Wref2012: the Effect of Large Scale Transmission Limitations on Renewable Energy Load Matching for the Western U.s

The variability of wind and solar energy technologies is perceived as a major obstacle to employing otherwise abundant renewable energy resources. Based on the available geographically dispersed data for the Western U.S. (excluding Alaska), we analyze the extent to which the geographic diversity of these resources can offset their variability. First, we determine the best match to loads that can be achieved with wind power and photovoltaics with no transmission limitations and then impose large-scale transmission limitations to capture regional specifics of load matching with renewables. Without energy storage and assuming unlimited energy flows between regions, wind and PV can meet up to 80% of loads in the Western U.S. while less than 10% of the generated power is curtailed. Limiting hourly energy flows by the aggregated transmission line carrying capacities decreases the fraction of the load that can be met with wind and PV generation to approx. 70%. The fraction of curtailed energy does not increase with the onset of transmission limitations. NOTATION Ct – the amount of curtailed wind and/or PV energy at hour t Ftmn – power flow (MW) from region m to region n at hour t fmn – aggregated power lines capacity (MW) between regions m and n, sets transmission limitations Gt – dispatchable generation from conventional sources at hour t g – upper bound on WECC dispatchable generation capacity (MW) lt – hourly load (electricity consumption) over the WECC area Pj – fraction of the maximum potential built capacity at the PV site j pjt – the input generation that could be produced at hour t by the PV resource at site j 1 Current address: University of Toledo, Toledo, OH WECC Western Electric Coordinating Council; here we consider only the continental U.S. territory, excluding Alaska Wi – fraction of the maximum potential built capacity at the wind site i wit – the input generation that could be produced at hour t by the wind resource at site