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The surprisingly strong case for Mill.

Food waste is a climate disaster, responsible for twice as many greenhouse gases as the global aviation, shipping, and paper industries combined. The food system generates about a third of our emissions, and nearly a third of the food it produces never makes it to our stomachs, which means we waste nearly a third of the farmland, fuel, fertilizer, electricity, irrigation water, and deforestation that goes into producing our food. At the same time, the 40 million tons of uneaten food that Americans send to landfills every year can decompose into heat-trapping methane, which also isn’t great.
But maybe Harry can help.
Harry is a sleek white Wi-Fi-connected garbage bin in my family’s pantry, a “food dehydrator” that transforms our kitchen scraps into chicken feed. It was created by Mill, a San Francisco-area startup that has raised more than $100 million to try to keep more household waste inside the food system. Mill’s founders built the Nest thermostat that limits household energy waste, so they know something about using high-tech hardware to try to adjust consumer habits in climate-friendly ways. They’ve shipped thousands of bins since April, and they say they’ve got more demand than their Mexican factory can supply.
Every day, my family tosses banana peels, pizza crusts, eggshells, moldy salmon, wilted celery, and other leftovers into Harry. Every night, Harry spends about six hours heating, grinding and shrinking them into nutrient-rich feed that looks like a cross between coffee grounds and dirt. Food waste is about 80 percent water, and Harry dries it out; it takes almost two months before the bin gets full and I have to mail the grounds back to Mill.
It’s a seamless user experience, with no smell, no schlep, and so far, virtually no noise. The bin has a cool wood-veneer lid with a convenient foot pedal to lift it; Mill CEO Matt Rogers helped engineer the iPod and iPhone at Apple before he started Nest, so he knows something about good design, too. And the company has calculated that its bins will help the average household avoid about half a ton of emissions every year, not even including the deforestation that won’t be needed to grow the chicken feed Mill will replace.
Mill’s app prompts you to name your bin upon arrival, and we named ours after Mill president Harry Tannenbaum, an engaging climate wonk who charmed me with his frequent use of the word “putrescence.” (I initially wanted to name it Wastoid, but my wife informed me that was stupid.) Tannenbaum got the idea for Mill after learning that food waste is the largest component of U.S. landfills.
“That freaked me out,” Tannebaum said. “Not only are we disconnecting those nutrients from returning to the earth by entombing them in landfills, they’re creating methane that cooks the earth. And it’s all starting in our kitchens.”
Composting can keep food waste out of landfills, too, but only 4 percent of U.S. households compost, because separating and storing food scraps can be a time-consuming, odor-producing, rodent-attracting hassle. And unlike many composting programs, which have absurdly complex requirements about what can be used, Mill’s bins can recycle just about everything except big bones, liquids, and excessive sugar. But their real bonus for the planet is that while compost can be used to help grow food, Mill’s grounds are still basically food. This summer, the Food and Drug Administration and the Association of American Feed Control Officials cleared the way for their use as commercial poultry feed, a much higher use than compost on the EPA’s food recovery hierarchy. It’s the first step in getting those grounds into the hands of chicken farmers.
It’s nice that my family no longer has to take out our regular trash so often, now that we no longer dump food into it, and I get a kick out of leaving Harry like this at night:
and seeing this the next morning:
It’s real bio-recycling, and while Mill would only be able to feed 7 percent of U.S. chickens if every U.S. household had a bin, every soybean that Mill can replace is a soybean that doesn’t need to be grown in the Amazon. And Harry helps us notice what we’re not eating — Instacart, you’re sending us too many mushy grapes — so that we can buy less of it and avoid waste on the front end.
That said, Mill is letting me use Harry for free, because I’m a dork who writes about food and climate change. I might be less enthusiastic if I were paying the hefty normal-human rate of $33 a month for the privilege of using its bins. Some composting services cost almost that much, and Mill emphasizes that its bins can take the stink and ick out of the kitchen experience — no putrescence! — but realistically, they provide more benefits for the climate than for consumers, which will limit the universe of consumers willing to shell out $396 a year for them.
