Illustrations of solar panels in different locations

The Solar Futures Study explores solar energy’s role in transitioning to a carbon-free electric grid. Produced by the U.S. Department of Energy Solar Energy Technologies Office (SETO) and the National Renewable Energy Laboratory (NREL) and released on September 8, 2021, the study finds that with aggressive cost reductions, supportive policies, and large-scale electrification, solar could account for as much as 40% of the nation’s electricity supply by 2035 and 45% by 2050.  

Line chart showing how the Solar Futures Study predicts that solar deployment will grow from 2020-2050
The Solar Futures Study modeled the deployment of solar necessary for a decarbonized grid. Preliminary modeling shows that decarbonizing the entire energy system could result in as much as 3,000 GW of solar due to increased electrification.

To reach these levels, solar deployment will need to grow by an average of 30 gigawatts alternating current (GWac) each year between now and 2025 and ramp up to 60 GW per year between 2025 and 2030—four times its current deployment rate—to total 1,000 GWac of solar deployed by 2035. By 2050, solar capacity would need to reach 1,600 GWac to achieve a zero-carbon grid with enhanced electrification of end uses (such as motor vehicles and building space and water heating). Preliminary modeling shows that decarbonizing the entire U.S. energy system could result in as much as 3,200 GWac of solar due to increased electrification of buildings, transportation, and industrial energy and production of clean fuels.

The Solar Futures Study is the third in a series of vision studies from SETO and NREL, preceded by the SunShot Vision Study (2012) and On the Path to SunShot (2016). While the previous studies focused on the impacts of low-cost solar technologies on the economy, this study dives into solar energy’s role in a decarbonized grid and provides analysis of future solar technologies, the solar workforce, and how solar energy might interact with other technologies like storage.

Key Findings of the Solar Futures Study

Explore the interactive diagrams for the study’s results and frequently asked questions below.

  • With continued technological advances, electricity prices do not increase through 2035. Ninety-five percent decarbonization of the electric grid is achieved in 2035 without increasing electricity prices because decarbonization and electrification costs are fully offset by savings from technological improvements and enhanced demand flexibility.
  • Achieving decarbonization requires significant acceleration of clean energy deployment, which will employ as many as 500,000–1.5 million people in solar jobs by 2035. Compared with the approximately 15 GW of solar capacity deployed in 2020, annual solar deployment is 30 GW on average in the early 2020s and grows to 60 GW on average from 2025 to 2030. Similarly substantial solar deployment rates continue in the 2030s and beyond. Deployment rates accelerate for wind and energy storage as well.
  • Storage, transmission expansion, and flexibility in load and generation are key to maintaining grid reliability and resilience. Storage capacity expands rapidly, to more than 1,600 GW in 2050. Small-scale solar, especially coupled with storage, can enhance resilience by allowing buildings or microgrids to power critical loads during grid outages. In addition, advances in managing distributed energy resources, such as rooftop solar and electric vehicles, are needed to efficiently integrate these resources into the grid.
  • Expanding clean electricity supply yields deeper decarbonization. Electricity demand grows by about 30% from 2020 to 2035, owing to electrification of fuel-based building demands (e.g., heating), vehicles, and industrial processes. Electricity demand increases by an additional 34% from 2035 to 2050. By 2050, all these electrified sectors are powered by zero-carbon electricity, and the electrification growth results in an emissions reduction equivalent to 155% of 2005 grid emissions.
  • Land availability does not constrain solar deployment. In 2050, ground-based solar technologies require a maximum land area equivalent to 0.5% of the contiguous U.S. surface area. This requirement could be met in numerous ways, including the use of disturbed or contaminated lands unsuitable for other purposes.
  • The benefits of decarbonization far outweigh additional costs incurred. Cumulative power system costs from 2020 to 2050 are $562 billion (25%) higher, which includes the costs of serving electrified loads previously powered through direct fuel combustion. However, avoided climate damages and improved air quality more than offset those additional costs, resulting in net savings of $1.7 trillion.
  • Challenges must be addressed so that solar costs and benefits are distributed equitably. Solar deployment can bring jobs, savings on electricity bills, and enhanced energy resilience. Various interventions—financial, community engagement, siting, policy, regulatory, and resilience measures—can improve equity in rooftop solar adoption. Additional equity measures can address the distribution of public and private benefits, the distribution of costs, procedural justice in energy-related decision making, the need for a just workforce transition, and potential negative externalities related to solar project siting and disposal of solar materials.

Grid mixes and energy flows in 2020 and 2050 as envisioned in the Solar Futures Study. Newly electrified loads from the buildings, transportation, and industrial sectors mean that the electric grid will deliver more energy in 2050. This energy will come almost entirely from solar and other zero-carbon sources.

