Solar Parks: What a Terrible Idea

Let's establish what this article is not, because the title will attract people hoping for something else. It is not an argument against solar — we'd be a strange engineering firm to make one, given what we do all day. Nor is it the "solar farms will starve Britain" apocalypse, which the numbers, as you'll see, do not support. It is an argument about priority — and, we'll be candid, about principle: good food needs good land, and this country is not so rich in either that it can afford to confuse the two. Covering productive farmland with panels while millions of square metres of commercial roof sit bare — roofs with grid connections already nearby and hungry loads underneath — is a failure of sequencing that ought to embarrass everyone involved in energy policy.

First, the honest numbers — including the ones that don't help us

Ground-mounted solar in the UK covered an estimated 21,200 hectares at the end of September 2024 — about 0.1% of the country's land area.[1] Satellite mapping puts the median footprint at 2.25 hectares per megawatt.[2] So let's kill the scare story first: solar parks are not, in aggregate, a meaningful threat to British food supply, and anyone waving that particular flag is doing arithmetic with their gut. If we said otherwise we'd be as guilty of vibes-based reasoning as the brochures we mock.

But watch the denominator, because "0.1% of the country" is the developer's favourite framing and it flatters. Most of Britain's surface was never on offer to either panels or ploughs — it's moor, mountain, bog, woodland and town. The land both sides actually want is the flat, drained, accessible fraction, and that fraction is small: the UK's croppable area is about 6.2 million hectares, a third of the farmed total.[11] Measure solar's take against that — the only honest comparison, since it's the only land in contention — and you get roughly 0.34%: more than three times the headline figure, and climbing. (A pedant will note that not every array sits on croppable land — true, though two-thirds of the biggest do sit on productive farmland — but it's the flattering denominator we're correcting here, not the numerator.) Still no famine. But the pressure on good flat land is real precisely because there is so little of it, and every competing use knows it.

But "small in aggregate" is doing a lot of work in that sentence, because the land being taken is not random land. CPRE's analysis of the largest solar farms found two-thirds built on productive farmland, including 827 hectares of officially designated Best and Most Versatile land — the Grade 1, 2 and 3a soils that grow most of what Britain grows. That's 45 hectares of Grade 1 "excellent" land under glass and steel.[3] And the trajectory matters more than the snapshot: if the UK keeps deploying solar in the current rooftop-to-field proportions, the projected requirement rises to somewhere between 0.45% and 0.82% of agricultural land.[2] Still not a famine — but concentrated in particular counties, on particular soils, in particular communities who can be forgiven for noticing that the panels always seem to land on the good flat fields near the substation.

Which is, of course, exactly why they land there. Flat, well-drained, close to a grid connection: the qualities that make land good for arrays are substantially the qualities that make it good for arable farming. The conflict isn't a coincidence; it's baked into the siting logic.

And here's the context that turns "small in aggregate" into "wrong direction". The UK now produces just 60% by value of the food it consumes, down from around 78% in the mid-1980s — and yes, in fairness, the most recent drop owes as much to import prices as to production volumes.[8] But look at the crops that actually need good ground: self-sufficiency in fresh vegetables is at 53%, the lowest since records began; fresh fruit, 16%; tomatoes, 15%.[8] The categories where Britain leans hardest on imports are precisely the ones that demand quality soil and a kind climate — and the continental growers we import from are having an increasingly rough decade of their own. Meanwhile the same finite acres are being bid for by housing, infrastructure, forestry and environmental schemes all at once. So we'll state our position plainly rather than hide it in a priority list: we're against putting solar parks on productive farmland. Not because any single array threatens the national food supply — it doesn't, see above, and we won't pretend otherwise — but because a country growing barely half its own vegetables should be treating Grade 1 soil as strategic infrastructure, not as the cheapest flat surface near a substation.

Meanwhile, directly above the grid connections

Now look up. The UK Warehousing Association surveyed its own sector and found the largest 20% of warehouses alone offer around 75 million square metres of roof, capable of hosting roughly 15 GW of solar — enough, at the time of the study, to double the UK's entire installed solar capacity. Total unused warehouse roofing came to about 18,500 acres.[4] A separate industry estimate puts total warehouse roof space at over 165 million square metres, with potential for around 25 GWp.[5] At the time of the UKWA study, roughly 5% of warehouses had any solar at all.[4]

And warehouses are only the opening act. Research commissioned by CPRE from the UCL Energy Institute mapped England's rooftops and developed spaces — commercial, industrial, domestic, new-build and car parks — and found potential for up to 117 GW: more than the government's entire 70 GW national solar target for 2035, with 40–50 GW deliverable from existing roofs and car parks (car parks alone: 11.4 GW) within that timeframe.[9] The built environment could, on the published numbers, carry the whole programme.

