An energy storage pilot project in Minneapolis will help test a vision for how homeowners might someday share solar power directly with neighbors.
Each of the four batteries being installed at the Regional Apprenticeship Training Center in North Minneapolis will represent a household — two with solar panels and two without. The batteries will continuously buy and sell power from each other based on a predetermined set of rules.
It’s one of the country’s first “virtual power plant” pilot projects, according to Jamez Staples, founder of solar developer Renewable Energy Partners and the green jobs training center that hosts the project.
Today residential solar customers either consume the power they generate on site or sell the excess generation to their utilities through net metering programs. Staples’ research battery pilot will study how a market could develop where households or businesses share power without going through a utility. It will also provide backup to the training center.
Staples sees batteries as the next evolution of clean energy, and one that will create jobs. “Battery storage will create further integration of the clean energy revolution that is taking place,” he said. “People are becoming more and more aware of these technologies. Solar is the first element, battery storage is the second, and electric vehicles are the third.”
Renewable Energy Partners’ operations manager Nate Broadbridge said the pilot “will showcase how your neighbors can share their energy between each other that can actually be measured and tracked, and based on your household consumption, battery storage, the solar energy you have.”
The pilot is one of three battery projects sponsored by the University of Minnesota’s Institute on the Environment and paid for by a $550,000 grant from the Minnesota Environment and Natural Resources Trust Fund. Red Lake Nation and the University of Minnesota Morris will also install battery storage systems using money from the trust fund.
The other two projects are waiting for delivery of Chinese-made “flow” batteries that have been held up by supply chain issues. Staples opted for lithium-ion batteries instead because the German firm Sonnen’s battery package offered the ability to create a virtual power plant.
Staples and his staff say the Sonnen came highly recommended from a local electric company it works with on projects. Renewable Energy Partners felt more comfortable with lithium-ion batteries that underlies most electricity storage projects today, although flow technology has gained a small slice of the market. Xcel engineers agreed to help design the batteries’ installation, which will be the first Sonnen models on the utility’s grid, he said.
The initiative joins a growing list of battery projects underway in Minnesota. Great River Energy and Form Energy will debut in 2023 an “iron air” battery that has captured national attention. Connexus Energy, a cooperative, has operated a solar-storage project since 2019. Several nature centers installed small battery projects, and on a larger scale, Xcel Energy’s integrated resource plan calls for hundreds of megawatts of storage.
Michael Krause, a consultant who works with Renewable Energy Partners, worked with a local electric company to select Eco batteries manufactured by the German firm Sonnen. The four batteries will store a total of 20 kilowatts. A section of the rooftop’s solar array connects directly to the batteries and draws electricity from individual panels.
“It’s as if this was a neighborhood with four separate battery facilities,” Krause said. “The idea is that we’re going to test out the virtual power plant model, the kind of peer-to-peer sales model. … It’s really what the energy grid is going to very likely look like in the next five to 10 years.”
Every fictional home will have battery storage, but only two have solar panels producing energy. One solar-owning home — the generous neighbor — shares abundant energy production. The other solar producer — the selfish neighbor — only shares after the load is covered and battery charged.
“What we’re trying to prove is that it is possible to program your system to buy and sell energy based on things like time of day and your neighbors’ preferences on how they want to consume their electricity, whether from solar or a battery or the grid,” Broadbridge said.
Shree Pandey, a master electrician with Sundial Energy, is installing the batteries. “It’s been challenging because this is a commercial building and the battery is set up for residential PV [photovoltaic] solar storage,” he said. “It’s been hard to make it work.”
Outside of the experiment of trading stored electricity, the battery has other functions. The pilot will help inform a proposal to build a substantial microgrid in the neighborhood, one of the largest in the Twin Cities. Renewable Energy Partners will install a 1.3-megawatt solar project on three schools in the community in partnership with Minneapolis Public Schools.
Xcel Energy has agreed to own and operate a 500-kilowatt battery connected to the solar installations to create a microgrid designed to serve as a “community resiliency hub,” Krause said. “It’ll be capable of operating at a certain level, even if there’s a major and extended grid emergency.”
Staples see education as another critical aspect of the storage project. North Minneapolis residents taking classes for jobs in the construction industry and clean energy economy will learn how to install batteries and how they function within homes and businesses, Staples said. “Our goal for this building is to make sure that the training necessary for this population, the residents of this neighborhood and surrounding areas have the assets they need to find jobs,” he said.