What’s Current? Issue #21 – Battery Innovations for EVs and for the Grid

If there is anything that unites Californians it is a belief that anything is possible. How else to explain our state’s mad rush into renewables. Even a skeptic ought to be impressed. With massive wealth, a diverse and resilient economy, abundant sunshine and mild winters, and infinite reserves of imagination that define our culture, the question isn’t whether or not California can transform its energy economy. The only question is how much we’re going to spend doing it, and how many dead ends and mid-course corrections we’re going to experience along the way.

This week, we explore the potential of batteries to store and buffer intermittent sources of energy. Notwithstanding the vital debate that must continue over which intermittent renewables are truly sustainable, let’s assume that California will transition a significant share of its electricity generation to renewables. What’s the role of batteries?

The reality and origin of a hollow phrase: ‘energy transition’

First a cautionary note. This recent article by the Manhattan Institute’s incomparable Mark Mills reminds us that batteries, along with most renewables, require a lot of raw materials. A lot of raw materials. He writes, “Because of unavoidable, underlying physics, fabricating wind, solar and battery hardware entails a radical increase in the use of a range of minerals from copper and nickel to aluminum and graphite, and rare earths such as neodymium. The increases range from 700% to 4,000% more minerals per unit of energy production.” Mills then claims existing and planned mine capacity, depending on the mineral, falls short by between 50 and 90 percent of the amount needed to transition to renewables. He also points out the hypocrisy of “the Administration’s canceling of domestic mining permits and launching multi-front regulatory rule changes that will make U.S. mining more difficult and more expensive.”

The potential of vehicle-to-grid power

Could batteries on board electric vehicles be used to buffer intermittent power? They could charge from the grid during the daily surge of photovoltaic supply, but fully charged vehicles could then supply power to the grid during peak demand. This technology is referred to as V2G (vehicle to grid) and is also being explored as V2B (vehicle to building) and V2V (vehicle to vehicle). Power your home during a blackout? Rescue and recharge a stranded EV in a remote location? All possible if EV batteries are upgraded with bidirectional function. But it’s not easy. The economics would have to be worked out to incentivize EV owners to send power back upstream. Charger units would require upgrades, and vastly decentralized grid management would become even more complex. Finally, participants would see their EV charge/discharge cycles increase, shortening the life of their battery.

California’s total vehicle miles traveled – average miles per kilowatt-hour

Despite challenges, there is tremendous upside to a fully realized V2G system. There are approximately 15 million registered vehicles in California, and the total vehicle miles traveled by Californians each year are estimated at 340 billion. At an average EV efficiency of 3 miles per kilowatt-hour, converting 100 percent of California’s automotive fleet to EVs would require an additional 12.9 gigawatt-years of electrical generation per year. California’s total electricity consumption in 2022 was 32.8 gigawatt-years, and of that, its in-state generation was 23.2 gigawatt-years, and the contribution from solar was 4.6 gigawatt-years. Here’s the upside: If every one of California’s 15 million automobiles was an EV that got 3 miles per kilowatt-hour with a 250 mile range, the combined fleet would have a storage capacity that boggles the mind, 1,250 gigawatt-hours. If V2G technology were perfected and made standard, there would be no need for stationary battery farms, because a minute fraction of EV participation would achieve California’s 50 gigawatt target for electricity storage.

Solid-state batteries “game changer” for electric cars

Well, maybe. The point, however, is that battery technology continues to rapidly evolve. So-called solid state batteries may become the new standard. Proponents claim an energy density at least 50 percent greater than conventional lithium-ion batteries, the ability to recover a 90 percent charge in just 10 minutes, and longevity up to 5,000 cycles compared to lithium-ion batteries that degrade after 1,000 cycles. They also don’t have a liquid electrolyte, improving safety. Problems still arise with temperature fluctuations, exposure to water, the stability of the electrodes, and a very high cost to manufacture. Time will tell. But EVs that charge in 10 minutes, either from the grid, a home, or another EV, with a 400+ mile range, would attract an entire new segment of buyers.

We’re going to need a lot more grid storage. New iron batteries could help.

An argument for large stationary battery farms is they can deploy batteries with much lower energy densities that could never work in a mobile application. This means they can use battery technologies that cost less and use less resources. The “iron-flow” battery is an example of a low cost solution on the verge of commercialization that uses materials that are cheap, abundant, and nontoxic: iron, salt, and water. Because these batteries store the electrolyte in an external tank, the duration of the battery’s discharge is only limited by the size of the tank. Thus practical designs can deliver batteries that can produce uninterrupted power for 16 hours or more, compared to 4 to 6 hours with lithium-ion batteries. Like all new technologies, flow batteries still face challenges before they can be commercially competitive. And other new entrants, such as sodium-ion battery technology, also offer stationary storage options to compete with lithium-ion.

Renewable technologies have a long way to go. But those of us who support an all-of-the-above energy strategy should never assume that surprising advances in renewables aren’t on the way. Stopping the obvious missteps, such as offshore wind, and preserving the obvious practical options, such as natural gas and nuclear power, should be our priority. Certainty is the enemy. Adaptability is our friend. Someday fusion energy will upend the entire paradigm. Until then, be flexible.