Michael Goldman, Eversource Energy
This series of articles explores both grid scale and behind-the-meter (BTM) grid optimization strategies and the implications for our customers. The first article in the series set the stage by providing the regulatory framework and outlining the delivery framework being implemented to enable 150 megawatts (MW) of both grid-scale and behind-the-meter demand assets over the next three years in Eversource’s Massachusetts service territory.
Battery storage is often described as the “killer app” for the grid due to its versatility and ability to provide multiple services. This second article describes how utilities can re-program that “killer app” of storage to reduce costs for customers and reduce emissions. Future articles in this series will explore the technology, processes, and customer facing aspects of successful distributed energy resource programs. The last article in this series will offer a glimpse of how behind-the-meter and front-of-the-meter assets come together in the grid of the future.
To help states meet bold climate targets while simultaneously providing value to customers, it is critical for utilities to consider both utility-scale and behind-the-meter (i.e. customer sited) storage. In Massachusetts, Eversource has already received approval for two utility-scale storage projects. The first project is located on Cape Cod: a 25-MW/38-MWh project that will provide increased reliability and resiliency for the Outer Cape communities of Provincetown, North Truro, Truro and Wellfleet. The second project is a 4.9-MW/20-MWh system located on the island of Martha’s Vineyard. This battery system will reduce greenhouse gas emissions created by diesel-fired generators during times of high energy demand. These projects will be beneficial for customers by lowering costs by avoiding traditional investments, increasing reliability, allowing for additional renewable generation, and reducing emissions by decreasing the need to run older expensive, dirty fossil fuel generation during peak times.
In addition to utility-scale storage, utilities should consider customer-sited storage as well. Future articles in this series will discuss the synergistic effects of coupling utility-sited storage with customer-sited storage. Eversource expects to help deploy over 20 MW of customer-owned and sited storage that can potentially enhance grid operations. Taking a holistic approach to analyzing storage and which type of technology is best suited for each customer allows for a more customized approach to storage. For instance, lithium ion batteries may be a good fit for certain facilities that see temporary spikes in energy use from air conditioning or process loads. However, thermal storage, such as ice storage or phase change material, may be a better solution for a customer with cold storage or a food processing facility.
Incentivizing customer-sited storage
A subsequent article in this series will go into much more detail on the pros and cons of various customer-sited storage program designs. Eversource decided that paying for verifiable load reductions, as opposed to an upfront incentive for equipment, was the optimal path forward. To give customers maximum flexibility, Eversource has rolled out two types of storage incentives – one based on a “daily” dispatch of storage on every non-holiday weekday during the cooling season and one based on a “targeted” dispatch, which will be called three to eight times per season. Eversource will pay a higher incentive for the daily dispatch, recognizing that customers may not be able to use their battery for other purposes, whereas the targeted approach pays a lower incentive but allows customers more flexibility to use the battery for other reasons. There is no strict requirement for a specific battery vendor, only that the battery can communicate with Eversource’s energy dispatch platform.
To drive maximum customer-sited storage program participation, the goal should be to engage with customers by providing a high degree of flexibility in how a customer can participate in a battery program while at the same time providing a range of eligible storage technologies that can be appropriately customized to each customer. In addition to customization, one key benefit of storage is that the dispatch of storage lowers a facility’s load while minimizing customer operational interference. This is different than other load management programs where a customer may be asked to change the set point on their thermostat or temporarily change processes. Minimizing operational interference is key to keeping customers engaged and preventing them from opting out of a load control program.
An initial use case for customer-sited batteries is to dispatch them during times of regional peaks in an effort to bring down costs and greenhouse gas emissions. This will be accomplished by aggregating all various customer-sited batteries into an energy dispatch platform so they can be dispatched in a unified and coordinated manner. In this way, we can truly harness customer facilitated grid enhancements to provide benefits for all customers.
Michael Goldman is a Manager on the Energy Efficiency team at Eversource Energy, the largest energy delivery company in New England. He is a frequent contributor to conferences and articles on distributed energy resources and their impact on the evolving grid.