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We’ve built a startling amount of the world’s energy supply on things you can only use once. A tank of petrol burns for a few hundred kilometres and then it’s gone, and someone has to drill, refine and ship the next tank from scratch.

A cornfield grown for ethanol runs on the same logic with even more labour and environmentally damaging steps tacked on: it takes an entire growing season to produce one crop, that crop then has to be harvested, trucked, milled, fermented and then distilled into a fuel, and the fuel gets burned in an engine at a 30% less productive rate than the fuel it's replacing, exactly once before the whole cycle, planting to processing to combustion, starts again from zero. I'm no scientist, or an Economist, but that my friends, is a shitty system.

A solar panel doesn’t work like that. It gets manufactured once and then quietly keeps producing new electricity every single day the sun comes up, for twenty five years or more, with very little maintenance and no repeat industrial process required to make each day’s batch of power usable. Nothing needs to be burned, refined, or grown again next spring. It just needs a wire. That difference, a single-use fuel versus a durable generator, is the whole argument of this piece before we even get to the numbers.

Somewhere in the American Midwest, farmers are currently pointing several hundred acres of prime agricultural land at the sky, waiting for photosynthesis to slowly assemble a substance that won’t be eaten, but will later be set on fire inside an engine. This is, when you say it out loud, an rather unhinged way to make energy. It is the energy equivalent of posting someone a letter by first turning the paper into a paper aeroplane, throwing it out the window, having a truck drive it to the post office, and then having the post office set it on fire for warmth. And yet this is exactly what happens to roughly forty per cent of the corn grown in the United States every single year, with ethanol manufacturers using about 40 percent of the U.S. corn crop for ethanol and related co-products, most of which is consumed domestically as transportation fuel.

Corn is not just food. Today, it is, disproportionately, fuel. And once you follow that fuel from seed to petrol tank, you start to understand why so much farmland on four continents is currently doing a far worse job of generating energy than a field full of mirrors would.

Here is the geography bit, because geography matters a whole lot more than the ethanol lobby would like us all to know.

Most of the world’s corn-for-fuel is grown in temperate climates with one growing season a year. The American Corn Belt (Iowa, Illinois, Nebraska, Indiana) gets one planting and one harvest, dictated by frost dates. American farmers planted an estimated 98.7 million acres of corn in 2025, the most since 1935, and virtually all of it goes through the ground exactly once before winter shuts the whole operation down.

The same applies further afield. Central and eastern Europe grow maize for bioethanol across Hungary, Romania and neighbouring states, where corn is the dominant ethanol feedstock, while wheat dominates further north and west, and that too gets one crop before the frost arrives. The United Kingdom doesn’t actually grow much corn for fuel at all (more on that shortly), and Australia’s ethanol industry leans on wheat, sorghum and sugarcane rather than corn, with wheat destined for ethanol production representing only about one per cent of the national wheat crop. Brazil is the interesting exception, because its Center-West region can squeeze in a second corn planting after soybeans thanks to a longer growing season, and its ethanol sector has exploded as a result.

The point stands regardless of which of these places you’re in: a cornfield is a seasonal, single-shift energy asset. It works seven or eight months a year if you’re generous, less if the weather misbehaves. A solar panel works every single day the sun rises, all year round, and doesn’t care about frost, drought, hail or the price of diesel for the combine harvester.

Growing the corn is only step one. To get from a cob to something you can put in a fuel tank, that corn has to be harvested, trucked to a biorefinery, milled, cooked, fermented with enzymes and yeast, distilled, and then dehydrated to strip out the water left over from fermentation. Every one of those steps burns energy, mostly in the form of natural gas and diesel.

