Clean energy #1
Solar panel recycling in the UK - or, has the circular economy train left the station?
When it comes to installing PV panels on roofs, most people aren’t too bothered about what happens to these systems when they degrade and lose efficiency. That’s especially the case with a product that has an anticipated optimal life of 25-30 years, which is the case with solar panels. What matters instead for consumers is what these panels do i.e. their capacity to generate electricity that’s free to use at the point of generation and to turn unused electricity into money through feed-in tariffs.
In this regard, domestic solar installations work more like capital goods or key infrastructure than standard consumer goods. But, just like these things, they too end up deteriorating; to the point that these systems will need replacing.
Currently, there is a looming global problem with what are euphemistically called ‘retired’ or ‘end of life’ (aka “knackered”) PV panels. In a nutshell this is the lack of capacity to deal with them all.
This lack of capacity isn’t unique to PV panels; rather, it runs across all the stuff involved in the green energy transition. This is a function of innovation that remains still largely disconnected from its material consequences. In short, humans tend to focus on making things, not on their capacity to be repaired or undone. I wrote about this in a set of posts last year on repair through objects.
An absence of solutions means that PV panels threaten to become a future waste mountain.
In so doing they remind us that clean energy doesn’t mean an absence of waste. As with all other technologies, ‘green’ ones need options for dealing with them when they come to the end of their useful life.
So what’s the scale of the challenge with PV panels?
The roll out of rooftop domestic and ground-based (solar farm) systems globally, especially since the early 2010s, means that an estimated 4m tonnes of scrap solar in 2030 will grow to > 200 m tonnes by 2050. In the UK domestic solar is now installed on 1.5 million homes. The first wave of that was concentrated in the period 2011-18, and coincided with generous feed-in tariffs. Assuming a 25-year lifespan, these first wave panels will need a solution in place by the mid-2030s.
So where are things currently?
In the UK there is just one industrial scale plant that recycles PV panels – Solar Recycling Solutions, at Dartford, Kent.
Recycling at scale always involves trade-offs, between the costs of processing on the one hand and, on the other, the revenues received from that processing. In turn that’s affected by the volume of input material, ratios of recovered materials to wastes, and - most important of all – the market value of the recovered materials.
Mechanical recycling plants (like the one at Dartford) rely on processing large amounts of material at speed for their profitability. Inevitably, when that’s the focus it’s the input material that matters. That’s framed in terms of the weight/volume of constituent materials. What comes out at the other end of the processing tends to be large amounts of relatively low grade material, which has a mostly low market value. Speed comes at the sacrifice of material quality; there’s the trade-off.
When PV panels are recycled in this way they focus on recovering the most prevalent material/s. Glass comprises 65-75% of the weight of a panel; aluminium, at 10% is the next most significant material. So, what results from this type of processing is large amounts of low-grade crushed glass and aluminium frames. Low-grade glass can be ‘down-cycled’ into a few products (chiefly tiles and road asphalt) but it’s excluded from all high-grade glass making applications.
A very different way of thinking about recycling focuses on the market value of recovered materials. Here processing targets recovering the most valuable materials in any given object, or what recyclers call ‘the nuggets’.
If one thinks about PV panels this way what matters is that 60% of the value is contained in around about 2% of its weight.
We see that value displayed most starkly in spot market price comparisons.
These are the US$ relativities as of 25 May 2025 (which happens to be the day I was researching this post) of the most valuable materials in a PV panel: whereas aluminium was then trading at $2.4/kg, copper was at $9.5/kg and silver at … $1040/kg. You read that right – that’s 3 orders of magnitude higher than the next most valuable material. So, if one thinks about PV panels in terms of the value of recovered materials it’s silver in particular that needs to be targeted in processing.
Realising the loss of value involved in mechanical recycling was one of the reasons why the EU started to embrace the principles of a circular economy in 2015. Whilst the UK spent the subsequent six years embroiled in the machinations of Brexit, in the EU much effort subsequently went in to both applied research and scale-up activity aimed at recovering valuable materials through recycling. Rather than being seen as a means to managing wastes, recycling came to be repositioned as a means to recovering manufacturing grade materials for use within the EU. The fruits of that in relation to PV panel recycling were realised in the form of the first European industrial scale plant, ROSI - Grenoble, which opened in June 2023.
Recycling specialists will typically spend a lot of time talking about their processing technologies, but for me the most interesting things about ROSI are their products and their partnership agreements. These exemplify the principles of circular economy thinking.
ROSI lists its products as: high purity silicon, silver fingers, copper ribbons, furnace-compatible aluminium frames (i.e. suitable for input into electric-arc steel production), and high transparency solar-grade glass cullet (suitable for refabrication into solar panels). In other words, its output is manufacturer-compliant secondary materials. It’s this which underscores ROSI’s partnerships with other manufacturers. Particularly noteworthy here is their connection with Metalor, who take the silver finger output from ROSI and then subject that to further refining to produce manufacturing grade silver alloys, catalysts and coatings, all with a range of applications.
Extracting silver requires hydrometallurgical processing and permits, to manage the processing materials and the wastes of that processing. That’s a very big add-on to capital and processing costs for a recovery-for-recycling plant and its business viability. Partnership deals with existing metal refining firms however, remove those obstacles, because such firms already have the processing infrastructure and permits in place.
Similarly, the partnership established between ROSI and AGC Glass Europe – part of a AGC Group, a global producer of flat glass – shows the value in producing high grade cullet, suitable for use in glass production. That’s a ‘win-win’, because for AGC Europe, that recycled glass counts both as a means to lowering their CO2 emissions and as recycled content in their manufactured goods.
Which brings me to the UK partnership ROSI announced in 2025, with Waste Experts and City Electrical Factors. This is for a UK-wide collection, handling and transportation system for ‘retired’ PV panels.
Collecting sufficient input material to feed an industrial scale operation is the bête noir of the recycling industry. It requires sourcing upwards of 10k tonnes per annum, and making a profit from that activity. That challenge is particularly difficult when that material is geographically dispersed, as is the case with rooftop solar. This is why outsourcing collection to third parties makes perfect sense for recyclers.
But what does this mean for future UK PV panel recycling?
The UK market for retired solar panels is now a battleground between, on the one hand, collectors selling to mechanical recyclers and, on the other, collectors selling to circular economy actors. Since the price paid by collectors is sensitive to the market value of the products of processing, my bet on who’s going to win out here would be on the circular economy actors. If that’s right, the situation that the UK will find itself in down the line is exporting its retired panels for processing in France.
In other words, and to spell this out, it is French capital, which will have captured the value in end-of-life PV panel recycling in the UK. So, and in answer to my question at the top of this post, yes – it appears that, notwithstanding policy commitments to circular economy initiatives in the UK, the circular economy train, at least in relation to PV, may have already left the station.