The Decarbonization with Electrification scenario will reduce grid emissions (relative to 2005 levels) by 95% in 2035 and 100% in 2050 and replace some direct fossil fuel use in the buildings, transportation, and industrial sectors, allowing it to abate more than 100% of 2005 grid emissions.

  • Three scenarios were modeled with different assumptions – the “Reference” scenario, the “Decarbonization (Decarb)” scenario, and the “Decarbonization with Electrification (Decarb+E)” scenario.
  • The Reference scenario outlines a business-as-usual future, which includes existing state and federal clean energy policies but lacks a comprehensive effort to decarbonize the grid.
  • The Decarb scenario assumes policies drive a 95% reduction (from 2005 levels) in the grid’s carbon dioxide emissions by 2035 and a 100% reduction by 2050. This scenario assumes more aggressive cost-reduction projections than the Reference scenario for solar, as well as other renewable and energy storage technologies, but it uses standard future projections for electricity demand.
  • The Decarb+E scenario goes further by including large-scale electrification of end uses and analyzes the potential for solar to contribute to a future with more complete decarbonization of the U.S. energy system by 2050.

  • By 2035 (95% decarbonization), the decarbonization scenarios show cumulative solar deployment of 760 GW–1,000 GW would be required, serving 37%–42% of electricity demand. The remainder is met largely by other zero-carbon resources, primarily wind and also including nuclear, hydroelectric, biopower, and geothermal power.
  • By 2050 (100% decarbonization), the scenarios envision cumulative solar deployment of 1,050 GW–1,570 GW would be required, serving 44%–45% of electricity demand. The remainder is met primarily by wind but also nuclear, hydropower, combustion turbines run on zero-carbon synthetic fuels such as hydrogen, biopower, and geothermal power.
  • In 2020, about 76 GW of solar satisfied around 3% of U.S. electricity demand.

  • The Solar Futures Study explores the role of solar in grid decarbonization, and this role is essentially the same regardless of whether the goal is 95% or 100% by 2035.
    • However, achieving 95% vs. 100% grid decarbonization by 2035 entails substantial differences in costs and the need for other clean energy technologies.
    • In the Decarb+E scenario, an expanded grid electrifies additional end uses (such as motor vehicles and space and water heating in buildings) that had derived energy directly from fossil fuels. In 2035, the grid is 95% decarbonized, but the additional fossil fuel displacement yields total emissions reductions equivalent to a grid that is 105% decarbonized—more cost-effectively than could be achieved by completely eliminating grid emissions in this time frame. These results show the importance of considering flexible, cross-sector approaches to optimizing the speed and cost-effectiveness of overall emissions reductions.

  • Expanded electrification of the U.S. energy system in the Decarb+E scenario contributes to reducing energy system carbon dioxide (CO2) emissions by 62% in 2050, compared with 24% in the Reference scenario and 40% in the Decarb scenario (relative to 2005 levels).
  • A simplified analysis of 100% decarbonization of the U.S. energy system by 2050 shows solar capacity doubling from the Decarb+E scenario—to about 3,200 GW of solar deployed by 2050—to produce electricity for even greater direct electrification and for production of clean fuels, such as hydrogen produced via electrolysis.

  • Solar can facilitate deep decarbonization of the U.S. grid by 2035 without increasing projected 2035 electricity prices if targeted technological advances are achieved.
    • Decarbonization and electrification costs are fully offset by savings from technological improvements and enhanced demand flexibility through 2035 (95% decarbonization).
    • Projected electricity prices are higher in the decarbonization scenarios than in the Reference scenario in 2050 because of higher costs for eliminating emissions by 100%—highlighting the need for technology advancements and decarbonization options beyond those modeled in the scenarios.
  • For the 2020 to 2050 period, the benefits of the decarbonization scenarios far outweigh additional costs. Cumulative system costs are higher in the Decarb (10%) and Decarb+E (25%) scenarios than in the Reference scenario, but avoided climate damages and improved air quality more than offset those additional costs, resulting in net savings of $1.1 trillion in the Decarb scenario and $1.7 trillion in the Decarb+E scenario.
  • There is greater uncertainty related to costs and benefits in the period out to 2050, compared with the 2035 timeframe.

