By Amanda Durish Cook
CARMEL, Ind. — MISO last week said it now plans to have a market participation model for energy storage resources in place by early 2021, having filed a request for delay of FERC’s fourth-quarter compliance deadline.
MISO announced in April that it would seek at least another year to comply with FERC Order 841, saying the intricacy and expense of incorporating storage into its markets is greater than it originally expected. (See More Time Needed for Storage Compliance, MISO Says.) The RTO filed a request for an 18-month delay on May 1 in a 102-page filing that also responded to FERC’s questions on MISO’s initial proposal (ER19-465). (See More Info Needed on MISO Storage Participation Plan.) Vannoy said MISO’s filing focused more on providing explanation about the proposal instead of altering it.
Vannoy said when considering the “70-odd” requirements in FERC’s storage rule, some aspects of MISO’s plan make sense to RTO staff, but not third parties reviewing the proposal.
MISO now seeks an order on the storage participation plan by July. The RTO was originally beholden to a Dec. 3 go-live date for compliance with the storage order.
In the filing, MISO said the “complexity and expense” of its storage participation plan would negatively affect its ongoing effort to replace its aging market platform.
Vannoy said not receiving a FERC order on its proposal by April further backlogged “an already stressed schedule,” bogged down by the market platform replacement and a higher-than-expected cost to implement the storage plan with a third-party vendor.
MISO’s recent filing defined the phrase “very small” electric storage resources as those under 1 MW, answering one of FERC’s questions. The RTO has requested limiting participation of very small storage resources to 50 in the first year of compliance and 150 in the second year. FERC’s rule directed that all storage devices 100 kW and larger be allowed the opportunity to participate in RTO markets.
Vannoy said the limit on small storage devices is necessary to limit “administrative processes for the paperwork and modeling that can be somewhat burdensome.”
MISO also clarified that market participants will be responsible for maintaining their state of charge and updated an attached agreement on distribution-connected storage to clarify that storage owners will have to make metering arrangements.
At last month’s Informational Forum, CEO John Bear said MISO staff are currently studying energy storage case studies, including the Hornsdale Power Reserve in Australia, to determine how storage will fit into long-term planning.
Vannoy promised to return to the Market Subcommittee this summer to update stakeholders.