This is why energy economists measure biofuels using something called Energy Return on Investment, or EROI: how much usable energy you get out for every unit of energy you put in. For corn ethanol, the consensus estimate sits around 1.2 to 1, meaning that at that ratio, 80 per cent of the energy generated is offset by the energy required to produce it, leaving a net energetic return of only about 20 per cent. That’s already quite unimpressive, but here’s the massive oversight: even with that slight improvement, after all that energy has been spent growing and distilling it, the ethanol you end up with carries roughly a third less energy than the petrol it’s being blended into, about 76,000 BTU per gallon against gasoline’s 114,000, a shortfall that shows up later as lower mileage every time you fill up. Some analyses using wider system boundaries put corn ethanol’s EROI below 1, meaning the process is a net energy sink: you put more energy in than you get out, and the only reason it happens at all is that the input energy (diesel, natural gas, fertiliser) is cheaper per unit than the output energy (liquid fuel) is worth. This isn’t some ingenious an energy strategy. It’s an absurd subsidy with dirty tractors in tow.

Compare that to solar photovoltaics, which typically comes in around 8 to 1, meaning only about 12 per cent of the energy produced is offset by production requirements, for a net return of roughly 88 per cent. Put simply, for every unit of energy you spend building and installing a solar panel, you get roughly seven units back. For every unit of energy you spend growing and processing corn into ethanol, you get about a fifth of a unit back, on the more optimistic estimates.

Say you’ve done all that work and successfully converted a field into a tanker of ethanol. What have you actually got? A fuel with meaningfully less energy in it than the petrol it’s replacing.

Pure gasoline carries around 114,000 BTU per gallon, while pure ethanol carries about a third less, at roughly 76,000 BTU. That gap is why the standard American E10 blend (ten per cent ethanol) already runs at about 98 per cent of pure gasoline’s energy content, and why the newer E15 blend loses more mileage again, with real-world testers reporting fuel economy drops in the low single digits, roughly 1.5 to 5 per cent depending on whose numbers you trust. You are, in effect, watering down your fuel with something that took a full growing season, a fleet of diesel trucks and a chemical plant to produce, and it still performs worse than what it’s diluting. This is… A shitty system.

Here’s where the numbers stop being just disappointing and start being genuinely absurd.

The United States currently dedicates about 29.7 million acres, roughly 12 million hectares, an area about the size of New York State, to growing corn purely for ethanol fuel. A 2025 study from Cornell University’s Department of Natural Resources and the Environment, published in the Proceedings of the National Academy of Sciences, did the maths on what happens if you swap that land for solar panels instead. The finding was that utility-scale solar generates the same amount of energy as corn ethanol using just 3.2 per cent of the land footprint, meaning one hectare of solar produces what would otherwise take roughly 31 hectares of corn ethanol.

Read that again:

You could take three per cent of America’s ethanol cornfields, cover them in panels, and match the energy output of the other ninety-seven per cent.

The researchers went further, identifying real, technically feasible sites within two miles of existing transmission lines. Converting about 391,000 hectares, just 3.2 per cent of the total ethanol-corn footprint, would generate roughly 380,000 gigawatt-hours of electricity a year, while lifting utility-scale solar’s share of the American grid from 3.9 per cent to 13 per cent. Scale that per-hectare generation rate up across the full 12 million hectares currently growing ethanol corn (a straightforward extrapolation the study itself doesn’t make, but the underlying generation rate does), and you land somewhere in the region of 11,000 to 12,000 terawatt-hours a year. For context, the entire United States generated 4.43 thousand terawatt-hours of electricity in 2025, a record high. Converting every acre of America’s ethanol cornfields to solar wouldn’t just cover the country’s electricity needs. It would produce something like two and a half to three times the entire nation’s current electricity demand, from a single land-use swap, using land that’s already been cleared, ploughed and wired up for a much stupider purpose.

I don’t even need to go that far to make the point. The Cornell team already calculated that converting just 46 per cent of America’s ethanol cornfields to solar would generate enough electricity to hit the country’s 2050 grid decarbonisation target on its own. Not “help towards it”. Do it. With less than half the land currently growing fuel that, as established above, barely breaks even on energy.