Tannenbaum says Mill makes more economic sense in communities with “pay-as-you-throw” garbage collection, because Mill customers can save money by stepping down to smaller trash cans; in a pilot program in Tacoma, Washington, those savings have often reduced Mill’s effective cost to $8 a month. Mill is also working on deals with apartment buildings to provide bins to all their residents, so they could have easier trash management and less disgusting trash rooms. And corporations looking to shrink their carbon footprints could shrink their janitorial costs as well by putting Mill bins in their cafeterias. Tannenbaum points out that at Nest, after early-adopting consumers proved that smart thermostats could reduce energy waste, utilities helped defray the costs of moving Nest into the mainstream.
But change is hard, especially behavioral change. And change is slow, which is a problem, because the U.S. has set a goal of cutting food waste in half by 2030. There’s no way Mill can scale up fast enough to make a serious difference without government help. And that’s true for all kinds of food waste solutions — behavioral approaches like Britain’s “Love Food Not Waste” marketing campaign; policy reforms like tax breaks for restaurants that donate leftovers; and technologies like invisible biotech peels that prevent fruit and vegetables from spoiling. Our species is not going to wake up one day and make a collective decision to stop wasting a billion tons of food every year. We’ll need shoves (and cash) to overcome our inertia.
In fact, the U.S. Department of Agriculture announced last week that it’s investing $25 million in avoiding food waste. That’s a nice gesture, enough to fund 60,000 Mill bins for a year. But it’s a pittance compared to the $23 billion that USDA is spending on “climate-smart agriculture” — mostly regenerative farming experiments that, to put it charitably, will have an uncertain effect on emissions — and especially compared to the $428 billion in the last five-year farm bill.
Until recently, climate policy was seen as energy policy. But the world is starting to understand that unless it dramatically slashes emissions from the food system — at least a 75 percent reduction by 2050 — it won’t meet its climate goals even if it stops using fossil fuels. Congress is now talking about a new farm bill, and history suggests its main thrust will be to keep shoveling big money to big farmers. But it’s also an opportunity to make real investments in scaling up climate-friendly agricultural innovations like drought-tolerant super-trees, meat and dairy substitutes, alternative fertilizers, and food waste recycling options like Harry. Our energy and climate problems aren’t getting better fast enough, but our food and climate problems are still getting worse, and we’re not going to fix them by doing the same things we’ve always done.
That’s just putrescence.
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Just look at Heatmap’s latest poll results.
A few times a year, Heatmap News surveys a few thousand Americans on the biggest questions driving the world of energy, environment, and climate change. We’ve spent the past few days writing up the results of our latest poll, which was in the field in late May and which I thought was particularly striking.
It’s worth taking a step back to look at the biggest results together, because the American view of data centers is essentially in free fall:
The upshot of these findings: The public‘s turn against artificial intelligence and AI infrastructure is real, widespread, and cross-partisan. It doesn't matter whether Americans started out tolerating data centers or having no opinion about them; they now seem to resent them en masse.
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These results also suggest Americans see little distinction between data centers as energy users and data centers as the physical embodiment of AI and Big Tech. At Heatmap, we can be a wonky and energy-focused bunch, and so we tend to think about data centers primarily as large-scale electricity users. I think most approaches to come up with “data center policy” do the same. We know data centers are distinctive in some ways, of course — an AI data center might require more on-site batteries or power generation than, say, an EV factory — but fundamentally it is just another air polluter, large-scale power user, and light-industrial land user.
But the public does not see things this way. Americans understand data centers in the context of the much broader AI policy conversation about jobs, growth, alignment, and even human extinction. And so, I should add, do politicians: Senator Bernie Sanders has framed his data center moratorium proposal as a response to rapid AI development as much as anything having to do with energy affordability. For that reason, I wonder how long the distinction between these two policy conversations — data centers here, and AI policy over there — can persist.
One last thought on this topic: Is the public’s resentment starting to affect the AI boom overall? I think it might be. It was hard for me not to think of our polling results — or our analysis of canceled data center projects — as I read about a recent JPMorgan analysis that found America’s data center boom is “falling way behind schedule,” in the words of The Wall Street Journal. More than 60% of the data center capacity that is supposed to come online next year has yet to break ground, according to the bank; another 7% is “delayed.”
That’s partially due to equipment and labor shortages, but it also might be what a siting-and-permitting bottleneck would look like. Much like renewable developers or venture capitalists, data center developers work by picking a number of sites and trying to develop on all of them. If only a few sites work out, they’re still in the money. But if a falling share of projects are working out — if building anything, anywhere, is getting harder, everywhere — then it might materialize as delays.
