San Diego, Calif. — How does the grid value energy storage? What are the actual costs of grid smoothing, reliability and other services that a given amount of energy storage can offer? The answers to these questions may be a bit more transparent this Fall after the California Independent System Operator (CAISO) conducts a two-month market simulation of their grid territory beginning in September, including a test of the supply of commercial-scale energy storage services by the University of California at San Diego.
“The CAISO will be evaluating the cost of the grid support and subsequently have a better idea of how to value it,” says William Torre, the program director for energy storage systems at the Center for Energy Research within the Jacobs School of Engineering at UCSD. Torre was a speaker at the Renewable Energy Storage Symposium that took place in San Diego last week.
UCSD possess what may be the largest installation of energy storage projects among all universities in the United States, with close to five megawatts of capacity. Encompassing a variety of technologies, the institution has developed these demonstration projects, often with commercial companies and/or U.S. Department of Energy grants, to show commercial viability. Overall, the university has an annual research budget of around $1 billion, including substantial renewable energy projects.
UCSD saves close to $800,000 a year in avoided electricity costs through the use of its energy storage capabilities and careful energy management of its near-island microgrid. The school can self-generate up to 92 percent of its 42-MW peak load from biogas, fuel cells and solar assets. Through its energy control management system, the controllers can cut 6 MW of energy consumption, largely through temperature controls in campus buildings, with the push of a button. “So San Diego Gas & Electric asks us once in a while to drop consumption for 30 minutes or an hour, and we make some extra money,” Torre said.
Eight separate projects comprise the school’s energy storage capabilities, including lithium-ion batteries, zinc-bromine flow batteries, used electric vehicle batteries, fuel cells and ultracapacitors. Private partners in these projects include Sanyo, Panasonic, Maxwell, and a variety of renewable energy companies and laboratories, like NREL. The software for the school’s microgrid control system was originally written by EPRI, and is open source.
Most recently the university put out an RFP for a 2.5-MW battery storage system that was chemistry agnostic; the winner is expected to be announced in a matter of weeks once the contract if finalized. This project is being funded by the California Public Energy Commission’s Self-Generation Incentive Program (SGIP). The goal of the project is to link the school's photovoltaic and fuel cell assets with tasks of campus cooling, demand reduction, and peak shifting. The minimum system requirement for the winning system is a 64 percent efficient technology that can perform 3,000 cycles of deep discharge.
“We are rethinking the paradigm of how to design an energy efficient island community with microgrids, energy storage and demand response capability, which may be more efficient than the grid going forward,” Torre explained. In such a future world, the grid would be a backup.
More demonstrations like the CAISO test of the university’s ability to coordinate disparate components of renewable energy generation with grid-supplied energy, energy storage and demand control will help accelerate the commercial adoption of energy storage not only by end user entities but also by utilities and grid operators.
Lead image: Clock tower San Diego via Shutterstock