Abstract
With the growing need for decarbonization, microgrids that independently produce carbon-neutral power will become an important part of the solution. An analytical model has been developed based on the historical demand at Southwest Research Institute (SwRI). This model incorporates general energy production and storage technologies into a flexible framework for assessment of scenarios for a microgrid. For solar photovoltaics (PV), the model incorporates time-series renewable data on solar PV performance from the NREL System Advisor Model (SAM). The capital cost and operating cost information for storage and generation were sourced from public studies and were escalated to 2023 costs using inflation. Using these inputs, the analytical model projects the 30-year performance of the power generating system and applies economic parameters to establish a blended cost of electricity that is a levelized cost of electricity (LCOE) for the capital and operating cost of behind the meter assets along with any purchased electricity or natural gas from utilities. A variety of electricity producing technologies were examined, including PV, gas generator with carbon capture and storage (CCS), lithiumion battery, hydrogen production and utilization, and pumped thermal energy storage. For shifting PV generation in daily cycles, the storage systems were implemented as long-duration energy storage (LDES) with a minimum duration of 6 hours.
The trends in blended electric cost showed how electric energy consumed on the SwRI campus can be decarbonized by 40%, while reducing costs by about 12% through the addition of behind the meter PV generation alone. Adding storage to utilize curtailed PV increased system cost, but it improved decarbonization to 55% before reaching parity with present electric costs. Reaching 90% decarbonization with PV and LDES came at the cost of an additional 37% increase of blended costs. The trends showed that costs beyond 90% decarbonization increase dramatically because LDES became very large to balance longer trends in PV power production and reach 100% decarbonization. A combined system that installed a gas generator with CCS showed how the last 10% of decarbonization can be achieved without the dramatically escalating costs of a PV with LDES system alone beyond 90%.