The domestic half of that story is further along than the commercial one, and still barely begun: about 1.95 million UK homes now have solar — roughly 5.7% of households, with our own South West leading the country at 8.5% — and installations are running at record rates.[10] Encouraging, and yet: nineteen roofs in twenty, bare.

Hold the numbers side by side. Every solar park in Britain, fought through planning one hedgerow battle at a time: 21,200 hectares. Warehouse roofs, sitting empty, requiring no land, no planning war, and no new landscape: 18,500 acres — about 7,500 hectares — on the association's own count, before you touch factories, retail sheds, car parks or the nineteen bare home roofs in twenty. And the roofs come with three advantages no field can offer:

• The grid connection already exists. A warehouse is a wired building. The transformer, the switchgear, the import capacity — bought and paid for, sitting directly below the empty roof. Solar parks, meanwhile, queue years for new connections, and connection scarcity is one of the loudest complaints in the entire industry.
• The demand is directly underneath. Warehouses, factories and cold stores consume electricity in daylight hours — which is when panels produce it. Generation at the point of use doesn't traverse the transmission system, doesn't need a new pylon argument, and displaces retail-priced electricity rather than earning wholesale export rates, which makes the economics better per kWh, not worse.
• Nobody has to lose anything. No tenant farmer displaced, no village consultation, no glint-and-glare study. The most controversial thing about a warehouse roof array is that nobody can see it.

So why do the fields keep winning?

Because — and here's the steelman, honestly presented — a field is administratively easy and a thousand roofs are administratively hard. A developer can sign one lease with one landowner, order panels by the field-load, and build at a cost per megawatt that rooftop work struggles to match. Rooftop solar at national scale means negotiating with thousands of building owners, and the incentives are genuinely tangled: the landlord owns the roof but the tenant pays the electricity bill, so neither is sure why they should fund the other's savings. Tenancies run shorter than payback periods. Some older roofs need structural assessment, and some fail it. Export limits bind. None of this is imaginary, and pretending the rooftop route is free of friction would be exactly the kind of brochure-talk we exist to avoid.

But notice what kind of problems those are. Not one of them is a physics problem. They are lease structures, split incentives, survey costs and connection paperwork — coordination failures, the sort of thing policy exists to fix and occasionally does. France looked at this in 2023 and simply legislated: outdoor car parks over 1,500 m² must shade at least half their area with solar canopies, on deadlines running to 2028, with fines for shrugging. (And in the interest of full honesty: French parliament has since softened it — trees now count toward the coverage requirement — because no policy survives contact with lobbying entirely intact.)[6] Britain, by contrast, debates each 200-acre solar park individually in public anguish[7] while its warehouse roofs do nothing but keep the rain off.

Where ground-mount genuinely makes sense

Fairness demands the other side of the ledger. Britain has plenty of land that is neither productive nor pretty: brownfield, former quarries, capped landfill, Grade 4 and 5 soils that break ploughs and hearts. Arrays there take nothing from anyone. Sheep grazing under and around panels is real and works — the panels return the favour with shade and shelter. And there's a more interesting option still: designing arrays so that farming continues between and beneath them, deliberately — a discipline called agrivoltaics, which has produced some genuinely surprising field-trial results, and which we'll take apart properly in a separate article.

The verdict

Solar parks on good farmland are a lazy default dressed as green progress, and we're against them. The aggregate land take is small and the famine rhetoric is unsupported — we hold that line because the numbers do — but a country growing barely half its own vegetables, on an island where housing, forestry, nature and energy are all bidding for the same acres, should not be spending its best soil on a job a roof can do. Every array on Grade 1 land is a monument to the same fact: it was easier to take a field than to organise a rooftop. On the published research, England's roofs, car parks and developed spaces could carry the entire national solar programme — sitting above existing grid connections, above the very loads they would serve, waiting for lease law and incentive design to catch up with engineering common sense. Until that happens, we'll keep saying the quiet part in public: the best site for a solar panel is a roof that's already doing nothing, above a meter that's already spinning.