sonnen, a leader in smart energy storage and virtual power plant (VPP) technology and ES Solar, a solar and energy storage contractor, have announced initial results following the launch of their “Go Back” program, a new VPP business model enabled by Rocky Mountain Power (RMP), targeting existing residential solar customers.
The program allows Utah homeowners with existing solar installations to upgrade their system to include a grid interactive smart sonnen battery designed to harness solar and harmonize it with greater grid operation. Key benefits for customers include a substantially higher upfront Wattsmart Battery incentive from RMP, an annual bill credit for grid services, proactive backup power, lower CO2 emissions, and dependability.
ES Solar has already sold 18 MWh of sonnen retrofit energy storage systems via the Go Back initiative within the greater Wattsmart Program in Utah. The company estimates that more than 75% of its 2024 sales are via the Go Back program, resulting in 200-500 sonnen battery installations in Utah each month. This represents unprecedented growth for a specific use case that has rarely been focused on by major solar contractors.
RMP enables ES Solar and other solar contractors interested in selling the Wattsmart Go Back program with the opportunity to sell a superior upfront incentive due to the enhanced value that “firming” existing solar has to the energy system. This approach demonstrates a sharp contrast to the standard “new solar new battery” Wattsmart business model.
RMP is a national leader in the field of authentic battery VPP implementation. RMP is also the only vertically integrated utility in the U.S. that has directly integrated their specialized behind-the-meter battery VPP into their grid operating system, without a distributed energy resources management system (DERMS) solution in the middle, while dispatching the battery fleet every day, deploying up to eight genuine grid services that are focused on electrochemical energy storage technology.
RMP’s Wattsmart VPP is a fully scalable program that is service territory wide and is therefore not a pilot. The RMP Wattsmart Distributed Battery Grid Management System (DBGMS) VPP has now grown to over 40MWh of energy capacity, a substantial portion of which was sold by ES Solar.
RMP customers who have installed solar prior to September 1, 2021 may qualify for an upfront incentive of $600/kW on their battery system by enrolling in Wattsmart. Comparatively, Wattsmart customers installing both new solar and a new battery may qualify for $400/kW.
“Existing solar customers are very interested in adding an intelligent energy storage system to their solar array, not just for backup power, but for the other benefits that a storage system can provide,” said Zach Randall, VP of sales at ES Solar.
In addition to their Go Back business, ES Solar is experiencing a 95% battery attachment rate for new solar sales, with over 90% of these customers enrolling in the Wattsmart VPP. Following installation, these batteries are dispatched daily to carefully sculpt and flex PV generation and load to meet the needs of the grid.
Currently, Rocky Mountain Power has approximately 80,000 solar customers across its service territory that do not have smart grid interactive batteries. ES Solar’s approach to targeting Go Back customers includes a world class marketing engine that is uniquely customized to the VPP and Go Back initiative. Over the next five years, ES Solar’s objective is to use this approach and firm 40% of all residential solar arrays in Utah with retrofit sonnen VPP batteries, an estimated 32,000 homes. This will create a first-of-its-kind in the U.S. market transformation that converts a rooftop solar fleet from intermittent generation to a firm dispatchable grid asset.
“Through their Wattsmart Go Back expansion, ES Solar has established a new, replicable business model and sales marketing strategy designed to inspire the revolution away from solar alone and into grid-interactive and responsive solar that supports, rather than becomes a nuisance to, society’s energy grid,” said Blake Richetta, chairman and CEO of sonnen USA. “ES Solar’s work in the RMP service area to date is an ideal case study which illustrates the potential national impact and scalability of a grid harmonizing, as opposed to grid defecting business model. Using batteries to firm existing solar and enable the implementation of flexible DER systems and VPPs is the key to supporting genuine energy transition for humanity.”
ES Solar believes their VPP focused business model is one that can be scaled and applied in other markets, such as California, where smart grid interactive batteries have the capability to firm solar and support a reliable and sustainable grid infrastructure alongside California’s Net Billing Tariff (NBT). At its current growth rate, ES Solar’s VPP business model innovations are likely to expand into regions across the U.S. over the coming years.