A separate, peer-reviewed comparison from researchers working with Clean Wisconsin found a similarly damning gap when measured in vehicle miles rather than raw energy: one million acres of Wisconsin cornfields grown for ethanol can power about ten billion internal-combustion vehicle miles a year, or 23 billion electric vehicle miles if that ethanol’s energy were instead converted to electricity, whereas the same acreage covered in solar panels could generate enough electricity to power 804 billion electric vehicle miles annually, an 84-fold gap in land efficiency once you account for how much more efficiently electric motors use energy compared with internal combustion engines.

There is no honest reading of this data in which corn ethanol comes out ahead. The only reason it still exists at the scale it does is politics, not physics, not maths, and certainly not logic.

Here’s the part the free-market cheerleaders should be angriest about, because this isn’t even a case for sacrificing profit for the planet. It’s the rare case where the more responsible option is also the more profitable one.

Corn typically nets a farmer somewhere between fifty and two hundred dollars an acre a year, depending heavily on commodity prices, and in weaker years it has dipped into outright losses, with Illinois growers estimated to have lost over a hundred dollars an acre in one recent downturn. Meanwhile, solar developers are paying landowners somewhere between five hundred and over a thousand dollars an acre a year to lease that same land, on twenty to thirty five year terms with built-in annual increases, plus signing bonuses, and crucially, zero input costs. No seed. No fertiliser. No diesel. No crop insurance. No gambling on a weather system three thousand miles away deciding whether your year’s income survives.

This is about as close to a risk-free income stream as land ownership gets. You are being offered guaranteed, escalating rent for doing precisely nothing to a field beyond letting a company bolt some racking into it, and a meaningful share of the corn belt is turning it down in favour of a crop that, once you account for the energy cost of producing the fuel it becomes, barely breaks even.

Many will point out that rooftop solar isn’t for everyone, and they’re right, it isn’t, particularly in countries where the grid is already reliable and centralised. But that’s precisely the point in corn ethanol’s favour that nobody making the argument seems to notice: utility-scale solar on former cornfields doesn’t require the grid to change at all. It plugs into the same transmission infrastructure that already exists, often within a couple of miles, because these are farms, and farms already have power running to them. There’s no extra processing step, no refinery, no fermentation tank, no distillation column. Electrons go from panel to substation to consumer. That’s it. It is, almost annoyingly, the simplest possible version of the energy supply chain, sitting right next to the most convoluted one.

United Kingdom. Britain’s bioethanol industry barely touches corn at all, running mostly on wheat, though the country’s history here is more a case study in policy self-harm regardless of the feedstock. The country’s largest bioethanol plant, Vivergo in Hull, shut down at the end of August 2025 after the government removed tariff protection on American ethanol as part of a trade deal, and its sister plant Ensus in Teesside, which had historically favoured imported maize over domestic wheat as its feedstock, only survived after a £100 million government rescue. Whatever you think of the wheat-versus-corn distinction, the underlying story is the same one playing out globally: enormous public money propping up a fuel category that a field of solar panels would outperform without needing rescuing at all.

Latin America. Brazil is the great outlier here, because it undermines the industry’s usual excuses. Brazilian corn ethanol has gone from a standing start to a genuine industry in under a decade: production jumped from 140 million litres in the 2015/16 season to an estimated 8.2 billion litres in 2024/25, now accounting for roughly 22 per cent of the country’s total ethanol output, concentrated almost entirely in Mato Grosso’s Center-West region. It’s growing because the region can grow a second corn crop after soybeans, which makes it more land-efficient than the American model. Even so, none of that changes the underlying physics: an EROI of roughly 1.2 to 1 still doesn’t improve because you managed to plant the corn twice.

Europe. The EU’s bioethanol mix runs on wheat, sugar beet and maize depending on the region, with maize accounting for around 4.1 million tonnes of feedstock against 3.9 million tonnes of wheat and 12.1 million tonnes of sugar beet, maize production concentrated in central and eastern member states with the right climate. Every hectare of that maize belt sits in a temperate, single-harvest climate, subject to exactly the same seasonal, EROI and energy-density limitations as the American Corn Belt.

