Bill Gates-backed ESS — which makes giant batteries out of iron, salt and water — starts trading

Published

4 years ago

October 11, 2021

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An ESS Inc battery.

Photo courtesy ESS Inc

ESS is trying to solve a critical problem with renewable energy: How to store energy from wind and solar installations when the wind isn’t blowing and the sun isn’t shining.

The company’s proposed solution is a long-duration energy storage batteries made of iron, salt and water, which are much cheaper and more readily available than the elements used in batteries today, like lithium and cobalt. Its early momentum attracted $57 million in investments from powerful backers like Bill Gates and Softbank, CEO Eric Dresselhuys told CNBC.

On Monday, it hits another milestone, going public via SPAC to begin trading on the New York Stock Exchange on Monday under the ticker symbol GWH. It hopes to raise $308 million through the deal.

“There have been very few solutions for this long duration up until now, and it’s largely driven from the fact that we didn’t rely on energy storage as a major solution for hardening the system,” said Dresselhuys, who became the CEO of ESS this year after decades of energy and technology executive experience.

The company launched in the garage of co-founders Craig Evans and Julia Song in Portland, Ore., in 2011 (they’re a married couple, in addition to being business partners), then moved to the Portland State Business Accelerator before expanding to its current 200,000-square-foot headquarters.

The company is backed by Bill Gates’ clean energy investment firm Breakthrough Energy Ventures, SB Energy (a wholly owned subsidiary of SoftBank) and multinational chemical company BASF, among other investors. The SPAC comes through a reverse merger with ACON S2 Acquisition Corp., run out of private equity firm Acon Investments.

ESS has not recorded any revenue yet, according to financial filings dated Sept. 8, but Dresselhuys says it has shipped product to customers, including TerraSol Energies in Pennsylvania and Siemens-Gamesa in Denmark; investor documents claim several other unnamed utilities as customers also. Also, ESS has orders in the pipeline from SB Energy and Enel Green Power España.

The company lost $245.3 million in the first six months of 2021, but only $18.4 million were operating losses (the remainder was due to losses on reevaluations of warrant and derivative liabilities). Operating losses were $17.4 million for 2021, and it expects to record its first profit in 2023.

Iron, salt and water: Safe, readily available materials

The big breakthrough for ESS is a long-duration battery built from readily available materials, explained Carmichael Roberts, a co-chair of the investment committee at Breakthrough Energy Ventures In a battery, the electrolyte is the liquid medium that connects the two ends of a battery, the anode and the cathode.

“The flow battery is cheaper, safer and has better operational life than conventional lithium-ion storage,” Roberts said.

Making a battery out of iron, salt and water means “there’s no toxicity, the technology we build doesn’t start fires or doesn’t blow up in fire,” said Dresselhuys.

Also, ESS batteries do not have lithium or cobalt, two common elements in batteries that are being impacted by supply chain crunches.

“Both are in potentially short supply globally and none are produced in the U.S.,” said Jesse Jenkins, an assistant professor at Princeton University who specializes in the energy grid.

“Lithium is less of an issue in the long run, as long as we recycle lithium ion batteries, but there may be some short-run price increases as production ramps up to match battery demand for EVs,” Jenkins said.

“Cobalt is a bit trickier and has come under fire for some of the supply chain relying on quote unquote ‘artisanal mines’ in Africa, which employ forced labor, and child labor in some cases, with people digging out cobalt by hand and very, very harsh conditions,” Jenkins said.

Neither does ESS use vanadium, a chemical element used in some flow battery technology. While promising, Dresselhuys says it’s too expensive to be meaningful.

“It’s one thing to make something work, and that can be very difficult. But it has to work cost effectively to be viable as a system because of the scale we’re talking about,” he said.

How the battery works: ‘The elegance is the simplicity’

Visualize a sandwich, said ESS’s business development lead, Hugh McDermott. The ESS battery technology is a stack of carbon plates with salt water with iron flowing through each layer.

Iron comes out of the salt water solution and sticks to one side of the plates. When the polarity of the plates is changed, the iron dissolves back into the water solution.

From a battery management control system, the flow of the ions can be switched, thereby also switching the flow of electricity onto and off the grid.

ESS Inc’s iron flow battery “stack.”

