Tech companies like Apple, Facebook, and Google are spearheading the switch to renewable power in the commercial world. Not to be outdone, Amazon announced last month it is adding PV systems to three of its fulfillment centers in the UK, according to Solar Power Portal.

3 MW of power were going to be added to the company’s existing facilities in Rugeley and Daventry as well as its newest location at Doncaster. Now comes word that Amazon’s fulfillment center in Tilbury will add 4.074 MW of rooftop PV to the small solar system already there. The new installation will be composed of 15,000 solar panels (270 watt each) manufactured by Jinko Solar. But unlike the new systems at Rugeley, Daventry, and Doncaster, the installation at Tilbury will include a 3.77 MW Tesla battery made up of 28 Tesla Powerpack storage units. The system is being planned and installed by Push Energy.

The Tilbury building consumes about 20 GWh of electricity every year. Rated at 3.5 GWh, the new rooftop system will meet just under 18% of that annual total. All of the electricity from the solar panels will be consumed onsite. According to filings with local authorities reviewed by Solar Power Portal, the Tesla Powerpack batteries will be charged from the local grid and will primarily be used to decrease grid connection stress during periods of peak demand.

The Tilbury system will use 82 Huawei inverters as part of the installation. Asked if the company plans to add battery storage to any of its other locations in the UK, an Amazon spokesperson declined to comment.

While battery storage is still in its infancy, experience at the Hornsdale Power Reserve in South Australia indicates such battery facilities can generate income for their owners by charging when the cost of electricity is low and selling it back to the grid in times of peak demand when energy prices are higher. The Hornsdale battery has already saved the local utility grid almost $9 million in its first 6 months of operation thanks to such energy arbitrage strategies.

With savings like that possible, it is little wonder that more large energy consumers are considering adding battery storage to their solar power installations.