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The 100-hour battery is real — iron-air just took a huge step forward!

Dave Borlace doesn't just report on a battery; he reports on the moment a theoretical curiosity becomes a structural necessity for the global grid. While the headline promises a "100-Hour Battery," the real story is Borlace's assertion that the era of short-duration storage is ending, replaced by a desperate need for multi-day resilience that only iron-air technology can currently promise.

The Intermittency Crisis

Borlace opens by dismantling the assumption that renewable energy growth is linear or simple. He points out that while wind and solar have climbed an "exponential adoption curve," they have created a new, dangerous problem: the "dunkelflaute," or dark doldrums, where weather patterns stall for days. He notes that despite political noise, the data is undeniable: "China actually has more wind capacity than the next 18 countries combined. And since 2020, it's been adding more solar power each year than the rest of the world combined as well."

The 100-hour battery is real — iron-air just took a huge step forward!

This framing is crucial because it shifts the debate from "can we build enough solar panels?" to "can we survive the week when the sun doesn't shine?" Borlace argues that lithium-ion batteries, while fantastic, hit a hard economic wall after six to eight hours. He writes, "Long duration energy storage, anything from 50 to 150 hours, is no longer a nice to have. It's becoming a structural requirement for our increasingly renewables dominated grids." This is the piece's strongest insight: we are moving from a grid that needs a buffer to a grid that needs a reservoir.

Critics might note that Borlace glosses over the sheer physical footprint required for such massive storage, which could face local zoning resistance even if the economics work. However, his focus on the "structural requirement" correctly identifies that the grid operator's math has fundamentally changed.

The Chemistry of Rust

The technology itself is described with a refreshing lack of mystique. Borlace explains that Form Energy's breakthrough is not a new element, but a new application of the most common metal on Earth. He describes the process as "reversible rusting," where iron pellets react with air in a water-based electrolyte to generate electricity. "The two main ingredients are basically nothing more sophisticated than good old iron and fresh air. Both are extremely abundant. Both are easily accessible and importantly both are cheap."

This simplicity is the technology's greatest asset and its most difficult hurdle. The battery discharges over 100 hours, making it useless for a smartphone but perfect for a city. Borlace acknowledges the trade-off bluntly: "So it's slow and heavy and completely unsuitable for mobile applications. But for fixed grid storage, it has enormous potential." The elegance lies in the fact that the battery can be shipped dry, with the water-based electrolyte added on-site by local suppliers, a logistical feat that "vastly reduces shipping and handling costs."

Unlike many other optimistic tech startups in recent years, Form has successfully crossed the dreaded valley of death that kills off roughly 90% of energy tech newcomers.

From Lab to Rust Belt

The most significant shift Borlace highlights is the transition from concept to commercial reality. He details how Form Energy, despite facing the usual "supply chain bottlenecks" and "labor shortages," has opened a factory in Weirton, West Virginia, on the site of a former steel mill. The company has already shipped its first major unit to Great River Energy in Minnesota. Borlace emphasizes the momentum: "Form Energy is now fully up and running with manufacturing and has just shipped to its first major customer."

The evidence of traction is compelling. With contracts signed through 2028 from major utilities like Georgia Power and Dominion, the company has moved past the "valley of death." Borlace notes that if they hit their target price of "$20 per kilowatt hour at system level, then iron air represents one of the cheapest forms of long-duration storage ever devised." This price point is the holy grail of the industry, potentially making long-duration storage cheaper than the fuel it replaces.

However, a counterargument worth considering is the timeline risk. While Form has a backlog, the global rollout of similar projects in Europe and India is still in early stages. The "2030 timeline" for European production, as Borlace mentions regarding Ore Energy, suggests that while the US lead is real, the global supply chain is not yet mature. The reliance on specific government incentives, which Borlace admits might be volatile, also introduces political risk to the economic model.

Bottom Line

Borlace's coverage succeeds because it moves beyond the hype of "new tech" to the hard reality of grid physics. The strongest part of the argument is the demonstration that iron-air is no longer a science project but a deployed asset with a multi-year order book. The biggest vulnerability remains the execution risk of scaling a novel manufacturing process while navigating a fragmented global supply chain. For the busy reader, the takeaway is clear: the 100-hour battery is not a promise for the future; it is a requirement for the present, and the first factories are already turning.

Sources

The 100-hour battery is real — iron-air just took a huge step forward!

by Dave Borlace · Just Have a Think · Watch video

Back in early 2022, we took a look at what was then one of the most intriguing new ideas in long duration energy storage. The iron air battery developed by a US company called Form Energy. It was a simple concept almost elegantly crude in a way based on nothing more exotic than iron, water, and air. The idea promised days of energy storage at a fraction of the cost of lithium ion using materials so abundant they made lithium look like rocking horse doodoo.

Then in early 2023, we took another look to see what progress had been made. And it was promising, but pretty limited. Now, those two videos got a lot of attention, but they also prompted plenty of you to leave comments like, "Sounds great, Dave, but will it actually happen?" We're almost 3 years down the line now from that last video. So, I thought it might be time to have a look at what's been built, what hasn't, what's working, and what's still to come in what I reckon is a fascinating little niche of the clean tech landscape that has the potential to become a very big player indeed.

Hello and welcome to Just Have a Think. So, let's start with the problem that iron air energy storage is trying to solve then. And to be blunt, it's intermittency. Unless you've been living in a cave for the last few years, you can't fail to have noticed that wind and solar power have been climbing relentlessly upwards along an exponential adoption curve.

According to the energy think tank Ember, in 2024, while hydro, nuclear, and other clean energies remain flat or falling, growth in wind and solar pushed all clean energies upwards to more than 40% of total global electricity generation. despite the misguided ramblings of the US president during his recent speech at the World Economic Forum. >> China makes almost all of the windmills and yet I haven't been able to find any wind farms in China. Did you ever think of that?

>> China actually has more wind capacity than the next 18 countries combined. And since 2020, it's been adding more solar power each year than the rest of the world combined as well, reaching its overall 2030 renewables capacity target 6 years early in 2024. I could keep going with record-breaking stats from other regions like India, Pakistan, ...