Australia. Genuinely doesn’t grow much corn for fuel, leaning on wheat, sorghum and sugarcane molasses instead. But the country is currently in the middle of an active push for a national ethanol and biodiesel mandate, with major farming and manufacturing bodies lobbying government in 2026 to expand the sector on fuel security grounds. It’s the same argument, dressed in different feedstocks, and it should get the same scrutiny before a single extra hectare gets committed to it.

Corn gets the headline because it’s the biggest single offender, but it isn’t the only crop currently being conscripted into a fuel role it’s fairly mediocre at. Rapeseed, sold in supermarkets as canola oil, has been quietly doing the same job across Europe for two decades, and the energy maths behind it is arguably worse.

Germany and France are Europe’s two biggest rapeseed growers, planting just over 1.11 million hectares in Germany and around 1.27 million hectares in France for the 2025 harvest alone, out of roughly 5.8 million hectares grown across the EU as a whole, a meaningful share of which exists specifically to be pressed into biodiesel. Germany’s biodiesel industry alone processed an estimated 1.45 million tonnes of rapeseed oil in 2024, using up more or less the entire domestic rapeseed harvest for that year. Poland, Romania, the Czech Republic, Hungary, Denmark and the UK all grow it at scale too.

The energy return also isn’t great. A peer-reviewed mapping study of rapeseed biodiesel across the EU found EROEI values of 2.2 or lower in every member state assessed, concluding that rapeseed biodiesel production in Europe is, energetically, not a viable option. That’s better than corn ethanol’s roughly 1.2 to 1, but it’s still only a rounding error compared to solar’s 8 to 1, and it’s being achieved on land that, in northern Europe especially, gets even less annual sunshine than the American Midwest.

Canada tells a slightly different version of the same story. It’s the world’s largest producer of canola, the low-erucic-acid variety of rapeseed, and while a large share of that crop genuinely goes to cooking oil rather than fuel, an increasing slice is being pulled into renewable diesel production as North American biofuel mandates expand. The crop, the acreage and the seasonal single-harvest limitation are all identical to corn’s. Only the colour of the field changes, from green to a startling, photogenic yellow.

The pattern repeats itself with palm oil in Indonesia and Malaysia, soybean biodiesel in the US and Argentina, and sugarcane ethanol in Brazil, each with its own regional politics and its own devoted lobby insisting this particular crop is the exception. None of them change the underlying physics. A field that has to be replanted every year to keep producing a fuel that gets destroyed the moment it’s used will always lose to a piece of equipment that gets built once and keeps producing indefinitely. I called this peace the stupidest thing we grow, I don't mean corn is stupid if we grow it to eat. But we don't live in the Victorian era anymore, in this day and age anything that we grow or extract from the ground we should be using to build and make things with, burning it, that’s just backward.

Any piece making this argument will attract the same handful of comments, usually from people with a professional stake in the answer. Worth dealing with them properly.

“Solar panels take fossil fuels to manufacture too.” True, and already priced in. The 8 to 1 EROI figure used earlier isn’t solar’s raw output, it’s what’s left after subtracting every input required to get there: mining, manufacturing, shipping, installation. Corn ethanol’s 1.2 to 1 is calculated the same way. Even accounting for everything it takes to build a panel, solar still wins by a factor of nearly seven.

“Solar doesn’t work at night, so this is dishonest.” Also true, and beside the point. We’re not proposing solar as 100 per cent of the grid. The argument is narrower than that: this specific land, currently growing a fuel that barely breaks even on energy, would do more good generating daytime electricity than it currently does growing ethanol. Wind is a genuine complement for the night-time gap and it can sit side by side. None of that changes which crop is the worst-performing asset in the paddock.

