ES Solar, sonnen sell 18MWh of home batteries via Rocky Mountain Power initiative

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Energy storage virtual power plant (VPP) provider sonnen and contractor ES Solar have sold 18MWh of energy storage systems in Utah, US, as part of the ‘Go Back’ programme.

The programme, enabled by Rocky Mountain Power (RMP), allows Utah homeowners with current solar PV installations to add a grid-interactive smart sonnen battery. This smart battery is designed to optimise solar energy usage and integrate it with grid operations.

The provider confirmed that it had sold around 18MWh of sonnen retrofit energy storage systems via the initiative, which is part of the wider Wattsmart programme in Utah. The company also estimates that more than 75% of its 2024 sales are via the Go Back initiative, resulting in 200-500 sonnen battery installations in Utah each month. 

Wattsmart is a VPP aggregation programme run by RMP. It leverages energy stored at customer sites to help the energy supplier manage its grid network. The RMP Wattsmart Distributed Battery Grid Management System (DBGMS) VPP now has over 40MWh of energy capacity, with ES Solar selling a significant portion of it. This was confirmed in an Energy-Storage.news Premium interview with sonnen USA CEO Blake Richetta earlier this year.

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Wattsmart pays enrolled customers a per-kilowatt upfront fee based on the battery capacity made available for discharge into the grid. In addition, an annual bill credit is divided into 12 and paid out monthly.

It is worth noting that RMP has become one of the only utilities in the US to have directly integrated its specialised behind-the-meter battery VPP, not its grid operating system.

Zach Randall, vice-president of sales at ES Solar believes existing solar customers are adding an intelligent energy storage system to their solar array due to the multitude of benefits a storage system can provide.

“This pent-up demand simply needs to be tapped into by a highly dedicated, calculated, and passionate sales force, one that is more sophisticated than the average solar sales pitch,” Randall added.

“We have proven that this ‘higher level’ VPP sales pitch can indeed scale, as our sales organisation has grown since the launch of Wattsmart VPP from ≈ 20 people to over 300, as our overall organisation has grown from ≈ 40 to over 500.”

ES Solar stated that its VPP-focused business model can be scaled and applied in other markets, including California. California’s smart grid interactive batteries, alongside California’s Net Billing Tariff (NBT), have the capability to stabilise solar energy and support a reliable and sustainable grid infrastructure.

Sonnen is owned by oil and gas major Shell but reports emerged last year that the parent company was putting it up for sale.

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