Reliable Decarbonized U.S. Electricity Systems

Using a data-driven approach based on 39 years of hourly weather data to derive the variability of the wind and solar resource across the contiguous U.S., we analyze the gaps between supply and historical demand that would be present in an electricity system in which generation was provided by variable wind and solar resources. We then assess the dynamical relationships and in an idealized system assess the cost-effectiveness of various approaches to satisfy resource adequacy planning requirements, including overbuilding and extensive curtailment of variable renewable generation assets, short and long term storage embodied by batteries, flow batteries and power-to-gas-to-power, flexible nuclear generation, and flexible loads such as generation of hydrogen or electrofuels. We additionally have assessed the implications of regionalization of generation assets and load-balancing regions such as California or the Western Interconnect on the needs for flexibility and storage in view of the increased variability and frequency and
duration of resource droughts that occurs as the generation and load-balancing regions are confined geographically. In California, we additionally show that addition of existing hydroelectric generation slightly increases the need for long-duration storage as opposed to decreasing it, due to the seasonal mismatch between hydroelectric generation and electricity demand. The analyses moreover emphasize the need for multi-year planning to ensure resource adequacy in systems that have large contributions of generation from variable renewables.
Bio : Nate Lewis is the George L. Argyros Professor of Chemistry at the California Institute of Technology.  Research interests include phototropism in non-biological inorganic matter and related pattern free nanoscale 3-D lithography.  Lewis is also interested in weather-based data-driven modeling of deeply decarbonized electricity and energy systems based on variable renewable energy as well as technologies for long-term grid storage.