Challenges of reaching high renewable fractions in hybrid renewable energy systems

Abstract

This study evaluates the techno-economic feasibility of hybrid renewable energy systems (HRES) for providing electricity in four example localities in the United States: western New York; San Diego, California; Milwaukee, WI; and the entire state of Texas. The Hybrid Optimization of Multiple Energy Resources (HOMER) Pro Microgrid Tool was used to simulate and assess a grid model relying on solar and wind electric generation with utility-scale battery storage as back-up to serve the load on an hourly basis, when renewable resources are not available. A total of 495 HOMER trials were modeled to determine the levelized cost of electricity (LCOE) and societal cost of electricity (SCOE) for each of these locations assuming varying levels of carbon taxes, the economic value of health benefits from emissions savings, and a renewable fraction (RF) ranging from 0% to 100%. Technical and financial properties for the model, such as individual component cost, life-time, and efficiency, were obtained from the U.S. Energy Information Administration (EIA). Emission rates for various generation sources were obtained from the U.S. Environmental Protection Agency (EPA) and health benefits were analyzed using the Co-Benefit Risk Assessment (COBRA) tool. Finally, the ideal renewable fraction resulting in the lowest LCOEs were obtained for each of the four locations studied. For carbon tax values of $0/tonne and $130/tonne, this was determined to be 34% to 48% for New York; 0% to 34% for San Diego; 55% to 75% for Milwaukee; and 21% to 65% for Texas. Applying health benefits can shift the optimal RF of HRESs to higher amounts by 5.26% on average.