Maine explores rate design changes to promote energy storage system deployment

　　The Maine Public Utilities Commission (PUC) recently asked the state's public utility companies to weigh the rate design to help the state achieve the goal of deploying more energy storage systems and electric vehicles.

　　The report released a few days ago is based on three bills passed during the Maine Legislative Session in 2021, one of which sets the goal of deploying a 400MW energy storage system by 2030. Another bill requires the state to explore alternative rate structures for electric vehicle (EV) charging stations.

　　Some clean energy organizations say that alternative rate structures, including time-of-use rates, may encourage more residential and commercial energy storage deployments. Phelps Turner, a senior attorney for the Maine Protection Law Foundation, said: "It is very forward-looking to use rate design to promote these policies while reducing consumer costs and ensuring that utility companies continue to receive some return on investment."

　　Maine Governor Janet Mills, D signed a legislation in 2019 that set a goal of reducing greenhouse gas emissions by 45% by 2030 and achieving carbon neutrality by 2045. A four-year plan issued by the Maine Climate Commission in December 2020 defines a strategy for decarbonizing transportation and buildings, encouraging the deployment of more clean energy.

　　The American Energy Storage Association, the Northeast Clean Energy Council and the Maine Renewable Energy Association wrote in their comments that the time-sharing rate will help residential customers "optimize based on price signals" and use solar power generation facilities and energy storage systems. This includes incentives for customers who deploy and use energy storage systems in power systems. These groups also recommend using time rates as the default option for commercial and industrial customers, incentivizing them to charge when demand and price are lowest, and discharge during peak power demand.

　　These groups pointed out that the more accurate the actual cost reflected by customer prices, the clearer the price signal for operating the energy storage system in the most beneficial way for the grid. Grid-side energy storage systems benefit the most from flexible rate design and demand fee exemption.

　　Similarly, by encouraging battery cars to avoid charging during peak power demand periods, but to shift the charging load to off-peak periods and lower cost periods, this may be important for the deployment of electric vehicles.

　　Hawaii's rate design reorganization in 2017 helped to encourage more customers to adopt solar power facilities. Connecticut in the summer required power distribution companies to impose income-neutral tariffs on energy storage projects instead of charging on-demand, while New York State recommends independent deployment of energy storage systems to waive demand costs. According to the Brattle Group’s estimates, approximately half of U.S. investors-owned utility companies have options.

　　The Maine Central Power Company provides electricity services to approximately 520,000 residential users, and the company has proposed a voluntary time-of-use plan. However, the company said that currently only about 5,000 customers have registered.

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