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.
“It’s the 2030 to 2040 time frame where it’s a little bit more challenging and we don’t necessarily have the right solution identified just yet,” Chaset says. “Some would say maybe it’s pumped hydro. Those are huge investments. Yes, there’s technological innovation happening, but that’s mostly concrete and steel.”
Alternatives To Batteries
Are there options for energy storage other than lithium-ion batteries? Yes, several in fact. The Holy Grail of energy storage is not batteries that can store electricity for a few hours, days, even weeks. It is long-term storage solutions that can capture and hold electrical energy for months at a time.
It’s more than time-shifting, it’s season-shifting, so electricity from hydroelectric generators made in the spring when rivers and lakes are full or solar power generated in the bright days of summer can be used in the winter.
Vanadium flow batteries are a possibility. Concentrated solar is another. Compressed air is another area being tried, most recently at part of an energy storage facility in Utah. Then there are the gravity storage ideas — use excess electricity to lift heavy weights high in the air, then use them to power generators as they return to Earth later. Better batteries are something that teams of researchers are working on in laboratories around the world.
Don’t Make Perfect The Enemy Of Good
Nick Chaset recognizes the changes any of these alternative strategies could bring to energy markets but feels the focus should remain on what is possible today. “My view is, let’s not make that investment yet if we don’t have to,” Chaset said. “Let’s make the investments that we know we need right now — that’s really solar plus energy storage — and let the technological ecosystem evolve a bit more to see what the winners and losers are.”
“Frankly, it’s about making lots of small bets instead of one big bet, because that one big bet — yes, it could work for you, but oftentimes it might not, given the pace of technological change. Whereas [with] lots of smaller bets over time, you’re sort of riding the wave of technological improvement,” he adds.
His approach embraces uncertainty and it’s really the process that has gotten humanity this far. Establish a goal. Make a plan to achieve the goal, Work the plan and notice if it is effective. Modify the plan based on experience. Work the new plan. Modify it accordingly. Lather, rinse, repeat ad infinitum.
“We’re demonstrating that we CCAs are a significant part of that solution, at scale,” Chaset says. Little more than a year after the launch of East Bay Community Energy, it is on pace to exceed its state energy storage procurement mandate by a factor of four. That’s impressive. It is popular to bash California but look around to see if your state supports community choice aggregation. If not, perhaps it is appropriate to ask your local officials why not?
We are in a race to perfect renewable energy before the Earth turns into a cinder. We need credible, realistic solutions, not hare brained schemes like geoengineering the upper atmosphere to blot out the sun. One solution is to electrify everything — transportation, heating and cooling, agriculture — and use renewable energy to power it all. That will require effective long term energy storage systems.
Lithium-ion batteries may not be the perfect solution but they are the best option available at the moment. They are allowing utility companies to consider shutting thermal generating stations and not build new ones. That’s an epic win for the world and buying us time to get to what’s next.