It’s pretty clear that renewable energy is more than price competitive with traditional energy sources such as coal, gas, and nuclear. Want proof? Look at the under 2 cents per kWh 25 year PPA the Los Angeles Department of Water and Power signed recently.
But we all know that the sun doesn’t always shine and the wind doesn’t always blow. To make matters worse, sometimes there is more renewable energy available than there is demand for electricity. To solve both issues, utilities and renewable energy providers are depending more and more on batteries that store excess electricity for later use.
Such time shifting strategies make renew able energy more dispatchable, meaning it is available when demand requires, regardless of whether the sun is out or a breeze is stirring, but they have their limits. Typical battery storage installations today can provide electricity for 2 to 4 hours at most. After that, it’s lights out, quite literally. So where do we go from here?
Community Choice Aggregation
Nick Chaset is the CEO of East Bay Community Energy, a community choice aggregate formed in 2018. Its mission is to buy cleaner power than utility PG&E can supply while keeping prices affordable and promoting well-paying jobs. According to Green Tech Media, CCAs have taken millions of customer accounts from California’s larger investor owned utilities.
Last week, Chaset signed an agreement with the city of Oakland to replace a jet fuel powered peaker plant near San Francisco Bay with a 20 megawatt, 80 megawatt-hour lithium-ion battery system. The question is, what happens in Oakland after the new battery is drained of power at the end of four hours?
Chaset has some thoughts on that question and shared them with Green Tech Media. “Right now, there’s still tremendous opportunity for the 4-hour [-duration] investments, which we’re going to continue to make,” at the contract signing in Oakland. “What you’ll see is, through 2030 probably, it’s storage, 4- and 6-hour batteries, [that] gets you where you need [to be].”
A Wood Mackenzie study of four existing natural gas-powered peaker plants found that a 6-hour battery could have handled 74% of the actual peak operations in 2017. The remaining events lasted too long for batteries to handle.
The upshot is that currently available battery technology can plausibly take over much of the peaker role, GTM says, but not the bulk power function served by larger combined-cycle gas plants. At some point, clean resources will need to supply larger amounts of power on demand for an extended period of time, especially in the evenings as solar generation tapers off.
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