Rameez Naam yesterday posted a blog titled "How Cheap Can Energy Storage Get? Pretty Darn Cheap". He goes ahead and does a comparative study on price trends and how they compare to other sectors. The focus is primarily on lithium ion battery technology, but he also looks at flow batteries and compressed air technology. One basic assumption he does, which can be disputed, is that there is no lower cost of the raw materials but they will continue to fall as the production goes up.
However, he does make a compelling case for getting the cost of lithium ion below US$0.20 / kWh cycled, but flow batteries should be able to easily get below US$0.10 / kWh cycled.
"New natural gas costs around 7 cents per kWh. As solar and wind steal hours from natural gas plants (because they’re cheaper when the sun is shining and the wind is blowing), natural gas plants will sit idle longer. As a result, the price of natural gas electricity will rise to perhaps 10 cents per kWh, as the up-front capital cost of natural gas plants is spread over fewer kWh's out.
To compete with that on a 24/7 basis, we need storage that costs no more than 5 or 6 cents per kWh, and ideally less.
In other words, we need to cut the price of energy storage by a factor of 5 or 6 from today’s prices.
We’ve already cut energy storage prices by a factor of 10 since the 1990s. And if current trends hold, the world is very much on path to achieving cheap enough storage to allow 24/7 clean energy, and doing so in the next 15-20 years."