Image courtesy ESS Inc.

The idea of a iron flow battery has been around since the 1970s, Dresselhuys said. But there were technical issues that scientists hadn’t solved.

For example, early iterations of the iron flow battery technology would work for a while, but the electrolyte fluid would become imbalanced, build up on the battery, and the battery would become ineffective over time. To fix this, ESS developed a proton pump, which Dresselhuys says “allows the system to keep itself in balance throughout all of those charges and discharges so that the electrolyte is entirely clean.”

Early research was funded in part by almost $3 million dollars in grant funding from the Department of Energy’s ARPA-E program, as well as individuals and local investment funds.

“The elegance is the simplicity,” said Rich Hossfeld, co-CEO at SB Energy and a board member at ESS. (SB Energy is not only an investor, but also a customer.)

But it took a lot of research and development to get a simple solution to work. ESS has been working on research and development for a decade. The proton pump was a really key breakthrough for the company, but one of many.

“There’s a very large intellectual property moat around the core technology and that will make it very difficult for other competitors to build a battery that is similar to ESS’ battery,” Hossfeld told CNBC.

An ESS Inc battery

Photo courtesy ESS Inc

Another long duration battery being developed by Form Energy also uses iron and also is backed by Breakthrough Energy Ventures. Form, however, is developing iron-air batteries, which uses different technology and aims to provide energy storage for multiple days.

ESS batteries can store energy for 4 to 12 hours, whereas the lithium batteries in cars are typically capped between two and four hours, Dresselhuys said.

To go above four hours of energy storage with lithium-ion batteries requires increasing the number of lithium-ion cells, Hossfeld told CNBC. ESS, on the other hand, can just add more water, iron and salt to a bigger tank of its stack-sandwiches.

“The way to think about ESS cost-wise is they are cost parity with lithium ion at four hours, and about half the cost above that, which we think creates a big advantage for them,” Hossfeld told CNBC.

Another key to the ESS iron-flow technology is its resilience.

“Capacity stays the same between year one and year 20,” Hossfeld said. Anyone who has a cellphone knows that is not the case for lithium-ion batteries. “You open it up, it comes out of the case, right now it will give you 10 hours. We all know it doesn’t give you 10 hours in a year, right?”

Energy centers are co-located with a wind or solar farm, allowing the batteries to charge up during the day when the sun is shining and then discharge in the late afternoon when there is typically a bump in energy demand.

SB Energy’s first installation of ESS Inc batteries in Davis, Calif. SB Energy is an investor in ESS and also a customer. These are batteries SB Energy purchased.

Photo courtesy SB Energy

Similarly with wind. “You can store four, eight, 10 hours of wind plants in the middle of the night and then discharge it during the day as needed,” Hossfeld told CNBC. “We look at ESS as a really good complement to that daily cycling between wind and solar.”

The Energy Warehouse, the only ESS product that exists so far, is the size of a shipping container, 40 feet long and 8 feet wide.

“That container holds 500 kilowatt hours of energy. That’s roughly the energy that you would need to power 20 to 30 homes, depending on where you are in the country,” McDermott told CNBC.

Four ESS Inc batteries

photo courtesy ESS Inc

ESS is also building a product called Energy Centers intended for utilities and independent power producers — for instance, businesses that own large solar farms who then sell that power to the grid.

For these kinds of larger customers, ESS will use similar battery technology, but the battery modules will be contained together in a building. Customer trials are expected to begin in 2022.

The big challenge: Getting an iron flow battery to scale

While iron-based batteries are a well-known technology, the big challenge has been getting them to scale.

“Iron based chemistries for flow batteries have a long and storied history, rightfully so because in theory they have some of the lowest theoretical costs possible. On paper these systems scale quite well,” explained Dan Steingart, Associate Professor of Chemical Metallurgy at Columbia University

But the reality has been quite different.

“We have not seen widespread adoption of this class of batteries and its cousins because of last-mile engineering challenges that have in the past added unacceptable capital and operating costs when compared to other available technologies,” Steingart told CNBC.

Flow batteries depend on pumps and membranes that are highly technical. “Think a kidney, writ very large, working 10,000 times harder than it has to, all the time,” he said. “It has been very difficult to have these, in practice, operate in a reliable manner without significant ancillary systems (that make the system more expensive upfront) or maintenance calls (which increase running costs).”‘

That said, Steingart notes the “sufficient capital” ESS has raised to validate its solutions to these challenges.

