What Actually Happens When It Wears Out

"And what happens to all this kit when it dies, then?" is the best question we get asked, and it deserves better than the two standard answers: the brochure's breezy "it's all fully recyclable!" and the saloon bar's confident "it all goes to landfill." Both are wrong, in instructive ways. This article is the actual answer — the law, the logistics, what genuinely gets recovered, and what currently gets burned or shipped abroad while the industry works out something better.

A disclosure before we start, in both directions: we're members of PV Cycle, the solar industry's take-back and compliance scheme, so we pay into the system we're about to describe — read that as either "they know how it works" or "they would say that", at your pleasure. The references are at the bottom either way.

Solar panels: heavy, simple, and harder than they look

Start with what a crystalline silicon panel actually is, by weight: roughly 76% glass, about 10% polymer (the encapsulant and backsheet), 8% aluminium frame, 5% silicon, around 1% copper, and less than 0.1% silver.[1] No mystery goo; mostly a window in a picture frame with some very refined sand inside.

The law: someone already paid for the funeral

In the UK and across Europe, solar panels fall under the WEEE regulations — the same producer-responsibility law that covers your washing machine. Anyone who manufactures, imports or rebrands panels is legally a "producer" and must join a Producer Compliance Scheme that finances the collection, transport and treatment of panels at end of life. PV Cycle UK is the PV-specific, government-approved, not-for-profit scheme: members report the tonnage they place on the market and pay fees that fund the take-back and recycling machinery.[2]

The practical upshot for a customer is easy to state and worth stating: the recycling of the panels on your roof is pre-funded by law. When they eventually come down, they go into a collection route that already exists — not into a skip, and not into a "we'll work it out in 2050" promise. It's one of the quieter achievements of European waste law: the funeral was paid for at the point of sale.

Our own membership is voluntary: we're an installer, not a manufacturer or importer, so the producer obligation doesn't fall on us — we joined anyway. Here's what that looks like in practice, stripped of romance. We accept old domestic panels free of charge, and commercial quantities for a small handling fee (£10 plus VAT per panel as of 2026, conditions apply — storage space and shipping aren't free). Panels get stacked on pallets, wrapped, and stored until there's enough to make a collection worthwhile, then shipped into the recycling chain. It is, candidly, a pain: they're bulky, the pallets eat workshop space, and there's no income in it whatsoever. We do it because an installer who fits kit for a living ought to have an answer to "where does it go?" that doesn't involve a skip. And one admission we think matters more than any brochure claim: the volumes reaching us are tiny, and where most of Britain's retired panels are currently ending up, we genuinely don't know. The take-back machinery exists and is funded; the early waste stream is still finding its way into it. If you have old panels, you now know one place they can go.

The honest bit: recycled by mass, not yet by value

Now the part the brochures skip. When you see "95% recyclable" on a panel datasheet, remember the composition above: glass and aluminium are 84% of the weight, and both are eminently recyclable. The frame comes off and rejoins the aluminium stream — one of the best recycling loops humanity runs. The cabling and junction box give up their copper. So the headline mass-recovery number is real, but it's mostly achieved by the heavy, cheap materials.

The awkward truth is what happens to the clever 5%. In most of today's commercial processes the glass is shredded and sold as low-value contaminated cullet rather than returning as flat glass — downcycling, not recycling. And the silicon and silver — the components that carry most of the panel's embodied energy and most of its material value — are largely not recovered at commercial scale. The villain is the encapsulant: a polymer engineered to hold a panel together through thirty years of weather does not politely let go on request, and today it's typically burned off or landfilled with the residue. Laboratory and pilot processes now demonstrate silver recoveries of 95–99% and promising silicon recovery, but no commercial process yet recovers everything worth recovering, and the high-value plants are only beginning to scale.[3]

Inverters: the first thing to die

The component nobody asks about is the one most likely to wear out first. The inverter — the box converting your panels' DC into usable AC — works hard every daylight hour, and a typical string inverter lasts 10–15 years against the panels' 25–30. The usual cause of death is mundane: electrolytic capacitors, which age faster than the silicon around them, especially when the box is mounted somewhere hot and unventilated. Microinverters — one small inverter per panel, up on the roof — fail less often per unit and now carry warranties up to 25 years,[8] but we'd urge you to do the whole-system arithmetic before being seduced: a typical domestic job carries ten to fourteen of them, so the fleet gets more chances to produce a failure than one box does, and when a unit does die it's bolted under a panel on the roof. Replacing it means scaffolding — often more than the cost of the part, sometimes more than a whole string inverter — whereas a string inverter fails at head height next to the consumer unit and swaps out in an afternoon. The warranty covers the part; it does not cover the scaffold. Either way, if you own a solar array long enough, you will buy power electronics again — which is why the honest payback calculations (including the energy-payback figures in our embodied energy article, whose system boundaries assume a 15-year inverter life) build a replacement into the maths rather than hoping you won't notice.

At end of life an inverter is ordinary WEEE — the same producer-financed collection machinery as the panels — and materially it's a mixed bag: a case and heatsink of aluminium, copper windings and busbars, and printed circuit boards. The metals recycle well. The boards are the honest weak point of all electronics recycling: they go to smelters that recover the copper, gold and silver, which is genuine recovery, but partial and energy-hungry, and the fibreglass substrate is lost. There is no pretending a PCB is a closed loop yet; it's a one-way trip that salvages the valuable passengers.

