Grid Storage set for prime time?

Its been a long while since I published anything renewable energy related – I had become burnt out by extravagant promises and the green bubble bursting in 2010. But things are starting to look up – solar leasing is a huge success, more and more projects are being built using renewable energy, and even thrifty casinos are getting in on the game.

So what happens when we start to scale up to even more renewable energy generation? The intermittent nature of renewables both in the immediate (sun goes behind a cloud) and daily dispatch (sun goes down at night) requires that there be some sort of grid stabilization and storage capacity.

A slide deck from EOS Energy Storage shows off their energy storage product – a 6MWh, 1MW capacity grid-scale battery storage system. The most impressive piece here isn’t the technology or scale, its the price they’re promising. Now I don’t know if that’s their off-the-line price when they start to ship in volume down the road, or the price they are debuting in 2014 when they start to ship their product for its first field deployment, but its a very compelling price for grid storage.

However I’m not entirely ready to jump on board yet, especially with the 2014 release date since they released a slide deck about a year earlier, where they said that they would ship product in 2013 (and they haven’t). They have acquired a customer since then, which is a promising sign.


Their quote price of $160/kWh and $1000/kW and promise of 10,000 cycles and 75% round-trip efficiency translates to a cost of 2.1 cents per kWh – which is more than the typical spread between off- and on-peak wholesale (spot market) prices along the west coast, which is around 1 to 1.5 cents per kWh. However, a net cost increase of half a cent per kWh to be able to include more renewable energy into the grid is a rather small price to pay. As solar and wind prices continue to decline, renewable energy will become more of a player, and storage and buffering of that power source will be needed. It wont take much storage – maybe 3-5% of total plant capacity (250MW solar would need 7.5MW of generation from battery storage) to smooth out bumps in the grid, and around 20% (50MW) to be able to store power for after-hours usage.

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