Clean energy journalism for a cooler tomorrow

Energy Vault pivots, Ford tantalizes, and more energy storage news

Dispatches from the first solar-storage expo in years.
By Julian Spector

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A rendering of the Energy Vault Resiliency Center with solar generation at a decommissioned coal plant location (Energy Vault)

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2022 is off to a busy start.

Last week I made my first appearance on our Carbon Copy podcast, discussing my reporting trip to Hawaii and the race against time to switch from coal power to clean energy on Oahu. (Listen and subscribe!) For more on Hawaii’s high-stakes energy transition, read my feature article on how success will involve individual households and big clean-power plants working together. You can also watch our video to see a soon-to-be-retired coal pile and its replacements up close, and to catch up with the rest of our Hawaii coverage.

Also last week, your humble correspondent ventured out to the biggest clean energy industry expo since the beginning of pandemic times: the combined Intersolar North America/​Energy Storage North America gathering in Long Beach, California.

I’m vaccinated, I’m boosted, and I’ve got a stack of luscious Canary Media business cards that the world deserves to see, so I went for it. Loudspeakers repeatedly interrupted panel discussions to proclaim that masks were required inside the building, but that didn’t dampen the enthusiasm among the attendees — a workforce that paradoxically experienced propulsive growth in the time that much of the economy was put on hold.

Here are the vignettes that stood out as I stumbled around the expo hall, glasses fogged but heart full.

Crane drain

Remember Energy Vault, the energy-storage startup that’s riding to public markets and a potential billion-dollar market cap with its giant block-stacking technology?

The world is still waiting to see Energy Vault build a commercial project for a customer, as it originally promised to do in 2019. But the startup has successfully deployed several artists’ renderings, and I caught a glimpse of its latest at the expo.

A rendering of the EVx platform (Energy Vault)

Energy’s Vault’s premise is to use clean electricity to stack multiton blocks and then discharge electricity by rapidly lowering them. Previously, the company promised to keep costs low and reduce technology risk by buying its cranes from established crane companies. The startup would tweak the traditional design to include six arms and use machine-vision technology for grabbing and manipulating the bricks. But it wouldn’t need to reinvent the wheel by designing its own structure to hoist heavy blocks many stories into the air.

Looks like we’ve got ourselves a pivot.

The new renderings dispense with anything recognizable as a crane; instead, they feature what looks like a giant metal honeycomb. Elevator contraptions running along the perimeter lift 30-ton monoliths up high, and then they get shuttled horizontally into the interior of the building to store their potential energy. It almost looks like a three-dimensional game of Tetris.

This does seem more structurally secure than a freestanding tower of bricks. If the ground wobbles, there’s a robust lattice of beams and columns holding things in place.

The obvious downside is the difficult-to-fathom quantities of steel this must require. It’ll also need a nice, firm foundation to rest upon, portending additional tonnage of construction materials.

Perhaps the new design is a clever countercyclical bet on commodities markets; right now, at least, constraints on even basic building materials are driving up costs for clean-energy plants.

It can be hard to vet claims about cost-competitiveness in long-duration storage because most of it exists in a purely hypothetical state. Energy Vault says it will be cost-competitive at 12 hours of storage duration. But it also claims to be economically viable” for two to four hours, which is squarely in the sweet spot for lithium-ion batteries. That means that all the hefty construction efforts and engineering required for the gravity-based system are supposed to end up being cheaper than the mass-produced batteries with mature supply chains and years of vetting in the field.

Most energy-storage entrepreneurs are doing all they can to drive down the embodied material cost of their products — by reducing need for rare-earth metals or by designing around cheap materials or readily available industrial machinery. With its latest reinvention, Energy Vault is going maximalist instead.

Time for Ford to quote numbers on home backup power

Ford has staked out a bullish position on how electric pickup trucks will do things their gas-burning forebears never could (much more than rival GM chose to do, as I wrote about last week). One of those abilities is powering a household through an outage by drawing electricity out of the vehicle and into the home.

Of course, it won’t be as easy as just plugging something in. Ford was pretty coy with the details in its F-150 Lightning product launch last summer. But a few days ago, Ford’s charging installation partner Sunrun released more info ahead of the trucks actually hitting the market this spring.

