The growth in energy storage is rapidly evolving the power industry and the Southwest Power Pool is the latest entity grappling with how to integrate the new resource.
Richard Dillon, SPP market policy technical director, discussed the findings of the grid operator's Electric Storage Resources white paper at the Markets and Operations Policy Committee meeting Wednesday morning.
"It's flexible in a lot of ways. It allows us to time shift energy," Dillon said of energy storage resource technology.
Energy storage can serve as a substitute for transmission by resolving short-term reliability issues such as voltage support and congestion, which could avoid costly transmission upgrades, according to the SPP white paper.
It can also serve as a substitute for generation resources, and it can do all this simultaneously, Dillon said.
However, Dillon said it could also be too much of a good thing since energy storage responds so fast that the rest of the system can't keep up, as other regions have experienced.
As the cost to build energy storage resources has decreased and recent tax law changes are more favorable to energy storage resources, there has been a significant increase in interconnect requests to the transmission grid, leaving SPP to figure out the best way to tackle this situation.
"We have a great asset coming into our region and we don't want to limit it," Dillon said.
There were less than 1 GW of electric storage resources in the SPP generation interconnection queue in late 2017. By mid-2019, that number had jumped to nearly 7 GW with expectations to come online in two years, Dillon said.
"It has been accelerating every time we turn around," Dillon said of energy storage resource interconnection requests.
Current SPP open access transmission tariff and business practices do not address some of the unique aspects of energy storage resources, so SPP has a number of initiatives underway to address the integration. However, there remain unanswered questions.
"We all need some sense of what's the urgency of dealing with these issues," one member said regarding feedback on the issues raised in the white paper, such as transmission planning, cost-recovery policies, and modeling and controlling hybrid configurations.
Hybrid resources should be a priority, another member said.
"I think we'll see more and more storage deployed with existing resources," he added.
Markets and Operations Policy Committee members discussed the pros and cons of forming a task force or a steering committee to prioritize issues and facilitate workload, versus putting the workload on the Strategic Planning Committee.
"We don't need the answer today," Dillon said, but rather need to look at what the priority is when it comes to energy storage technology within SPP.