Dive Brief:

• ViZn Energy Systems says it can pair a solar power plant with an energy storage system for 4ٔٔ¢/kWh.

• Pairing its 30 MW, 4 hour duration zinc-iron flow battery with a 100 MW solar plant can generate a 7% internal rate of return under a 4¢/kWh power purchase agreement, the Texas company says.

• ViZn says the returns are independent of potential revenues streams from ancillary service from the battery system.

Dive Insight:

Four cents per kWh could become the new target benchmark for combining energy storage to renewable energy resources.

Tucson Electric Power attracted a lot of attention when it signed a PPA for a solar-plus-storage system for 4.5¢/kWh. The project calls for a 100 MW solar system and a 30 MW, 120 MWh energy storage system, both developed by an affiliate of NextEra Energy.

In 2015, A utility in Hawaii made news when it signed a PPA contract for a solar-plus-storage system at $0.145/kWh. But TEP's PPA set a new benchmark for utilities looking to offset the intermittency of renewable energy with battery storage. 

But ViZn says it can beat that mark with its flow batteries because they have a longer life span than lithium-ion batteries.

ViZn says li-ion batteries last for only seven or 10 years and can usually cycle only once a day, while its zinc-iron flow battery, which generates power by exchanging electrolytic fluids, can last up to 20 years and can operate two, full-duty cycles per day.

ViZn says energy storage can now be added to a wind farm or solar plant at a lower price than new coal-fired generation based on 6¢/kWh cost from Bloomberg New Energy Finance. The company’s calculations assume that the storage system would be installed simultaneously with a solar farm because that is a requirement for receiving the federal investment tax credit.

"Nearly every utility daily demand curve in the world has a morning peak and a late afternoon peak and almost every solar and wind farm is financed for a 20-year economic lifetime. It is not hard to understand how a fade-free battery that delivers two cycles per day for 20 years is able to contract for output at record low energy storage system prices," Ron Van Dell, CEO of ViZn, said in a statement.

Correction: This article has been updated to reflect that the TEP storage facility is planned for 30 MW, 120 MWh, not 20 MW.