Sustainable: Batteries bolster solar in a first for Minnesota
Connexus Energy’s 18-acre site in Ramsey has nearly 14,000 solar panels alongside 1,260 batteries holding 6 megawatts of electricity. (Photo by: Connexus Energy)
By Frank Jossi
The revolution underway in clean energy is taking a big step forward this month as Connexus Energy switches on Minnesota’s first major project pairing solar panels with battery storage. At locations in the Athens Township and Ramsey, the electric cooperative will capture solar energy and store it in lithium iron phosphate battery installations nearby. The stored energy will be delivered back into Connexus’ grid during the high-demand time of late afternoon and early evening, when customers return home after work and school.
In the more than two years the Ramsey-based cooperative took to lease land, write contracts with vendors and prepare its system, the project’s cost dropped by half as battery prices plummeted. The solar installations in the $31 million project add 10 megawatts of renewable energy to the Connexus grid, and the battery storage holds 15 megawatts of electricity.
The company begins saving money the first month we begin operations.
“The company begins saving money the first month we begin operations,” said Brian Burandt, vice president of power supply.
Burandt spoke Nov. 16 at an energy-storage conference held in St. Paul by the Environmental Initiative. He noted interest in the Connexus project has been so widespread that he’s delivered presentations on it at least five times over the past few months.
The major reason is that Connexus’ project is first “solar plus storage” initiative in the Midwest and one of the few in the country, though that’s about to change dramatically.
“Battery storage is going to be a big enabler in goals we have for our energy system,” said Ellen Anderson, executive director of the University of Minnesota’s Energy Transition Lab, in an interview after the conference. “If you’re doing high amounts of renewable energy, you need storage. If you want to reduce peak demand, storage is a really good tool for that and can help utilities avoid building more [power plants].”
In Colorado, Minneapolis-based Xcel Energy — the utility serving much of that state’s most populous areas — plans 275 megawatts of battery storage paired with solar. California regulators recently approved contracts for 567 megawatts of battery storage for Pacific Gas & Electric Co. north of Monterrey.
Besides Connexus, Minnesota’s solar-battery storage projects have been largely small pilots at OATI Inc. in Bloomington, the Hartley Nature Center in Duluth and the University of St. Thomas in St. Paul.
Despite having only a handful of projects, Minnesota has the right mix of renewable energy and interest in technology to become a leader in energy storage, according to several speakers at the Environmental Initiative conference. Anderson said the state’s high penetration of renewable energy — 25 percent of electricity comes from renewable sources — makes it a strong candidate for battery storage.
“Minnesota is a model, and can be a model, and help shape the global landscape for battery storage,” Anderson said. Reaching Minnesota’s ambitious goal of reducing carbon by 80 percent by 2050 will require a more aggressive investment in storage totaling thousands of megawatts.
The Minnesota Department of Commerce’s “Solar Pathways” report, released last month, suggests Minnesota could generate 70 percent of its electricity from wind and solar by 2050. To reach that amount, the state will need anywhere from 4 to 25 gigawatts of storage, an unimaginably large number today yet considered achievable over the decades-long timeline.
At the conference, Anderson pointed out storage is not just about batteries. One approach, pumped hydro, releases water from an elevated reservoir to a lower one, with turbines capturing the energy released. A 2011 report from the University of Minnesota-Duluth’s Natural Resources Research Institute suggested Mesabi Iron Range mining sites could serve as pumped-hydro energy-storage sites.
Another approach, thermal storage, has been tried with success by the generation and transmission cooperative Great River Energy, which serves 28 member cooperatives. Thousands of customers of Great River’s cooperatives participate in a program that warms their electric water heaters at night, when energy is cheap, and shuts them off during the day.
The greatest interest and action, however, is clearly taking place around battery storage. Xcel Energy, the state’s largest investor-owned utility, is a national leader in renewable energy and plans to generate 60 percent of its electricity needs from renewable energy by 2030 in Minnesota, said public policy and strategy manager Julia Eagles.
Energy storage has many applications, from enhancing utility operations to optimizing power systems and improving customer experiences. Driving energy storage adoption is the demand for a grid capable of absorbing variable energy from wind and solar, Eagles said.
For now, Xcel’s battery initiative focuses on Colorado, where it received bids from 97 separate projects for storage and is building two. “The timing was good for our costs,” she said, as battery prices have fallen. McKinsey & Company reports battery prices dropped 15 percent per year from 2012 to 2017, or more than 50 percent; the cost of installation declined 25 percent annually during the same time period.
Closer to home, Xcel has proposed to regulators a pilot that would allow the utility to store energy in the future in electric school buses. In summer, when fewer school buses operate and electricity demand runs high, the buses could serve as a source of stored power, Eagles said.
The Connexus project
The largest electricity cooperative in Minnesota, Ramsey-based Connexus Energy serves 132,000 homes and businesses in parts of Anoka, Chisago, Hennepin, Isanti, Ramsey, Sherburne, and Washington counties. The utility’s customers partly drove the solar and storage project.
“Customers have told us they want us to add more renewables as long as we didn’t raise their rates,” Burandt said.
Utilities and business pay “demand charges” during times when electricity demand is higher, such as late afternoon and early evening, he said. Reducing that demand with stored energy could yield savings, minimally, or at least allow for more solar without any additional cost to ratepayers, he said.
Planning for the battery-storage project began in July 2016, and a year later the cooperative secured three sites before reducing the project to two. Connexus vetted several companies before selecting NextEra Energy to build the 15 megawatts of lithium iron phosphate battery storage and SoCore Energy, now ENGIE North America, for the 10 megawatts of solar.
The 36-acre Athens Township site around 27093 University Ave. NE holds 6 megawatts of solar produced by more than 27,000 solar panels, enough to power 1,245 homes. The 9 megawatts of storage at the same site consumes just 0.07 acres of land filled by rectangular containers housing 1,890 lithium iron phosphate batteries. The storage holds enough electricity to power 4,045 homes, he said.
The 18-acre Ramsey site south of Highway 169 at Llama Street Northwest and Riverdale Drive Northwest produces 3.4 megawatts with nearly 14,000 panels capable of generating enough electricity for 644 homes, said Burandt. The 6 megawatts of storage, held in 1,260 batteries, could supply 2,679 homes with electricity. Collectively, the sites could power nearly 1,900 homes with solar and store enough energy to take care of 6,700 houses.
Connexus does not own the battery storage but instead pays NextEra Energy “to store our electrons,” he said. The same is true of the solar panels, which developer ENGIE owns. It sells electricity to Connexus under a power-purchase agreement, a common arrangement in the solar industry.
The idea is simple. “The plan is to take [solar] production from the mid-day and shift it to reduce our peak,” Burandt said. He figures the solar-storage units will be used four to six times a month during peak demand.
Though the project has just begun, Connexus likes the idea of solar and storage together so much that it plans to ask for bids for a 5- to 7-megawatt project next year. Customers should be impressed. “We have been able to add renewable energy without raising rates,” Burandt said.
Anderson believes the project will open the door to more battery storage across the state and region.
“It’s huge in Minnesota, it’s really significant, because it’s by far the largest solar plus storage we have,” Anderson said. “People will learn from it what is possible here.”View All ENGIE in the News