Also, ESS in September secured a 10-year battery warranty backed by the insurance giant Munich Re, which “is a strong signal of a positive outcome,” Steingart told CNBC.

Cost is another conern.

“The iron flow battery technology looks very promising as it is safe, environmentally friendly, uses non-toxic materials that can be sourced in the US, and doesn’t degrade over time and over multiple cycles,” Jan Pepper, the CEO of Peninsula Clean Energy, told CNBC.

Peninsula Clean Energy, a community energy buyer and the official power provider for San Mateo County in Calif., has not worked with ESS directly, but it’s trying to deliver cost-competitive 100% renewable energy on a 24/7 basis by 2025. Pepper knows that energy storage will help meet those goals.

“The current challenge with iron flow batteries is the cost,” Pepper said. “If companies like ESS can bring the cost down for their technology, then they and others will be able to make a meaningful impact in decarbonization efforts and help organizations like Peninsula Clean Energy meet our ambitious goals.”

As Steingart told CNBC, “A goal I use is in my lab for long duration energy storage: The battery has to cost about the same price as dog food per pound and last forever with little intervention.”

That said, if ESS can do what its investors think it can, “the successful execution of this chemistry would be a significant milestone for grid scale energy storage,” Steingart told CNBC.

Environment

America – it’s a party now! Plus: an electric Honda Ruckus and updated BMW

Published

4 hours ago

July 7, 2025

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America – it's a party now! Plus: an electric Honda Ruckus and updated BMW

Elon Musk isn’t happy about Trump passing the Big Beautiful Bill and killing off the $7,500 EV tax credit – but there’s a lot more bad news for Tesla baked into the BBB. We’ve got all that and more on today’s budget-busting episode of Quick Charge!

We also present ongoing coverage of the 2025 Electrek Formula Sun Grand Prix and dive into some two wheeled reports on the new electric Honda Ruckus e:Zoomer, the latest BMW electric two-wheeler, and more!

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Prefer listening to your podcasts? Audio-only versions of Quick Charge are now available on Apple Podcasts, Spotify, TuneIn, and our RSS feed for Overcast and other podcast players.

New episodes of Quick Charge are recorded, usually, Monday through Thursday (and sometimes Sunday). We’ll be posting bonus audio content from time to time as well, so be sure to follow and subscribe so you don’t miss a minute of Electrek’s high-voltage daily news.

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Drop us a line at tips@electrek.co. You can also rate us on Apple Podcasts and Spotify, or recommend us in Overcast to help more people discover the show.

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FERC: Solar + wind made up 96% of new US power generating capacity in first third of 2025

Published

5 hours ago

July 7, 2025

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FERC: Solar + wind made up 96% of new US power generating capacity in first third of 2025

Solar and wind accounted for almost 96% of new US electrical generating capacity added in the first third of 2025. In April, solar provided 87% of new capacity, making it the 20th consecutive month solar has taken the lead, according to data belatedly posted on July 1 by the Federal Energy Regulatory Commission (FERC) and reviewed by the SUN DAY Campaign.

Solar’s new generating capacity in April 2025 and YTD

In its latest monthly “Energy Infrastructure Update” report (with data through April 30, 2025), FERC says 50 “units” of solar totaling 2,284 megawatts (MW) were placed into service in April, accounting for 86.7% of all new generating capacity added during the month.

In addition, the 9,451 MW of solar added during the first four months of 2025 was 77.7% of the new generation placed into service.

Solar has now been the largest source of new generating capacity added each month for 20 consecutive months, from September 2023 to April 2025.

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Solar + wind were >95% of new capacity in 1st third of 2025

Between January and April 2025, new wind provided 2,183 MW of capacity additions, accounting for 18.0% of new additions in the first third.

In the same period, the combination of solar and wind was 95.7% of new capacity while natural gas (511 MW) provided just 4.2%; the remaining 0.1% came from oil (11 MW).

Solar + wind are >22% of US utility-scale generating capacity

The installed capacities of solar (11.0%) and wind (11.8%) are now each more than a tenth of the US total. Together, they make up almost one-fourth (22.8%) of the US’s total available installed utility-scale generating capacity.

