This report summarizes the results of 42 forward-looking Standard Scenarios of the U.S. power sector simulated using the Regional Energy Deployment System (ReEDS) and Distributed Generation Market Demand Model (dGen) capacity expansion models. The annual Standard Scenarios, which are now in their fourth year, have been designed to capture a range of possible power system futures considering a variety of factors that impact power sector evolution. The ReEDS and dGen models project utility- and distributed-scale power sector evolution, respectively, for the United States using the Standard Scenarios definitions to specify model inputs. The ReEDS model in particular has been designed with special emphasis on capturing the unique traits of renewable energy, including variability and grid integration requirements. Detailed scenario results at the state level have been included as part of this report at en.openei.org/apps/reeds. Additionally, for a mid-case scenario, the 2050 system built by ReEDS and dGen was run using an hourly production cost model to provide additional temporal detail.
Based on the Standard Scenarios results, this report explores four key themes of U.S. power sector evolution:
• The impacts on system operation from increasing shares of variable renewable energy
• The potential for renewable energy technologies beyond solar photovoltaics (PV) and land-based wind
• The effect of continued natural gas and renewable energy deployment on power sector prices
• The impact of the declining tax credits on renewable energy deployment.
We discuss each of these themes in the context of recent trends and projected changes based on the modeled scenario results. The scenarios include a Mid-case that serves as a reference case (using policies in place as of spring 2018) and 41 side cases that include sensitivities in fuel prices, demand growth, retirements, technology and financing costs, transmission and resource restrictions, and policy considerations. Thirty-nine of the scenarios are classified as non-policy scenarios, because they do not directly consider a policy constraint in the models, and most of the results are presented for only these non-policy scenarios. The three policy scenarios tend to be outliers (e.g., the 80% national renewable portfolio standard scenario always has the highest renewable energy buildout), and therefore these scenarios are not typically discussed when considering ranges across scenarios