The value of CO2-Bulk energy storage with wind in transmission-constrained electric power systems

High-voltage direct current (HVDC) transmission infrastructure can transmit electricity from regions with high-quality variable wind and solar resources to those with high electricity demand. In these situations, bulk energy storage (BES) could beneficially increase the utilization of HVDC transmission capacity. Here, we investigate that benefit for an emerging BES approach that uses geologically stored CO2 and sedimentary basin geothermal resources to time-shift variable electricity production. For a realistic case study of a 1 GW wind farm in Eastern Wyoming selling electricity to Los Angeles, California (U.S.A.), our results suggest that a generic CO2-BES design can increase the utilization of the HVDC transmission capacity, thereby increasing total revenue across combinations of electricity prices, wind conditions, and geothermal heat depletion. The CO2-BES facility could extract geothermal heat, dispatch geothermally generated electricity, and time-shift wind-generated electricity. With CO2-BES, total revenue always increases and the optimal HVDC transmission capacity increases in some combinations. To be profitable, the facility needs a modest $7.78/tCO(2) to $10.20/tCO(2), because its cost exceeds the increase in revenue. This last result highlights the need for further research to understand how to design a CO2 BES facility that is tailored to the geologic setting and its intended role in the energy system.

Automated summary

Research shows that utilizing geologically stored CO2 and sedimentary basin geothermal resources in a BES facility can increase the utilization of HVDC transmission capacity, thereby raising total revenue. This type of facility requires a cost of $7.78/tCO2 to $10.20/tCO2 to be profitable.