Moreover, at least 25-30% of US solar capacity is in small-scale (e.g., rooftop) systems that are not reflected in FERC’s data. Including that additional solar capacity would bring the share provided by solar + wind to more than a quarter of the US total.

With the inclusion of hydropower (7.7%), biomass (1.1%), and geothermal (0.3%), renewables currently claim a 31.8% share of total US utility-scale generating capacity. If small-scale solar capacity is included, renewables are now about one-third of total US generating capacity.

Solar is on track to become No. 2 source of US generating capacity

FERC reports that net “high probability” additions of solar between May 2025 and April 2028 total 90,158 MW – an amount almost four times the forecast net “high probability” additions for wind (22,793 MW), the second-fastest growing resource. Notably, both three-year projections are higher than those provided just a month earlier.

FERC also foresees net growth for hydropower (596 MW) and geothermal (92 MW) but a decrease of 123 MW in biomass capacity.

Taken together, the net new “high probability” capacity additions by all renewable energy sources over the next three years – i.e., the bulk of the Trump administration’s remaining time in office – would total 113,516 MW.

FERC doesn’t include any nuclear capacity in its three-year forecast, while coal and oil are projected to contract by 24,373 MW and 1,915 MW, respectively. Natural gas capacity would expand by 5,730 MW.

Thus, adjusting for the different capacity factors of gas (59.7%), wind (34.3%), and utility-scale solar (23.4%), electricity generated by the projected new solar capacity to be added in the coming three years should be at least six times greater than that produced by the new natural gas capacity, while the electrical output by new wind capacity would be more than double that by gas.

If FERC’s current “high probability” additions materialize, by May 1, 2028, solar will account for one-sixth (16.6%) of US installed utility-scale generating capacity. Wind would provide an additional one-eighth (12.6%) of the total. That would make each greater than coal (12.2%) and substantially more than nuclear power or hydropower (7.3% and 7.2%, respectively).

In fact, assuming current growth rates continue, the installed capacity of utility-scale solar is likely to surpass that of either coal or wind within two years, placing solar in second place for installed generating capacity, behind only natural gas.

Renewables + small-scale solar may overtake natural gas within 3 years

The mix of all utility-scale (ie, >1 MW) renewables is now adding about two percentage points each year to its share of generating capacity. At that pace, by May 1, 2028, renewables would account for 37.7% of total available installed utility-scale generating capacity – rapidly approaching that of natural gas (40.1%). Solar and wind would constitute more than three-quarters of installed renewable energy capacity. If those trend lines continue, utility-scale renewable energy capacity should surpass that of natural gas in 2029 or sooner.

However, as noted, FERC’s data do not account for the capacity of small-scale solar systems. If that’s factored in, within three years, total US solar capacity could exceed 300 GW. In turn, the mix of all renewables would then be about 40% of total installed capacity while the share of natural gas would drop to about 38%.

Moreover, FERC reports that there may actually be as much as 224,426 MW of net new solar additions in the current three-year pipeline in addition to 69,530 MW of new wind, 9,072 MW of new hydropower, 202 MW of new geothermal, and 39 MW of new biomass. By contrast, net new natural gas capacity potentially in the three-year pipeline totals just 26,818 MW. Consequently, renewables’ share could be even greater by mid-spring 2028.

“The Trump Administration’s ‘Big, Beautiful Bill’ … poses a clear threat to solar and wind in the years to come,” noted the SUN DAY Campaign’s executive director, Ken Bossong. “Nonetheless, FERC’s latest data and forecasts suggest cleaner and lower-cost renewable energy sources may still dominate and surpass nuclear power, coal, and natural gas.”

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Environment

Tesla was forced to reimburse Full Self-Driving in arbitration after failing to deliver

Published

6 hours ago

July 7, 2025

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Tesla was forced to reimburse Full Self-Driving in arbitration after failing to deliver

Tesla has been forced to reimburse a customer’s Full Self-Driving package after an arbitrator determined that the automaker failed to deliver it.

Tesla has been promising its car owners that every vehicle it has built since 2016 has all the hardware capable of unsupervised self-driving.

