NREL Offers U.S. Power Sector Scenarios with Grid Impacts and Uncertainties


The National Renewable Energy Laboratory‘s (NREL) 2021 Standard Scenarios Outlook is a suite of annually released future scenarios for U.S. power sector evolution through 2050. In its seventh year, the 2021 release includes 50 scenarios capturing a wider range of possible decarbonization pathways than previous years. The latest performs sensitivities around three power sector decarbonization levels to demonstrate how power sector assumptions interact with decarbonization.

“By identifying a range of possible futures for the U.S. electricity sector, we can illuminate specific energy system issues to help inform investment decisions and research priorities,” states Wesley Cole, NREL’s senior analyst and lead author of the 2021 Standard Scenarios Report: A U.S. Electricity Sector Outlook.

“Every year, we fine-tune our scenarios to better represent the potential economic and environmental impacts of future electricity sectors,” Cole adds. “We hope the scenarios are helpful to stakeholders who are navigating and influencing our ever-changing power system.”

Three levels of power sector decarbonization were added to the Standard Scenarios this year due to increased interest in reducing power sector emissions. The first level of decarbonization assumes no new policies are set in place; the second level assumes power sector CO2 emissions decrease to 95% below 2005 emissions by 2050; and the third assumes power sector CO2 emissions decline to 95% below 2005 levels by 2035 and are fully eliminated by 2050. Sensitivities are performed for each decarbonization requirement.

Model results show increased requirements for emissions reduction result in greater renewable energy deployment, particularly for solar photovoltaics (PV) and wind, with some scenarios deploying over 1 TW of solar and 800 GW of wind.

Several key trends emerged across model simulations of the full suite of scenarios. The share of generation from renewable energy grows to 38%–80% in 2050 across the 50 scenarios, with the growth coming primarily from wind and solar. Solar and wind deployment in 2050 across the scenarios is highly sensitive to technology costs, storage deployment, CO2 emission reductions and transmission availability. New transmission build-outs increase with greater renewable energy deployment and higher natural gas prices.

Energy storage also grows across all scenarios, mostly from increased battery deployment – but pumped storage hydropower capacity also increases across most scenarios, doubling by 2050 in many scenarios.

Across the scenarios, there is a big range of natural gas generation in 2050, but natural gas capacity is more consistent. Because natural gas provides valuable firm capacity to the grid, natural gas capacity grows even in scenarios with limited natural gas generation. Coal generation declines over time based on the national emissions limit. Nuclear generation remains steady across most scenarios but grows in scenarios that assume low nuclear technology costs.

The Standard Scenarios are supported by the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy to understand the roles of individual technologies in the larger energy system and market and policy issues that can impact electricity sector evolution.

This work is part of a larger NREL effort to ensure energy analyses incorporate transparent, realistic and timely assumptions and consider diverse potential futures by developing free, open-source data and tools. This includes NREL’s Annual Technology Baseline (ATB) that offers detailed energy technology cost and performance data.

The Standard Scenarios use the latest ATB data and simulations from NREL’s open-source Regional Energy Deployment System (ReEDS) model. ReEDS takes a system-wide, least-cost approach for representing the power sector. Scenarios are selected annually based on a wide breadth of cost and performance trajectories and other drivers under various levels of power sector decarbonization. Scenario assumptions are updated every year to reflect technology, market, and policy changes made in the power sector and to run the latest versions of the ReEDS model. Scenario results are available in the Standard Scenarios Results Viewer.

Read the full Standard Scenarios report here.

Photo by Chelsea on Unsplash

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