“Fine, but the batteries needed to store that power just become toxic waste in fifteen years.” This is the one that sounds the most damning and holds up the least. Grid-scale lithium-ion batteries typically run for fifteen to twenty years of service. When they do reach end of life, the materials inside them don’t vanish the way burned fuel does, they can get chemically extracted and put back into circulation. Modern hydrometallurgical recycling routinely recovers 95 to 99 per cent of the cobalt and nickel in a spent battery, and 70 to 95 per cent of the lithium, along with the copper, manganese and aluminium, all of it purified to a standard that lets it go straight back into new batteries. It isn’t a rounding-error footnote, it’s the entire material basis of the battery being reusable rather than destroyed. When we mine for things like lithium, we should be doing so with a mindset of, mine once and reuse. Yes, there will be some loss and we would still need a few lithium mines. There are currently more than 34 lithium mines in commercial operation worldwide, according to mining industry tracker GlobalData, and processing is even more concentrated than extraction, with China alone handling somewhere between 65 and 73 per cent of the world’s lithium refining capacity depending on the estimate. Both stages, mining and processing, come with real environmental cost wherever they happen. A genuine shift toward mine once, recover and reuse wouldn’t eliminate that footprint, but it would mean the industry stops needing to open new mines and build new refining capacity at the current pace just to keep pace with batteries being thrown away rather than recovered.

It’s worth being honest about the catch: current collection rates for spent batteries are still low, estimated at only 2 to 5 per cent across the US, EU and Australia, mostly because household electronics get binned, or left in a drawer rather than returned. That’s a real problem, but it’s a collection and policy failure, not a chemistry problem, and it’s a strange echo of the earlier point about ethanol’s sunk-cost infrastructure. The materials are recoverable. Whether anyone bothers to recover them is a separate, solvable question. Even if they aren’t and every piece of used equipment went into landfill (which at this game it absolutely wouldn’t) but let’s say it did, we’re talking about products that only need to be disposed of once every 15 to 25 years. Remember the alternatives: oil, gas or coal can only be used once. A gallon of burned ethanol has no equivalent second act to fail to arrange. Once it’s combusted, there is nothing left to recycle, collect, or regret not collecting.

“This will cost rural jobs and hurt farmers.” Already covered in the business case section, and worth repeating because it’s the argument the industry leans on hardest. Solar leases currently pay farmers more per acre, guaranteed, for doing less, than corn grown for ethanol nets them in an average year. This isn’t asking farmers to sacrifice income for the planet. It’s pointing out that a meaningful number of them are turning down a better deal because the worse one is more familiar.

“What about the ethanol plants, the blending mandates, the equipment already bought?” The one genuinely honest objection on this list. Billions have already been sunk into ethanol refineries, blending infrastructure and mandated purchase volumes, and none of that disappears because a Substack article points out the physics doesn’t add up. That’s a real problem. It explains why the system persists. It doesn’t make the system any less wasteful while it does.

“Solar panels end up as toxic landfill waste.” Panel materials, glass, aluminium, silicon, small amounts of silver, are recoverable and increasingly recycled at end of life. A 2024 report from Columbia Law School’s Sabin Center for Climate Change Law examined this claim specifically, alongside thirty two other pieces of common renewable energy misinformation, and found most of them false or missing critical context.

None of these objections are stupid to raise. They’re just, on inspection, either already accounted for in the numbers above, or true but irrelevant to the specific comparison this piece is making. The corn is still the problem.

None of this is an argument against farmers, against biofuels research broadly, or against the people trying to make a living off difficult land. It’s an argument against a specific, decades-old policy choice that has locked tens of millions of acres worldwide into producing a fuel that barely returns more energy than it costs to make, when the same land, doing almost nothing differently in terms of grid connection or logistics, could be quietly generating several times the total electricity the country actually needs.

Corn is a remarkable plant. It feeds people, it feeds livestock, it’s genuinely good at what it does. What it is spectacularly bad at is pretending to be an oil well. We’ve just spent fifty years subsidising the pretence and most countries right now are complaining that they can't produce enough electricity, not only is that not true, with the current economies of scale, we can practically do it for free.

The Stupidest Thing We Grow...

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