Plus more of the week’s big money moves in critical minerals and electric vehicle charging.
Two of climate tech’s hottest sectors — fusion and critical minerals — dominated this week’s funding headlines. Helion led the pack with its $465 million Series G, helping to push the startup with the sector’s most aggressive commercialization timeline one step closer to putting power on the grid. The round follows last week’s news that German fusion startup Focused Energy secured a $240 million Series A, making it Europe’s most valuable fusion company.
Then there’s the critical minerals. Shortly after venture firm Gigascale Capital announced the close of its $250 million fund targeting the physical clean energy economy, it announced one of its first investments: Red Metals, a startup working to bring copper refining back to the U.S. Terra AI, which is using artificial intelligence to identify promising sites for mineral extraction, also landed fresh funding. Rounding out the week’s deals, EV charging and energy services company InCharge also raised a new round as it looks to expand into a broader suite of energy services.
Leading fusion startup Helion has nearly tripled its valuation with its latest $465 million Series G round, which aims to help the company deliver commercial fusion power this decade — the most ambitious timeline in the industry. Per the terms of the power purchase agreement Helion signed with Microsoft in 2023, the startup plans to turn on its first commercial reactor just two years from now. That’s far sooner than even its most precocious competitors, who aim to put fusion power on the grid by the 2030s at the earliest.
Joshua Kushner’s venture firm Thrive Capital led the round, which also included participation from new investors including Lux Capital and Alta Park Capital. Thrive now values the company at $15.5 billion.
“The investors that have joined this round, it’s institutional capital, some very marquee investors,” Helion’s CEO David Kirtley told me, explaining they were willing to back an unproven technology thanks to a series of recent milestones that Helion’s latest prototype reactor, Polaris, achieved. “Polaris earlier this year set records for temperature and fuel. We’ve also reduced a lot of the business risk on the regulatory front, the commercial front, and the actual supply chain, too.” In February, Polaris became the first reactor developed by a private fusion company to operate on deuterium-tritium fuel — the most common fuel in the industry — and to achieve a plasma temperature of 150 million degrees Celsius.
Helion differs from many of its peers pursuing more established reactor concepts such as tokamaks, stellarators, or laser-driven inertial confinement. Instead, Helion’s tech uses powerful magnets to collide and compress two fusion plasmas together, generating temperatures over 100 million degrees Celsius and triggering a fusion reaction. It then seeks to capture the electricity this reaction generates via electromagnetic induction — no steam turbine required — similar to the way regenerative braking works in an electric vehicle. If successful, the approach could enable smaller, more modular fusion reactors than conventional designs would.
While the company had originally aimed for Polaris to demonstrate electricity production from fusion in 2024, that date came and went with no new goal set. Kirtley told me that Helion remains on track to meet the terms of its agreement with Microsoft, however. The startup broke ground on its commercial reactor site last year in Malaga, Washington, where it already has access to a substation and grid interconnection from a dormant aluminum smelter. In addition to building out this facility, Helion also plans to use its new funding to boost production at its electrical component manufacturing plant in nearby Everett, which Kirtley said opened earlier this year.
As investors pour billions into artificial intelligence and the infrastructure supporting it, former Meta CTO Mike Schroepfer has raised an inaugural $250 million fund for his venture firm, Gigascale Capital, which is focused on the physical clean energy economy. This represents Gigascale’s first institutional fundraise since its founding in 2023; until now, the firm’s investments have come entirely out of Schroepfer’s own pocket.
The fund will target early-stage companies working in clean energy, grid infrastructure, critical minerals, and AI-enabled design and manufacturing, while reserving capital to continue backing its portfolio companies as they scale. Gigascale has already backed a number of big names in the space, including Commonwealth Fusion System, iron-air battery developer Form Energy, solid-state transformer company Heron Power, and clean baseload power startup Arbor Energy.
It’s also already begun investing out of this new fund, announcing this week that it led a $10 million seed round for critical minerals company Red Metals, which also included participation from JB Straubel, founder and CEO of the battery recycling company Redwood Materials. The company aims to help reshore copper refining in the U.S., and will use this fresh capital to support the development of a $70 million refining facility in Charleston, South Carolina. Red Metals says its process can convert copper scrap directly into a finished copper product, bypassing several of the costly and emissions-intensive intermediate steps typical of conventional refining.
