Energize Weekly, January 2, 2019
Minnesota can economically reach a mix of 70 percent wind and solar electric generation with storage by 2050, according to a U.S. Department of Energy-sponsored report.
The report done by Clean Power Research for MN Solar Pathways, a group of non-profit clean energy advocacy organizations and the Minnesota Department of Commerce.
Clean Power developed a modeling tool called the Solar Pathways Analysis (SPA) to test various scenarios. The analysis concluded that “expected cost decreases in solar, wind, and storage will enable Minnesota to achieve 70 percent solar and wind by 2050 at costs comparable to natural gas generation.”
The analysis also found that overbuilding wind solar generation and using a strategy of curtailing “is so cheap – that it makes more sense than gas and seasonal energy storage.”
With wind and solar generation costs a less than $20 a megawatt-hour (MWh), the study said that it would be economical to curtail these renewable resources—taking them off the grid—during periods of high generation but low load demand.
“The ability to curtail surplus renewable production removes the need to use energy storage to seasonally shift renewable energy production to serve load,” the report said.
The generating profile for 2050 would include solar capacity of 12 to 22 gigawatts (GW), 12 to 22 GW of wind and eight to nine GW of storage. The generation costs were calculated to be between $37 a MWh and $59 a MWh.
“This is noteworthy given the stringent production requirements used when modeling the 2050 results: solar, wind, and storage were modeled with a requirement to serve a constant fraction of Minnesota’s hourly load profile (for every hour of the year),” the report said.
Renewable sources made up 25 percent of Minnesota’s electricity generation at the end of 2017. Nuclear power provided another 23 percent.
The management of other flexible generating sources and flexible loads which can be shifted to optimal times could also contributed to reduced overall generating costs, the study said.
The strategic use of other generation during brief periods of low-solar and low-wind production could significantly reduce the storage, solar, and wind capacities needed to serve the hourly load. “As a result, the generation cost for 70 percent solar and wind was reduced by nearly half,” the report said.
Shifting the load from residential domestic hot water heaters and electric vehicles to different times would provide a 10 percent decrease in electric generation costs in 2025 and in 2050 they would provide a 20 percent cost reduction.
