Integrating Solar and Wind Power to Replace Coal in Texas

Abstract:

Texas generates more wind power than any other state and has a rapidly growing solar industry, but also leads the nation in coal combustion and associated emissions. In a 2018 paper, we quantified the complementary nature of wind and solar power in the state, with West Texas winds blowing most strongly at night, South Texas sea breezes peaking on summer afternoons, and solar power peaking midday. That complementarity could enable solar and wind farms to provide steadier output to replace the power from coal plants.

In our latest analysis to be presented here, we compute the half-hourly power generation that could be produced by each wind and solar farm in the ERCOT interconnection queue. We use NREL’s System Advisor Model to model the output of proposed wind and solar farms based on weather data for the years 2009-2011. We then explore the extent to which recent coal generation in ERCOT could be replaced with power from those proposed facilities. Through optimization modeling, we identify combinations of wind and solar sites that are best suited to displacing various percentages of the power load currently provided by coal. Annualized costs of the wind and solar farms are compared to the direct and societal costs of continuing to operate the coal plants. Preliminary results suggest that over 95% of coal generation can be directly replaced by wind and solar power, even without the use of storage, at a small fraction of the annual cost of coal.