The investment offers a window into the kinds of companies Schroepfer is most interested in — businesses that might lack the glamor of an AI startup but represent bipartisan opportunities to address core industrial bottlenecks. Copper, for example, is essential to all sorts of clean energy infrastructure, including transformers, power lines, and anode battery materials, but also critical for defense technologies such as radar systems and ammunition. Yet American copper production has been on the decline, with analysts projecting that the U.S. will face a refined copper shortage of over 2.5 million metric tons annually by 2035.
Sustainability-focused firm S2G Investments has been on a roll recently, announcing a $1 billion fund last month that aims to fill climate tech’s “missing middle” and backing Goshe Energy Storage with up to $40 million in strategic financing last week. Its latest move is leading a $46 million strategic investment round for InCharge Energy, an EV charging and distributed energy management company.
InCharge got its start installing and managing electric vehicle charging stations, and is now operating more than 30,000 assets across North America. Through its software platform and network of technicians, the company handles all monitoring, diagnostics, and on-the-ground repairs, taking on a charger’s full lifecycle to minimize downtime. With this new capital, InCharge plans to expand beyond EV charging and leverage its software and field service network in adjacent industries, including electrical infrastructure work such as panel upgrades and wiring repairs, as well as distributed energy resources like rooftop solar and battery storage systems.
“EV charging was the entry point, but our customers increasingly need help operating more complex energy infrastructure,” Rich Mohr, InCharge’s CEO said in a press release. “This investment from S2G accelerates our evolution into a full energy solutions provider and allows us to advance smarter technology and strengthen our service capabilities nationwide.”
It’s a hot week — nay a hot year, for critical minerals and subsurface exploration startups, especially for those pairing geology with artificial intelligence. AI-powered mineral exploration company KoBold Metals has raised about $1.2 billion to date, while geothermal exploration startup Zanskar has brought in about $220 million.
Now, another entrant is attracting investor attention. Terra AI has raised a $20 million Series A led by Khosla Ventures to help do it all — use AI to identify prospective sites for critical minerals mining, next-generation geothermal development, and permanent carbon sequestration.
Terra’s platform integrates vast geological and geophysical datasets to generate 3D subsurface models, as well as risk assessments that allow teams to evaluate a range of potential geologic scenarios. From there, the team can identify the best sites for exploratory drilling and thus reduce risk and uncertainty much sooner in the project’s lifecycle. The company even uses what it calls “geology reasoning agents” to help operators create their exploration plans, all with the goal of drastically reducing the notoriously long timeline between discovery and production, which can stretch to nearly two decades for many subsurface projects.
“Minerals sit at the center of every major technology and infrastructure transition, but today’s exploration results are not keeping pace with demand,” Terra’s CEO John Mern posted on LinkedIn. “Our mission is to advance the frontier of AI into the geosciences and help supply the metals and resources the next generation needs.”
One of the biggest fusion funding rounds of the year landed last week, and somehow much of the media — including me — missed it. German fusion startup Focused Energy raised a whopping $240 million Series A led by RWE, one of Germany’s largest energy companies. Yet unlike most deals of this magnitude, it arrived with little fanfare: No press release in my inbox nor a flood of headlines. So in the interest of making up for lost time, here are the details.
With this latest round, which also includes participation from the German Federal Agency for Breakthrough Innovation, the European Innovation Council Fund and Prime Movers Lab, Focused Energy has become Europe’s most valuable fusion company. Like several other leading players, including Inertia Enterprises and Pacific Fusion, Focused Energy relies on an approach known as inertial confinement fusion. This involves using powerful lasers to compress a tiny fuel target, creating the extreme pressures and temperatures required for a fusion reaction. To date, inertial confinement remains the only approach to have demonstrated net energy gain, with Lawrence Livermore National Lab achieving this milestone in 2022.
The startup plans to use this latest funding to build out a demonstration plant in the German state of Hesse, at a site where RWE formerly operated a nuclear fission plant. The company ultimately aims to build a commercial reactor by the mid-2030s.
Catching up with the American Council on Renewable Energy’s Ray Long.
