- The Midcontinent ISO has 60 days to propose tariff revisions that can accommodate the participation of all electric storage resources, regardless of the technology, according to an order issued last week by federal regulators.
- The Federal Energy Regulatory Commission (FERC) did not fully side with Indianapolis Power & Light, however, stopping short of labeling MISO's tariffs discriminatory because they do not allow for storage installations providing primary frequency response.
- In November of last year, the commission issued a notice of proposed rulemaking to more effectively integrate electric storage resources into wholesale power markets.
Federal regulators continue to explore how electric storage can participate in wholesale markets, and have directed the Midcontinent ISO to file tariff changes. The commission denied IPL's petition on two of three points, also declining to find the grid operator's tariff unjust and unreasonable with respect to the current dispatch protocols for regulation service.
But FERC did say the tariff "unnecessarily restricts competition" by preventing storage from providing all the services that they are technically capable of providing. The order calls in the grid operator to explore the participation of all forms of storage, "regardless of the technology, in all MISO markets that they are technically capable of participating in, taking into account their unique physical and operational characteristics."
IPL filed its complaint in October, complaining the MISO tariff was unjust in how it treated storage, in particular
the utility's grid-scale lithium ion Harding Street Station Battery Energy Storage System. The 20 MW, 20 MWh project went into service in May, but the company has complained that while the batteries are valuable, there is no regulatory path for IPL to get paid.
You can read more of Utility Dive's coverage about the project, and how IPL is seeking to revise storage tariffs, here. The utility knew the grid rules were not favorable for battery storage back in 2009 when it began developing plans for the project, but it was hopeful that those issues would be addressed.
“We thought we would be able to tweak the regulations, but that didn’t happen,” Lin Franks, senior strategist for RTO, FERC and compliance Initiatives at IPL, told Utility Dive at the time.