Battery storage has long been one of the last remaining significant barriers to the widespread adoption of solar energy — and a nimbler, more resilient energy grid. But a number of players are quickly emerging with solutions.
In May, Tesla Energy dominated headlines when it unveiled a new home battery called the “Powerwall,” which can store solar energy and allow customers to cache grid electricity from non-peak periods to use during peak times. For business and utilities, there is a larger version available called the “Powerpack.”
The technology already is proving its viability. Jackson Family Wines— an early strategic collaborator in its development — uses 21 Tesla stationary storage systems at its Kendall-Jackson winery and others. The family-owned company expects to save approximately $2 million next year on electricity costs, reducing its electricity bill by nearly 40 percent.
Tesla claims its batteries will cost between $200 and $300 per kilowatt-hour, far less than the $500 average cost of lithium-ion batteries currently on the market.
Although the Powerwall and Powerpack initially will be made in Tesla's Fremont factory, the batteries eventually will be made in the $5 billion “Gigafactory” the company is constructing in Nevada. The massive factory could make or break Tesla’s success at achieving economy of scale for the batteries.
Tesla claims the factory will be able to produce lithium-ion batteries for about $175 per kilowatt hour by 2017.
But is building a mega-factory really the best way to drive down the cost of energy storage? A Cambridge, Massachusetts-based company called 24M Technologies doesn’t think so.
“Until now, there have really been only two ways to drive down the cost of energy storage — build massive and complex factories to produce lithium-ion batteries in high volumes or pursue entirely new chemistries that may never move from the lab to the commercial floor,” 24M spokesperson James Westhafer told Sustainable Brands. “We decided to work with the world’s preferred energy-storage chemistry and unlock new opportunities for cost reductions both through cell design and manufacturing innovations.”
24M claims to have reinvented the design of the lithium-ion cell, removing more than 80 percent of the inactive materials — which are expensive and contribute to the cost. This cell redesign means the company is able to make cells in a much simpler way — removing steps, equipment and the need for space to house all that equipment.
“The traditional method for making lithium-ion batteries takes days, is capital intensive and must run at high volume to achieve economies of scale,” Westhafer said. “We improve that with a 30 to 50 percent advantage in capital cost per annual kWh output of a factory and in the total capital outlay needed for a plant.”
The semisolid approach allows a modular plant design that reaches economies of scale for only $12 million — producing 80 MWh/year of battery — as opposed to a $1 billion plant, which needs to produce 1 GWh of battery to be economical. This means that a very different approach to scaling production can be practiced, 24M says. Rather than building giant plants such as Tesla’s Gigafactory, which are at the risk of markets not developing on schedule, 24M claims its approach allows production volume to be scaled in lock-step with demand.
“That’s a big manufacturing advantage,” Westhafer said.
There’s an added environmental benefit to 24M’s manufacturing process: By avoiding unnecessary layers of plastics and metals in the cell design, it is possible to easily and inexpensively recycle the battery components.
24M says that its breakthroughs in battery design and manufacturing techniques could bring costs down to $100 per kilowatt-hour by 2020. At that price, an electric car could more easily compete with a gasoline-powered one; laptops and cellphones could run for days on a single charge; and solar energy could become more economically viable than ever.