Ameren Missouri said its plans for three solar-plus-storage facilities across the state will improve customer reliability and allow for round-the-clock solar energy access.
The Ameren Corp. subsidiary on Sept. 3 told the Missouri Public Service Commission that it wants to build three 10-MW solar generating facilities, each with complementary battery storage ranging from 2 MW to 4 MW. If approved, the projects to be built at distribution substations in Green City, Richwoods and Utica, Mo., are to come online in 2020.
The company, known legally as Union Electric Co., asked the commission to grant certificates of convenience and necessity for the solar projects. Ameren Missouri did not ask for certificates for the battery storage aspects of the projects as they are not considered an "asset" under a rule outlining requirements for certificate applications.
Ameren Missouri said the projects would be the first-of-their-kind facilities in the state and among only a handful of solar-plus-storage facilities in the Midwest.
"These non-traditional solutions are expected to benefit customers by increasing reliability, growing the amount of renewable energy generation on the grid, and investing in the communities we call home," Ameren Missouri Chairman and President Michael Moehn said in a statement.
Ameren Missouri said on sunny days, customers near the proposed facilities will get energy primarily from the solar facility. The solar energy will also charge the battery. If there is a service interruption, each battery will be able to power connected homes for several hours, giving Ameren Missouri repair crews time to fix the service issue without causing an extended outage. Customers will also remain connected to the larger energy grid, the company said.
The roughly $68 million investment in the solar-plus-storage facilities is part of the company's "smart energy plan" a five-year, $6.3 billion investment plan that focuses on increased grid modernization and wind generation in Missouri. They are also a part of plans to add 100 MW of solar generation by 2027.
Tom Byrne, the company's senior director of regulatory affairs, told the commission the substations picked for the projects are located far from other Ameren Missouri facilities, served by a single feed radial subtransmission line, and have experienced reliability issues over the past several years. But because of the substations' remote locations, it is "uneconomic" to enhance their reliability by installing back-up subtransmission lines to the facilities.
"Solar generation facilities working in conjunction with battery storage can provide reliability improvements for these substations at a reasonable cost," Byrne said in testimony to the commission.
Ameren Missouri is looking at its system to determine if solar-plus-storage combinations can provide an economic reliability enhancement for other substations, Byrne said, and may in the future seek approval for similar projects.
Ameren Missouri asked the commission to make a final decision by Jan. 15, 2020. (Missouri PSC Case No. EA-2019-0371)
