Go with the flow: Battery system in Bonita to be tested for use in microgrids

Energy storage pilot project extended through the year

A battery storage demonstration project already providing a carbon-free source of electricity to California’s grid is about to be tested to see how well it can work on microgrids.

Located on a bluff at a San Diego Gas & Electric substation in Bonita, the energy storage project uses vanadium redox flow battery technology that stores electricity when the grid has excess supply and then discharges the energy when the power system needs it.

In 2019, the pilot project became the first battery of its kind to be connected to the state’s grid via the California Independent System Operator, which manages the electric system for about 80 percent of the state. The flow batteries in Bonita provide 2 megawatts and 8 megawatt-hours of energy to California’s grid — enough to power about 1,000 homes for up to four hours.

The project’s scope has now been extended through the rest of this year to test its ability to power a microgrid — grids that can disconnect from the power system and operate autonomously.

The project is a joint effort between SDG&E and Japan’s Sumitomo Electric Industries, which grew out of a memorandum of understanding signed in 2015 by the California Governor’s Office of Business and Economic Development and the Japanese government’s New Energy and Industrial Technology Development Organization, which promotes new technologies and funded the cost of the battery system in Bonita.

“The more we can leverage technology, the more we can leverage our operations experience to keep our customers intact” during power shutoffs, said Jonathan Woldemariam, SDG&E’s director of wildfire mitigation and vegetation management. “That’s the goal.”

Utilities in California have increasingly used what are called Public Safety Power Shutoffs, or PSPS, in windy and dry conditions when fire danger is high. Utilities sometimes cut off power to circuits — especially in backcountry areas — to reduce the chances of downed power lines igniting wildfires.

Microgrids can help reduce the effect of PSPS by allowing segments of a service territory to keep the lights on by providing them the ability to operate independently of the grid — to “island,” in the parlance of the industry.

The Sumitomo-designed vanadium redox flow battery at the Bonita substation will be tested by taking about 60 customer accounts that are already connected to the battery system and isolating them for short periods of time to make sure the power seamlessly transitions from the grid to the microgrid.

“We’ll just open a switch while there’s already parallel power so they will not experience interruption” of service, said Laurence Abcede, SDG&E’s distributed energy resources manager.

Abcede said a series of tests will be performed, probably lasting a couple hours at a time. The first tests will probably be conducted at night to see how the batteries perform in the absence of rooftop solar generation, followed by tests during the day to monitor their performance when photovoltaic solar energy is abundant.

Testing is expected to start in the late second quarter. Simulations have been run at SDG&E’s testing facility in Escondido, and Abcede and Woldermariam are optimistic the batteries can do the job.

“We’ve had this vanadium redox flow battery in operation since 2017 with very little glitches,” Woldemariam said. “That gives us some confidence that at least the functionality of the flow battery is going to be good.”

SDG&E has experience installing microgrids, including one in Borrego Springs that keeps power flowing when planned outages and emergencies occur in the desert community. SDG&E last year received a $4.5 million grant from the federal government, aimed at eliminating the use of a pair of diesel generators so the Borrego Springs microgrid can run on 100 percent renewable energy.

With California policymakers setting a target for the state to derive 100 percent of its electricity from zero-carbon resources by 2045, energy storage has taken on a more urgent role in grid management.

Solar production in California is plentiful during the day when the sun is out but disappears after the sun sets. When there is an oversupply of solar during the day, grid managers sometimes have to curtail solar generation. Alternately, they have to rely on sources such as natural gas plants to fill in the gap.

With storage, the energy stored by batteries during the day can be discharged to the grid during peak evening hours when grid is under greater stress and electricity prices are higher. Unlike fossil fuel plants, battery storage emits no carbon.

The energy storage market has been dominated by lithium-ion batteries that store their energy in cells that are stacked atop of each other. SDG&E’s Borrego Springs microgrid, for example, uses lithium-ion batteries.

By contrast, the vanadium redox flow batteries like the one in Bonita, store energy in tanks of liquid electrolytes that are pumped past a membrane to generate a charge. An element commonly used as an alloy for steel, vanadium is available in more ample supplies than lithium.

While flow batteries have shown to have higher startup costs, they can discharge for long durations (six hours or more), offer lifespans of at least 20 years and have the ability to provide service to large, utility-scale projects. Plus, the electrolytes are not flammable, thus avoiding a risk seen with some lithium-ion systems.

“What’s neat about flow batteries is the electrolyte is non-combustible so we can utilize this technology in our wildfire areas and operate it safely,” Abcede said.

The pilot project’s agreement runs through Dec. 28. SDG&E has an option to take ownership of the project then but no decision has been made yet.

Content in the public domain and is for general information purposes only, with no representation, guarantees of completeness, warranty of any kind, express or implied regarding the accuracy, adequacy, validity, availability, completeness, usefulness, or timeliness of any information contained within. Please also excuse any syntax as authors and reposted articles are sourced from global origins. UNDER NO CIRCUMSTANCE SHALL WE HAVE LIABILITY TO YOU FOR ANY LOSS OR DAMAGE OF ANY KIND INCURRED AS A RESULT OF THE USE OF THIS REPOSTED ARTICLE. THE USE OF THIS ARTICLE AND YOUR RELIANCE ON ANY INFORMATION CONTAINED HEREIN IS SOLELY AT YOUR OWN RISK. VANADIUMCORP ALSO ASSUMES NO RESPONSIBILITY OR LIABILITY FOR ANY ERRORS OR OMISSIONS IN THE CONTENT OF THIS ARTICLE.

Continue reading the full story here >>
 

This Post Has 0 Comments

Leave a Reply

Your email address will not be published. Required fields are marked *