US industrial conglomerate Honeywell has made an initial $27.5m investment in a developer pioneering iron flow battery energy storage systems.

Honeywell announced today (Monday) the strategic collaboration with US-based ESS Tech to advance the development of its patented iron flow battery design.

As well as its up-front investment, Honeywell has agreed to purchase $300m of ESS products that it can sell onto its customers, paying for $15m of that upfront.

ESS has meanwhile received an exclusive license of Honeywell IP related to flow batteries.

Speaking on a conference call today, ESS CEO Eric Dresselhuys said the collaboration will “open up any number of markets” for the company.

The “scale” at which Honeywell operates can help with things like deployment and supply chains, he said. “You just instantly drop into this global machine that has operations truly in every corner of the Earth.”

Bryan Glover, chief growth officer at the Honeywell Performance Materials and Technology group, said the “demand for long-duration energy storage represents a compelling market opportunity within the energy transition”.

The partnership with ESS can help decarbonise the commercial, industrial and utility sectors, he added.

Iron flow batteries circulate liquid electrolytes to charge and discharge electrons via a process called a redox reaction. Unlike in conventional batteries, ESS says it uses the same electrolyte on both the negative and positive sides of the equation.

ESS says this eliminates cross-contamination and degradation, meaning its batteries will last an expected 25 years, with conventional batteries typically lasting up to 10 years.

ESS also says its batteries are safer than the more commonly used lithium-ion batteries, which are prone to overheating and fires. ESS says this means its batteries reduce the need for fire safety equipment and other precautions.

In addition, ESS claims its battery is largely recyclable at end-of-life.

ESS recently reached an agreement to supply a 50MW/500MWh storage system to LEAG, one of Germany’s biggest energy groups, which is planning to build Europe's largest green hub in a vast lignite and coal area in southeastern Germany.

ESS has previously been backed by Bill Gates’ Breakthrough Energy Ventures among others.