Energy Storage Systems and EV Fleets Managed Together
To Relieve Grid Pressure and Optimize Times for Charging
San Diego Gas & Electric is in its “fifth-generation” of electric vehicle grid integration, with three company and two customer fleets of electric vehicle participating in the latest pilot initiative. Because the EV operators agree to charge at the best time for the grid and the wholesale markets for electricity, the EVs are seen as assets rather than loads on the system. Further, the fleet operators are able to charge their EVs when electricity costs are lowest.
SDG&E says it is “actively bidding” a group of energy storage systems and the five EV fleets as one resource directly into CAISO, the California Independent System Operator’s energy markets. Among other roles, the markets help address short-term imbalances in electricity supply.
“This pilot project emphasizes SDG&E’s focus on innovation in the electric vehicle and energy storage sectors,” SDG&E senior power supply VP Jim Avery says in a release.
“There is tremendous potential for dispatchable distributed energy resources to enhance reliability and achieve greater efficiencies,” he said. “The key to unlocking that potential is to better understand how these resources provide value both at the customer site level and at the larger electric grid level. This project does just that.”
“This is a first of its kind in California,” Avery told F&F. He also told F&F that the two customer fleets have asked that their identities be withheld because they see a competitive advantage in their program participation – they are saving even more on fuel (the electricity they buy) than their competitors.
Assets in addition to the EVs include solar panels and battery storage units. “The assets are remotely controlled using software that both balances the participant’s charging needs, and identifies opportunities to provide demand response services at the grid level,” the utility says. “Demand response is when customers don’t charge EVs or consume energy at peak hours, which alleviates stress on the grid and helps make sure adequate resources are available for the entire region.
Charging Tied to Pricing
“The project achieves this by correlating charging activity with wholesale energy prices. By agreeing to not charge in certain high price hours, the aggregated resource is paid the marginal energy price in those hours, similar to a conventional generator.”
“Creating a framework for small, aggregated resources to directly participate in energy markets is a natural evolution of SDG&E’s earlier, pioneering efforts at the San Diego Zoo and Borrego Springs Microgrid,” Avery says in the announcement. “Those innovative projects demonstrated that aggregating diverse resources like solar, energy storage and EVs, created efficiencies and enhanced reliability.”
EVs Necessitate Innovative Rate Structures
There are currently more than 13,000 EVs in SDG&E’s service territory – “We’ve got more electric vehicles than any city in the world,” Avery says. Managing their charging loads “necessitates innovative rate structures that encourage charging at optimal times and minimize system impacts at the local distribution level,” the utility says.
“Addressing these broader infrastructure additions and rate reform requirements is the subject of SDG&E’s Electric Vehicle Grid Integration (EVGI) Pilot Program.”
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Source: San Diego Gas & Electric with Fleets & Fuels follow-up