  • Although land acquisition poses challenges, land availability does not constrain solar deployment in the scenarios.
    • In 2050, ground-based solar technologies require a maximum land area equivalent to 0.5% of the contiguous U.S. surface area, which could be met in numerous ways including use of disturbed or contaminated lands unsuitable for other uses. The maximum solar land area required is equivalent to less than 10% of potentially suitable disturbed lands, avoiding conflicts with high-value lands in current use.
      • This analysis does not consider land used for other technologies that generate electricity in the scenarios or transmission infrastructure.  
    • Various approaches are available to mitigate local impacts or even enhance the value of land that hosts solar systems. Installing photovoltaic (PV) systems on water bodies, in farming or grazing areas, and in ways that enhance pollinator habitats are potential ways to enhance solar energy production while providing benefits such as lower water evaporation rates and higher agricultural yields.
    • Expanding rooftop PV could reduce solar land use. Almost 200 GW of rooftop PV are deployed in the decarbonization scenarios by 2050 (10%–20% of total solar deployment). However, the technical potential for U.S. rooftop PV is greater than 1,000 GW, and efforts to promote rooftop PV could increase deployment beyond the modeled level.

  • Material supplies related to technology manufacturing likely will not limit solar growth in the decarbonization scenarios, especially if end-of-life materials displace use of virgin materials via circular-economy strategies.

  • A lot of materials will be used to produce solar technologies in the scenarios, but a range of strategies—such as reduced material intensity, recycling, repair, and reuse—can mitigate their impact of materials when the technologies reach the end of their planned lifetimes (typically 30 years for PV modules).
  • Governments, industry, and associated stakeholders can begin preparing now for more solar materials reaching the end of their useful life by identifying technical solutions for end-of-life management, reducing recycling costs, maximizing value from recovered materials, matching recovered materials with markets, partially offsetting material demands for solar manufacturing via recovered materials, and so forth.

  • Achieving the decarbonization scenarios requires significant but achievable acceleration of clean energy deployment.
    • Compared with the 15 GW of solar capacity deployed in 2020, annual solar deployment doubles in the early 2020s and quadruples by the end of the decade in the Decarb+E scenario. Similarly substantial solar deployment rates continue in the 2030s and beyond. Deployment rates accelerate for wind and energy storage as well.
    • Clean energy growth during the past decade indicates the scalability of clean technology industries. Global solar deployment rates have exceeded the U.S. rates in the Solar Futures scenarios, and very high annual deployments of other technologies have occurred historically. Still, increased and sustained deployment of solar and other clean technologies will require substantial scale-up of solar manufacturing, supply chains, and the workforce.

  • Continued technological progress is critical to achieving the Solar Futures vision, and there are multiple pathways toward it.
    • Research and development can help keep technologies on current or accelerated cost-reduction trajectories. For example, a 60% reduction in PV energy costs by 2030 could be achieved via improvements in PV efficiency, lifetime energy yield, and cost. Higher-temperature, higher-efficiency concentrating solar-thermal power technologies also promise cost and performance improvements.
    • Further advances are also needed in areas including energy storage, load flexibility, generation flexibility, and inverter-based resource capabilities for grid services.

  • From 2020 to 2050, interregional transmission expansion increases by 60% (86 terawatt-miles) in the Decarb scenario and 90% (129 terawatt-miles) in the Decarb+E scenario.

  • The solar industry already employs around 230,000 people in the United States, and with the level of growth envisioned in the Solar Futures Study’s scenarios, it could employ 500,000–1.5 million people by 2035.

  • The study models utility-scale as well as distributed/rooftop solar. In the Decarb and Decarb+E scenarios, we project that up 200 GW of rooftop PV are deployed by 2050 (10%–20% of total solar deployment). 
  • The study's primary conclusion is that decarbonizing the electricity grid will require approximately 1,000 GW of solar.  The exact mix of utility vs. distributed solar will depend on many factors, including ability to expand transmission, as well as policies designed to encourage adoption of rooftop solar. 
  • The study does not include any policies specifically targeted at increasing the adoption of distributed PV. Given that the technical potential of U.S. rooftop PV is greater than 1,000 GW, policies to promote rooftop PV could increase deployment beyond the level modeled in the study.  

  • Low- and medium-income communities and communities of color have been disproportionately harmed by the fossil-fuel-based energy system, and the clean energy transition presents opportunities to mitigate these energy justice problems by implementing measures focused on equity.
  • Solar deployment can bring jobs, savings on electricity bills, and enhanced energy resilience. Various interventions—financial, community engagement, siting, policy, regulatory, and resilience measures—can improve equity in solar adoption. 
  • The distribution of benefits and costs will not necessarily occur equitably, and addressing this challenge may require targeted policies and structural change.
  • This study explores measures related to the distribution of public and private benefits, the distribution of costs, procedural justice in energy-related decision making, the need for a just workforce transition, and potential negative externalities related to solar project siting and disposal of solar materials.

Additional Resources