Features of a fully renewable US electricity system: Optimized mixes of wind and solar PV and transmission grid extensions

摘要

Wind and solar PV generation data for the entire contiguous US arecalculated, on the basis of 32 years of weather data with temporal resolutionof one hour and spatial resolution of 40x40km$^2$, assumingsite-suitability-based as well as stochastic wind and solar PV capacitydistributions throughout the country. These data are used to investigate afully renewable electricity system, resting primarily upon wind and solar PVpower. We find that the seasonal optimal mix of wind and solar PV comes ataround 80% solar PV share, owing to the US summer load peak. By picking thismix, long-term storage requirements can be more than halved compared to a windonly mix. The daily optimal mix lies at about 80% wind share due to the nightlygap in solar PV production. Picking this mix instead of solar only reducesbackup energy needs by about 50%. Furthermore, we calculate shifts in FERC(Federal Energy Regulatory Commission)-level LCOE (Levelized Costs OfElectricity) for wind and solar PV due to their differing resource quality andfluctuation patterns. LCOE vary by up to 35% due to regional conditions, andLCOE-optimal mixes turn out to largely follow resource quality. A transmissionnetwork enhancement among FERC regions is constructed to transfer highpenetrations of solar and wind across FERC boundaries, based on a novelleast-cost optimization approach.