Today’s chat is with Ray Long, CEO of the American Council on Renewable Energy. We first discussed the odds of permitting reform a year and a half ago, for one of the first Q&As in The Fight. Flash forward and we’re still in the same situation, but now also wrestling with added demand for electricity to power data centers. I wanted to talk again about whether he thought the rise of artificial intelligence would increase the odds of some federal deal happening any time soon. The result: a wide-reaching conversation about the future of the electric grid, the struggles to win community buy-in and the sclerotic nature of the U.S. Congress.
The following conversation was lightly edited for clarity.
Do you think the buildout of our energy grid is entwined with the rise of the nation’s data center buildout?
When you look at what we need over the next four years — 166 gigawatts, 15 times the peak load of New York City — that’s a lot of power to build. Roughly half of that is for data center and AI growth.
There are five things we can build in the next four years at scale to address that collective amount. First, it’s transmission — the transmission buildout will help to get a modern grid to enable power flow to where it’s needed in a much more effective way. That’s the first step because if we just build all that power, the current grid can’t handle it.
Second, there are four supply technologies that can be built: solar, batteries, wind, and natural gas. All four of those technologies, we know there’s enough equipment here in the U.S. available for purchase that we can build at volume. And I’ll say this — natural gas is only about 10% of all those gigawatts because of the availability of turbines from suppliers. You can’t get enough over the next four years. So when I talk about decarbonization, most of what is built to address this issue is zero-carbon resources, renewable energy resources.
If you were to compare the current conversation around data center development to the debate over developing renewable energy in the U.S. — or energy in general — do you see any similarities or differences?
There are always issues with permitting projects. Communities are always going to have concerns about what’s built in their backyards.
What’s new — and your polling shows this — is the level of concern communities have. But here’s the thing: Most of this can be overcome by developers going in, listening to what the needs of the communities are, then responding and through the permitting process addressing those concerns. You can’t do that 100% of the time. But my experience is, when you take that sort of approach, you can overcome a lot of it.
Most of the large data centers are actually doing the things I’m discussing — going in and saying, Look, we want to be grid interconnected because grid connection at the end of the day means the resources we’re bringing to bear are also going to make a stronger grid. Number two, it's investing in power generation sources like the ones I said — and those power sources will be on the grid, so they’ll solve for the increased power demands of a community.
Third, water. They should bring the water solutions. You’re seeing data centers coming in and saying it head on now, that they have closed-loop systems or whatever the solution is. At the end of the day, the communities they’re proposing these in have a real negotiating opportunity to make sure they’re holding the data center developers accountable to the needs of the community.
For a community to say we don’t want it here misses a real opportunity for those communities to get the power they need, the grid they need, and the ability to bring down energy costs.
How is the data center debate affecting permitting reform conversations in Washington, from your perspective?
Permitting reform in the U.S. at the state and federal level has been broken for years. The SunZia transmission project? It took 17 years to permit. Ribbon-cutting is in a week or two and there’s still litigation around it. From a business perspective, it’s just untenable, and it’s a miracle that the project is getting built. Developers need a chance to come in and have their project evaluated. Both the community and the developer should be able to get to a go or no-go in a couple of years on one of these projects.
How is data center growth affecting the permitting reform discussion? It’s a very hot issue right now. Right now I think in part because the data center issue is so huge — because we’ve only got four years to solve for the first really big tranche of power we need and prices across the board for electricity are escalating — this is coming to a head. The data center load is a part of the catalyst to get people talking about it [permitting reform].
Do you expect legislating in Congress on permitting reform this year? Anything beyond more conversation?
My hope is that we get a bill. A few weeks ago someone from the administration was quoted as saying they wanted a framework for a bill by the end of May, and it’s June now. We haven’t seen both sides or the administration coalesce around a final project yet.
We’re in a midterm election cycle. Typically it’s very difficult during these cycles to move bills like this. At the same time, with electricity prices increasing and the need to build more, to fix this, I’m very hopeful something will come together. And look at the Senate — you’ve got Republicans and the Democratic ranking members talking about this. It’s all good signs.
If everyone’s talking about energy and affordability during this election, isn’t that a good thing for action in the next Congress?
I’ll say this: You’re seeing the catalyst for it right now with prices rising, and almost every grid operator around the country has raised concerns about shortages at some point this year or next year. It’ll hopefully be enough to have policymakers do something about it this year.