The Annual Energy Outlook explores long-term energy trends in the United States
- Projections in the Annual Energy Outlook 2021 (AEO2021) are not predictions of what will happen, but rather, they are modeled projections of what may happen given certain assumptions and methodologies. By varying those assumptions and methodologies, AEO2021 can illustrate important factors in future energy production and use in the United States.
- Energy market projections are uncertain because many of the events that shape energy markets—as well as future developments in technologies, demographics, and resources—cannot be foreseen with certainty. To illustrate the importance of key assumptions, AEO2021 includes a Reference case and side cases that systematically vary important underlying assumptions.
- The U.S. Energy Information Administration (EIA) develops the AEO by using the National Energy Modeling System (NEMS), an integrated model that captures interactions of economic changes and energy supply, demand, and prices.
- The AEO is published to satisfy the Department of Energy Organization Act of 1977, which requires EIA’s Administrator to prepare annual reports on trends and projections for energy use and supply.
What is the AEO2021 Reference case?
- The AEO2021 Reference case represents EIA’s best assessment of how U.S. and world energy markets will operate through 2050, based on key assumptions intended to provide a baselinefor exploring long-term trends.
- The Reference case serves as a reasonable baseline case that can be compared with the sidecases that include alternative assumptions.
- EIA based the economic and demographic trends reflected in the Reference case on the current views of leading economic forecasters and demographers. For example, the Reference case projection assumes improvement in known energy production, delivery, and consumption technologies.
- The Reference case generally assumes that current laws and regulations that affect the energy sector, including laws that have end dates, remain unchanged throughout the projection period. This assumption enables EIA to use the Reference case as a benchmark to compare with alternative policy-based cases.
- The potential effects of proposed legislation, regulations, or standards are not included in the AEO2021 cases.
What are the side cases?
- Global market balances, primarily influenced by factors that are not modeled in NEMS, will drive future oil prices. In the AEO2021 High Oil Price case, the price of Brent crude oil, in 2020 dollars, reaches $173 per barrel (b) by 2050, compared with $95/b in the Reference case and $48/b in the Low Oil Price case.
- Compared with the Reference case, the High Oil and Gas Supply case reflects lower costs and greater resource availability for oil and natural gas in the United States, which allows for more production at lower prices. The Low Oil and Gas Supply case assumes fewer resources and higher costs.
- The High Economic Growth case and Low Economic Growth case address the effects of economic assumptions on the energy consumption modeled in the AEO2021. The two cases assume compound annual growth rates for U.S. gross domestic product of 2.6% and 1.6%, respectively, from 2020 to 2050, compared with 2.1% per year growth in the Reference case.
- The High Renewables Cost case and the Low Renewables Cost case examine the sensitivities surrounding capital costs for renewable electric power generating technologies. Capital cost reduction for an electric power generating technology is assumed to occur from learning by doing. The High Renewables Cost case assumes no cost reduction from learning for any renewable technologies. The Low Renewables Cost case assumes higher learning rates for renewable technologies through 2050, resulting in a cost reduction of about 40% from the Reference case by 2050.
Takeaways from the Reference and side cases
Returning to 2019 levels of US energy consumption takes years; energy related carbon dioxide emissions fall further before leveling off or rising
- Energy consumption fell faster than gross domestic product in 2020, and the pace at which both will return to 2019 levels remains uncertain.
- Petroleum remains the most-consumed fuel in the United States, as energy-related carbon dioxide emissions dip through 2035 before climbing in later years.
- The energy intensity of the U.S. economy continues to fall as end-use sector intensities decline at varying rates.
Renewable energy incentives and falling technology costs support robust competition with natural gas as coal and nuclear power decrease in the electricity mix
- Electricity demand grows at a modest rate throughout the projection period.
- As coal and nuclear generating capacity retires, new capacity additions come largely from natural gas and renewable technologies.
- Renewable electricity generation increases more rapidly than overall electricity demand through 2050.
- The cost-competiveness of solar photovoltaic and natural gas combined-cycle units leads to capacity additions.
Continuing record-high domestic energy production supports natural gas exports but does not necessarily mean growth in the US trade balance in petroleum products
- Amid uncertainty, the United States continues to be an important global supplier of crude oil and natural gas.
- Motor gasoline remains predominant despite a growing mix of technologies in passenger vehicles.
- Natural gas consumption growth between 2020 and 2050 is concentrated in two areas: exports and industrial use.
- The amount of crude oil processed at U.S. refineries decreased in 2020 because of lower demand for transportation fuels, but it returns to 2019 levels by 2025.
- Consumption of biofuels as a share of the domestic fuel mix increases in AEO2021.
Previous Editions of the AEO
Documentation and Assumptions