The Federal Energy Regulatory Commission should order the Midcontinent grid operator to lift its ban on wind, solar and hybrid storage resources from selling ancillary services, according to a complaint from the Solar Energy Industries Association.
Allowing dispatchable intermittent resources to participate in the Midcontinent Independent System Operator’s ancillary services markets would provide new sources of revenue for generators, improve grid reliability and reduce system costs, SEIA said in the complaint filed Tuesday at FERC. Earthjustice filed it on behalf of the trade group.
“It is well-established that wind and solar resources can provide a wide variety of ancillary services – fast and accurate regulation up and down services among others – thereby increasing reliable market operations, lowering overall system costs and providing MISO more flexibility for emerging market conditions,” SEIA said.
MISO operates an ancillary services market for regulation service, spinning reserves and supplemental reserves that help maintain grid reliability. However, the grid operator across 15 states and Manitoba is the only regional transmission organization or independent system operator that doesn’t allow intermittent resources to provide ancillary services.
The complaint comes as wind, solar and hybrid resources are expected to grow across MISO’s footprint. The grid operator has 1,650 generator interconnection requests totaling 281 GW, with about 80% of the capacity coming from solar, wind and hybrid storage resources, according to a December MISO presentation. The rest of the queue includes 47 GW of stand-alone storage and 7 GW of gas-fired generation.
“Because of the changing resource mix, ancillary services once provided by conventional generators will now require alternate sources such as wind and solar,” SEIA said. “Lifting MISO’s prohibition would not only increase competition, but also open new resources to provide the critical grid stabilizing services that MISO will need for a stable and reliable grid.”
Not only can wind and solar provide ancillary services, they can often do it more accurately and more quickly than other resources, SEIA said, pointing to studies and Xcel Energy’s experience in Colorado.
MISO didn’t reply to requests for comment.
Its ancillary service market is “significant,” with the average price in 2021 being about $13.55/MWh for regulation reserves, $3.54/MWh for spinning reserves and $1.11/MWh for supplemental reserves, according to the complaint.
The issue of lifting MISO’s ban was raised in June 2018, but has languished in the grid operator’s stakeholder process, according to the complaint. MISO in December recommended the issue be removed from consideration.