Minnesota can economically get 70 percent of its electricity from renewable sources by 2050, as prices for wind, solar and battery storage continue to fall, a study has found.
The deployment of more solar and wind generation would be no more costly than new natural gas power, a cheap source of electricity, according to the study done for the state Department of Commerce. Enough solar generation could be added cost-effectively by 2030 to meet Minnesota's ambitious solar-power goals.
"We can achieve Minnesota's goal of 10 percent solar by 2030 with very competitive generation costs," said Josh Quinnell, senior research engineer for the Center for Energy and Environment, one of three groups that conducted the Solar Potential Analysis Report for the commerce department. "We found that at 70 percent renewable energy we are seeing costs that are comparable with natural gas generation."
The Center for Energy and Environment is a Twin Cities nonprofit group specializing in clean energy and energy efficiency. The study's other two lead contributors are the Minneapolis-based Great Plains Institute, a nonprofit energy research group, and Clean Power Research, a West Coast software company.
The study, to be released Thursday, was funded by the U.S. Department of Energy and was commissioned in response to a 2013 Minnesota law that set a goal of getting 10 percent of Minnesota's electricity from solar by 2030.
Minnesota is a leading state for wind power, getting at least 18 percent of its electricity from wind turbines, according to state and federal data. Solar power accounted for 1.2 percent of Minnesota's power generation at the end of 2017, up from almost nothing a few years ago.
Still, it's a great leap to get to 10 percent solar by 2030.
Solar-power capacity in Minnesota would have to be at 5 to 6 gigawatts, up from just under 1 gigawatt expected by 2018's end. A gigawatt is 1 billion watts. By comparison, Xcel Energy's two largest coal-fired generators in Becker, Minn. - which will be retired by 2026 - can produce 1.36 gigawatts.
Including hydropower, renewable energy accounted for 25 percent of electricity generation in Minnesota at the end of 2017. Nuclear power, which also is carbon free, made up 23 percent of Minnesota-generated power, while the rest came from fossil fuels, primarily coal.
According to the Solar Potential Analysis Report, Minnesota's grid in 2050 could reliably deliver power from a generation base of 30 percent fossil fuels and 70 percent renewables. The fossil-fuel plants smooth out power supply, since wind- and solar-energy production are inherently intermittent.
The deployment of battery storage, now a nascent technology in Minnesota, would also help the state get to 70 percent renewable power by 2050, according to the study. Batteries can inject energy into the grid when it's most needed, also smoothing out power supply. Batteries are increasingly being paired with solar panels nationally.
Solar and wind costs are expected to continue a long-term decline into the next decade, Quinnell said. "At our current projections, solar and wind are very cheap."
Even with the exclusion of federal tax subsidies, wind energy was the cheapest form of new power generation in Minnesota in 2017, edging out natural gas, according to a report earlier this year from Bloomberg New Energy Finance, a research group. Wind farms receive a 30 percent production tax credit, which phases out by 2020.
Solar farms get a 30 percent federal investment tax credit through 2019, which phases down to 10 percent over a few years. Tax-subsidized new solar projects cost 17 percent more per megawatt hour than unsubsidized wind power in 2017, according to Bloomberg New Energy Finance, which analyzed the cost to build and operate power plants. But solar power was still competitive with higher-cost new natural gas-fired generators.
Costs for new solar projects have fallen further this year. Technological advances and increasing economies of scale - as the solar and wind markets get bigger - have helped drive down costs.
"It really is possible to find an economical pathway to higher renewable generation," said Jeff Ressler, CEO of Clean Power Research.