half as developers shift towards China and Middle East. http://newenergyupdate.com/csp-today/csp-capex-costs-fall-almost-half-developers-shift-towards-china-and-middle-east
SolarPACES (2017). DLR Researchers Commission High Temperature Receiver with Ceramic Particle Storage - Solarpaces. https://www.solarpaces.org/dlr-researchers-commission-high-temperature-receiver-ceramic-particle-storage/
SolarPACES (2019). DEWA CSP Trough Project. https://solarpaces.nrel.gov/dewa-csp-trough-project
SolarPACES (2020). CSP Projects Around the World. Solarpaces. https://www.solarpaces.org/csp-technologies/csp-projects-around-the-world/
Taylor, Phil (2016). Nev. Plant Solves Quandary of How to Store Sunshine. E&E Greenwire. https://www.eenews.net/stories/1060034748
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Turchi, C. (2010). Parabolic Trough Reference Plant for Cost Modeling with the Solar Advisor Model (SAM). (No. NREL/TP-550-47605). National Renewable Energy Laboratory. https://www.nrel.gov/docs/fy10osti/47605.pdf
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Turchi, Craig, Boyd, Matthew, Kesseli, Devon, Kurup, Parthiv, Mehos, Mark, Neises, Ty, Sharan, Prashant, Wagner, Michael, & Wendelin, Timothy. (2019). CSP Systems Analysis: Final Project Report. (No. NREL/TP-5500-72856). National Renewable Energy Laboratory. https://www.nrel.gov/docs/fy19osti/72856.pdf
World Bank (2014). Project Appraisal Document on a Proposed Loan in the Amount of EUR234.50 Million and US$80 Million (US$400 Million Equivalent) and a Proposed Loan from the Clean Technology Fund in the Amount of US$119 Million to the Moroccan Agency for Solar Energy with Guarantee from the Kingdom of Morocco for the Noor-Ouarzazate Concentrated Solar Power Plant Project. (No. PAD1007). The World Bank. http://documents.worldbank.org/curated/en/748641468279941398/pdf/PAD10070PAD0P100disclosed0120220140.pdf
Zhipeng, Qi, Wenlong, Chen, Xihua, Wang, & Chengtao, Jing. (2019). Retrofit of Dunhuang 10 MW Molten Salt Plant with a High Temperature Supercritical CO2 Cycle. https://www.solarpaces.org/wp-content/uploads/study-Retrofit-of-Dunhuang-10MW-molten-salt-plant-with-a-high-temperature-supercritical-CO2-cycle.pdf