To access backup power, customers will need the more powerful 80-amp Ford Charge Station Pro. The pro charger will be included with the higher-end extended-range Lightning models and available for purchase for the standard-range edition.

The setup will also require a vaguely named home integration system.” That contains a first-of-its-kind power converter” that allows electricity to flow in and out of the truck. And there will need to be a transfer switch that cuts off the home from the broader grid.

How much will this hardware and installation cost? Coming soon,” says Sunrun on the price info. That could be because a team of engineers is furiously hacking together the hardware ensemble as we speak.

The companies will need to share more details soon. Ford’s marketing promised relatively seamless vehicle-to-home connectivity. If that service adds a couple of thousand bucks to the truck price, that’s probably not going to dissuade people who are jazzed about the concept. If it somehow tacks on, say, $10,000, then backup power looks more like an expensive add-on than a perk of the truck’s design.

Experience from the home battery market suggests the auxiliary wiring to make this work will be more annoying, time-consuming and expensive than customers expect, at least at first. But this particular hardware has never been delivered to the masses. If anyone is positioned to streamline production and drive down costs through scale, it’s a brand like Ford.

Go short — and long

I moderated a panel at the expo on whether novel technologies for storing hours’ or even days’ worth of energy were finally hitting their stride.

I framed the conversation with a line from a review of the sector I wrote in 2019: Following long-duration storage is like rooting for a home team that’s always about to win next year.”

By the end of the hour talking with leaders from Malta, ESS and Form Energy, a straw poll showed that the audience had largely bought into the idea that the long-duration market is arriving now, not in the still-distant future.

A common critique of the long-duration sector is that a storage plant needs to charge and discharge to make money. If a plant holds enough power to run for a week straight (amid a prolonged cloudy spell or periods of slack wind, for instance), it has to make do with bringing electricity to market far less frequently than a battery that cycles every day. But the panelists marshaled counterarguments to this skepticism.

Hugh McDermott, who oversees global business development and sales at iron flow battery maker ESS, affirmed that his products need to cycle to make money. He argued that flow technology actually has a leg up on conventional lithium-ion batteries on that point because batteries incrementally degrade when they’re used, whereas flow systems purportedly do not. That means there’s less opportunity cost to running an ESS system than a typical battery.

Form Energy’s iron-air batteries are meant to run for days, so it’s more in the sights of the how do you make enough money” critique. Co-founder Marco Ferrara countered that just because the plant can run for days doesn’t mean it would exclusively behave that way. Instead, the plant could cycle on a daily basis, providing value to the grid in normal times, like a more conventional battery. But if a major demand event arises, like a heat wave or a deep freeze, the system will have lots more energy stocked up to deliver extended power when it’s especially valuable.

This adds nuance to the ongoing debate about why anyone should bother building long-duration storage when today’s markets only value much shorter durations. You can cobble together a business case by serving both roles.

Say hello to my little battery

A growing number of businesses want to go solar and add some batteries to further reduce their energy bills. But that desire can force tough trade-offs for commercial real estate.

Not every building has room to [install] a big storage system,” said Mitch Sargent, Western regional sales manager at startup Yotta Energy.

For those who want the benefits of storing clean energy without sacrificing space or aesthetics, Yotta makes miniature batteries that click in under rooftop solar panels. Each unit holds 1 kilowatt-hour, basically one-fourteenth the capacity of a Tesla Powerwall. But you can stick as many as you want on the solar racks.

(Yotta Energy)

That’s assuming the batteries don’t heat up on the sunny rooftop and burst into flames. To protect against that, Yotta starts with the more fire-resistant lithium ferrous phosphate chemistry, then wraps the batteries in a proprietary phase-change material that absorbs ambient heat and prevents it from affecting the battery cells. (Read more on the NASA-inspired tech in Jeff St. John’s profile of the company from last summer.)

After a couple of years demonstrating the technology, Yotta closed a $13 million Series A financing round in November and is shipping product this year. In fact, it’s sold out through the third quarter, Sargent noted.

Julian Spector is a senior reporter at Canary Media. He reports on batteries, long-duration energy storage, low-carbon hydrogen and clean energy breakthroughs around the world.