The automaker has been selling a “Full Self-Driving” (FSD) package that is supposed to deliver this unsupervised self-driving capability through over-the-air software updates.

Almost a decade later, Tesla has yet to deliver on its promise, and its claim that the cars’ hardware is capable of self-driving has been proven wrong. Tesla had to update all cars with HW2 and 2.5 computers to HW3 computers.

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In January 2025, CEO Elon Musk finally admitted that HW3 also won’t be able to support self-driving and said that Tesla will have to upgrade the computers. 6 months later, Tesla has yet to communicate a plan for retrofits to owners.

Tesla is now attempting to deliver its promise of unsupervised self-driving on HW4 cars, which have been in production since 2023-2024, depending on the model. However, there are still significant doubts about this being possible, as the best available data indicate that Tesla only achieves about 500 miles between critical disengagements with the latest software on the hardware.

The situation is creating a significant liability for Tesla, which already needs to replace computers in millions of vehicles, and it may need to do so in millions more.

On the other hand, many customers are losing faith in Tesla’s ability to deliver on its promise and manage this computer retrofit situation. Some of them have been seeking to be reimbursed for their purchase of the Full Self-Driving package, which Tesla sold from $8,000 to $15,000.

A Tesla owner in Washington managed to get the automaker to reimburse the FSD package, but it wasn’t easy.

The 2021 Model Y was Marc Dobin and his wife’s third Tesla. Due to his wife’s declining mobility, Dobin was intrigued about the FSD package as a potential way to give her more independence. He wrote in a blog post:

But FSD was more than hype for us. The promise of a car that could drive my wife around gave us hope that she’d maintain independence as her motor skills declined. We paid an extra $10,000 for FSD.

Tesla’s FSD quickly disillusioned Dobin. First, he couldn’t even enable it due to Tesla restricting the Beta access through a “safety score” system, something he pointed out was never mentioned in the contract.

Furthermore, the feature required the supervision of a driver at all times, which was not what Tesla sold to customers.

Tesla doesn’t make it easy for customers in the US to seek a refund or to sue Tesla as it forces buyers to go through arbitration through its sales contract.

That didn’t deter Dobin, who happens to be a lawyer with years of experience in arbitration. It took almost a year, but Tesla and Dobin eventually found themselves in arbitration, and it didn’t go well for the automaker:

Almost a year after filing, the evidentiary hearing was held via Zoom. Tesla produced one witness: a Field Technical Specialist who admitted he hadn’t checked what equipment shipped with our car, hadn’t reviewed our driving logs, and didn’t know details about the FSD system installed on our car, if any. He hadn’t spoken to any sales rep we dealt with or reviewed the contract’s integration clause.

There were both a Tesla lawyer and an outside counsel representing Tesla at the hearing, but the witness was not equipped to answer questions.

Dobin wrote:

He was a service technician, not a lawyer or salesperson. But that’s who Tesla brought to the hearing. At the end, I genuinely felt bad for him because Tesla set him up to be a human punching bag—someone unprepared to answer key questions, forced to defend a system he clearly didn’t understand. While I was examining him, a Tesla in-house lawyer sat silently, while the company’s outside counsel tried to soften the blows of the witness’ testimony.

He focused on Tesla’s lack of disclosure regarding the safety score and the fact that the system does not meet the promises made to customers.

The arbitrator sided with Dobin and wrote:

The evidence is persuasive that the feature was not functional, operational, or otherwise available.”

Tesla was forced to reimburse the FSD package $10,000 plus taxes, and pay for the almost $8,000 in arbitration fees.

Since Tesla forces arbitration through its contracts, it is required to cover the cost.

Electrek’s Take

This is interesting. Tesla assigned two lawyers to this case in an attempt to avoid reimbursing $10,000, knowing it would have to cover the expensive arbitration fees – most likely losing tens of thousands of dollars in the process.

It makes no sense to me. Tesla should have a standing offer to reimburse FSD for anyone who requests it until it can actually deliver on its promise of unsupervised self-driving.

That’s the right thing to do, and the fact that Tesla would waste money trying to fight customers requesting a refund is really telling.

Tesla is simply not ready to do the right thing here, and it doesn’t bode well for the computer retrofits and all the other liabilities around Tesla FSD.

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