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Enel Green Power España solar farm to be paired with 8.5MWh of iron flow batteries from ESS Inc

17 of ESS Inc’s Energy Warehouse systems will be connected at the site. ESS Inc said the deal follows a six month evaluation of its technology and the company itself by Enel Green Power. Image: ESS Inc.

An order for 8.5MWh of iron electrolyte flow battery energy storage systems (ESS) has been received by US manufacturer ESS Inc from Enel Green Power’s Spanish arm. 

Enel Green Power España will deploy the flow battery capacity — contained in 17 separate ESS Inc Energy Warehouse systems — at a solar PV power plant. Each Energy Warehouse comes with between 50kW and 90kW of peak power, between 400kWh to 600kWh of capacity and can be configured to provide between four and 12 hours of energy storage duration. 

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ESS Inc CEO Eric Dresselhuys said in a media release sent to that the deal comes after a six month assessment of the technology and his company to meet the customer’s requirements on cost, performance and durability. 

With ESS Inc now a qualified vendor to the renewable energy division of Italian power company Enel, the deal is part of an agreement to deploy the flow battery systems to support local power grid needs in other locations within the European Union, the US company said. 

ESS Inc did not provide specifics on the applications the battery systems will perform, but Enel Green Power’s head of long-duration storage and hybrid systems, Pasquale Salza, said that the Spain project will “assess and validate the ESS flow batteries”. 

The flow batteries were selected “due to their right combination of long-duration capacity, long-life performance, environmental sustainability and safe operation,” Salza said. 

“We are 100% committed to energy storage as an essential complement to our expanding portfolio of renewable energy projects.”

Only iron electrolyte technology company in a field of flow batteries

ESS Inc holds the patents for its all-iron electrolyte battery technology and is therefore currently the only provider, while other flow battery companies use different electrolyte chemistries — most commonly vanadium, although there are others trying to reach commercial scale using zinc-bromine and other liquid electrolyte materials. The iron flow battery is designed to have a 25-year lifetime, capable of more than 20,000 cycles, using a non-flammable, non-toxic chemistry.  

The company has counted the likes of Softbank energy subsidiary SB Energy as investors in its funding rounds.

The news comes just before a vote will be held on a planned special purpose acquisition company (SPAC) merger between ESS Inc and SPAC ACON S2 Acquisition Corp. ACON S2’s shareholders will vote on 5 October, with the deal valuing ESS Inc at US$1.2 billion. It is set to give the Oregon-headquartered manufacturer and technology provider a listing on the New York Stock Exchange (NYSE) in addition to unlocking funds to scale up its business. 

Also this week, ESS Inc said that its insurance cover deal with Munich RE, which enables 10-year cover for its Energy Warehouse range, has been expanded to include ESS Inc’s newer and larger Energy Center products. Cover includes a warranty backstop for the proprietary flow battery tech, as well as its electrolyte management system. 

Launched in February, Energy Center’s capacity starts at 3MW and up to 12 hours duration and discharge capability. A 1-acre Energy Center plant supports about 6MW / 90MWh of output and capacity, according to ESS Inc’s datasheet.  

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