Which is why the better answer, wherever possible, is the one higher up the hierarchy: repair. A dead inverter has very often died of one capacitor, a fan, or a relay — a few pounds of components in a few hundred pounds of equipment. We do board-level diagnosis and repair on our bench, and we'll be honest that it's fiddly, occasionally infuriating work we perform out of principle rather than pleasure — but it beats scrapping a functioning power converter over a £3 component, and it can turn a fortnight's supply-chain wait into a same-week fix. Whether repair is viable depends on the manufacturer: some publish schematics and sell spares, others pot their boards in resin and would rather sell you a new unit. Worth asking about before you buy, not after it dies — "can this be repaired?" is a question that improves the industry every time a customer asks it.

Batteries: the law is ahead of the plumbing

Batteries are where regulation has recently grown real teeth. The EU Battery Regulation of 2023 sets hard, dated targets: by the end of 2027, recyclers must recover 90% of the cobalt, copper, lead and nickel in waste batteries and 50% of the lithium — rising to 95% and 80% by the end of 2031. From 2031 new batteries must contain minimum recycled content, with the percentages ratcheting again in 2036.[4] Whatever you think of Brussels paperwork, this is the correct shape for the incentive: it makes the materials in a dead battery a legally-mandated resource rather than an inconvenience.

The UK reality on the ground is less tidy, and we'll describe it as it is. Most lithium battery "recycling" in Britain today means shredding into black mass — a coarse powder of cathode and anode materials — much of which is then exported for the actual metal recovery, because the UK has shredding capacity but very little domestic refining. In the words of one UK recycler's co-founder: "we take a waste battery and then we shred it and create another waste material," most of it shipped overseas.[5] That is changing, at industrial pace rather than press-release pace: the UK's first industrial-scale lithium battery recycling plant opened in 2023 with a 22,000-tonne permit, and — pleasingly for a firm on the Cornish side of the Tamar — one of the most advanced UK ventures in actually refining black mass into battery-grade materials is building its scale-up plant in Plymouth, with a larger Teesside facility planned.[5][6]

Two honest footnotes to that. First, a battery that's lost capacity hasn't necessarily died — EV packs too tired for the motorway can serve years more in stationary storage, where weight and density stop mattering; "second life" is a genuine route, though warranty, battery-management and certification questions mean it's still more engineering project than commodity. We can vouch for the route first-hand: we've repurposed packs into stationary storage ourselves, and we're now looking seriously at EV battery pack repair — because we keep hearing of packs written off for the sake of one duff cell among hundreds, which offends the engineer and the accountant in us simultaneously. Repair before repurpose before recycle: the waste hierarchy applies to batteries as much as to anything else, and the earlier rungs are where the value is. Second, not everything in a cell comes back: electrolytes and graphite are today mostly lost or burned in processing, and the recovery targets above are targets, not history. The direction is right; the plumbing is being built in public, on dated deadlines you can check.

Heat pumps: the most boring section, thankfully

A dead heat pump is, to a scrap merchant, a familiar and rather attractive object: a steel case around a copper-wound compressor, copper and aluminium heat exchangers, a motor, some electronics. These are conventional metals with centuries-old, profitable recycling chains — nobody needs a subsidy to want the copper out of a condenser coil. The box itself is arguably the most recyclable object we install.

The part that matters is the kilogram or two you can't see: the refrigerant. Under the F-gas regulations it is illegal to let it escape, and recovery at end of life is mandatory — performed by an engineer holding F-gas certification (and a certified company; the individual ticket alone isn't enough for commercial work), extracting the charge into sealed cylinders before the unit is scrapped. The recovered gas is either reclaimed to specification and resold, or destroyed. Records of what was recovered, by whom, and where it went are a legal requirement, not a courtesy.[7]

The honest caveat is obvious the moment you state the rule: regulations bind the people who follow them. A heat pump — or air conditioner, or fridge — scrapped by someone who can't be bothered vents its refrigerant to the sky, and for the older high-GWP refrigerants that single act undoes a meaningful slice of the machine's lifetime carbon savings. This is why the "who decommissions it" question deserves the same scrutiny as "who installs it", and it's one more reason the industry's move to low-impact refrigerants like propane matters: it shrinks the stakes of the worst-case handler as well as the best. When we decommission a system, the refrigerant recovery certificate is part of the paperwork you get — if someone quotes you a suspiciously cheap removal, ask them where the gas goes and enjoy the silence.

One wrinkle worth naming, because it caught even us out recently: propane is a hydrocarbon, not a fluorinated gas, so it sits outside the F-gas regime altogether — no mandated recovery, no F-gas paperwork. A grey area, then, but a low-stakes one on the climate ledger: propane's global warming potential is commonly cited at around 3 — recent IPCC assessments put it lower still — against roughly 2,088 for R410A, so an escaped propane charge is climatically a rounding error. What remains is the more traditional concern that propane is flammable — which makes end-of-life recovery a question of safe-handling competence rather than climate law. Regulation hasn't yet caught up with the very refrigerants it encouraged the industry towards; until it does, "who takes it apart" is a safety question, and worth asking with the same seriousness either way.

The scoreboard

The verdict

Nothing in a solar array, a battery or a heat pump is landfill-by-design, and for most of the mass, law and scrap-value already pull in the same direction — the funeral costs are regulated, pre-funded or self-funding. The genuine weak spots are real and worth naming: downcycled glass, unrecovered silicon and silver, exported black mass, burned encapsulant, and the eternal gap between regulation and the people who ignore it. Every one of those is an engineering and economics problem with visible work underway and dated targets you can hold the industry to — which is more than can be said for the combustion alternatives, whose waste products were never collected at all. They went up the flue, every day, by design.