How much waste do solar panels and wind turbines produce?

Solar and wind produce less waste than coal; but they can reduce waste even further

You might have seen the following image from a recent paper from Heather Mirletz and colleagues, published in Nature Physics.¹ It has been shared a lot in my circles on social media.

The authors estimate that solar waste in 2050 will be very small compared to other waste flows.

Between 2016 and 2050, solar waste generation would amount to 54 to 160 million tonnes: less than one-tenth of e-waste streams, and at least 99.6% less than coal ash and municipal waste.

This is important context given mounting fears about huge quantities of dumped panels.

This work was focused on solar, but other studies have looked at projections for wind power. A study by Pu Liu and Clare Barlow estimated that global cumulative turbine waste by 2050 would be around 42 million tonnes – in a similar range to solar power.²

One small (tangential) nitpick of the chart above: I’m not sure why the waste flows are shown as cubes. The comparisons are on the basis of mass, not volume. It might make sense if the materials had the same density: that would allow us to visualise the differences in volume in a landfill, for example.

But the units are on the basis of mass so it seems more appropriate to have it as a bar chart, like the one below. It also shows the differences more clearly.

A few people emailed to ask whether I could look at these waste comparisons not as cumulative totals, but per unit of electricity. And to include wind and nuclear power. That’s what I’ll do in this post.

The overall message is similar: less waste is produced from solar, wind, and nuclear than coal. And they are very small compared to other waste streams such as plastics or municipal waste.

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Waste generation per unit of electricity

Credit to David Osmond, whose Tweet I got the inspiration for the following calculations. I have some different assumptions, but his approach was the springboard. He’s a great follow on Twitter (or X) if you’re interested in renewables.

I have calculated how much waste would be generated per megawatt-hour of electricity generation for solar, wind, nuclear, and coal. See the footnote for a walk-through of where these numbers come from (feel free to critique!).³

The results are shown in the chart. Coal generates 50 times as much as solar; more than 500 times as much as wind; and more than 2700-times as much as nuclear.

Most of the waste from coal is in the form of coal ash. For solar, it’s the panels at the end-of-life. The blades for wind. Unprocessed uranium and spent fuel for nuclear.

Moving from coal to low-carbon energy will reduce waste; not increase it. People often share pictures of piles of used turbine blades or panels. But they don’t show massive heaps of coal ash that are generated elsewhere.

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How much waste would the average person generate over 25 years?

Another way to do this comparison – which lets us compare these streams to other types of waste – is to look at how much waste the average person would generate over the next 25 years.

I’ve picked 25 years because that’s the average lifetime of a wind turbine. Solar panels can have a slightly longer lifespan of around 30 to 35 years.

I’m going to assume that I’m like the average person in the UK. I have calculated how much waste would be generated from different electricity sources if I got all of my electricity from that source. So, imagine that I got all of my electricity from solar PV over the next 25 years. Or wind, or coal, or nuclear. That’s unrealistic because we’ll have a range of sources in the electricity mix, but it’s a good stress-test of how the different technologies stack up.

The UK generates 4,812 kilowatt-hours of electricity per person each year. That’s around 120 MWh over 25 years [for now we’ll assume that electricity generation stays where it is].

That means I’d generate: 10 tonnes of coal ash; 201 kilograms of solar PV waste; 19 kilograms of wind blades; or 4 kilograms of nuclear waste.

This is shown in the chart.

I’ve also included other forms of waste that I’d generate over the next 25 years. This data comes from the World Bank; Jambeck et al. (2015); and the OECD.⁴

Waste from solar PV, wind, or nuclear is pretty small compared to other streams. Coal ash, however, is big – of a similar magnitude to total municipal waste.

A fair point is average electricity consumption in the UK will increase in the next few decades as we electrify transport, heating, and other industries. That’s fine: we can just double the coal, solar, wind, or nuclear figures. That won’t change the headline results.

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It’s not just about quantity: what about the toxicity?

It’s not just the amount of waste that’s generated that matters, but the toxicity of it too. A kilogram of arsenic or mercury is not the same as a kilogram of cotton in municipal waste.

So, how concerned should we be about the toxicity of waste from solar or wind?

Let’s start with wind. 

80% to 85% of wind turbine components can be recycled; it’s the blades that can’t be (at least not easily). They’re made from composite materials – primarily fibreglass, mixed with others such as carbon fibre and resins to reduce their weight (while maintaining their sturdiness). This makes them harder to recycle because the individual components need to be separated.

In the US and Europe, blades are categorised as non-hazardous waste, and can be sent to landfill. The risks to human health are extremely low. There are some concerns about microplastics; a reasonable concern, however, wind power is a small contributor to the total amount of microplastics out there (look at the plastics bar in the previous chart…).

Of course, we should focus on making the final 20% of wind turbines recyclable; not just to prevent landfilling, but to make resource use more circular. There is a bunch of research and development in this area. Siemens has launched its RecycleableBlade. Many people have called for Europe-wide bans on blade landfilling this decade.

What about solar?

Mirletz et al. (2023) discussed the toxicity of solar waste in their paper (the one at the very top of this post). They highlight that US state health departments list a range of potential toxins in solar panels: arsenic, gallium, germanium, and hexavalent chromium.

Except, most panels are crystalline silicon or cadmium telluride (CdTe), which don’t have arsenic, gallium, germanium, or hexavalent chromium in them. More information on where some of these claims might come from is in the footnote.⁵

The only health concern from solar panels is the small amounts of lead in silicon panels and trace amounts of cadmium in CdTe ones. The International Energy Agency flags these as the only potential human health risk too.⁶ 

Cadmium is present in CdTe panels in very low concentrations – only around 0.1% by weight – and they are currently collected, with the cadmium used in new modules.

I’ve done quite a lot of work on lead pollution on Our World in Data, and think it is an underrated global problem (it’s mostly concentrated in low- and middle-income countries today). Although it’s present in low concentrations in silicon panels, this is a risk that needs to be appropriately managed. Moving to lead-free components would be a big step forward (people are working on it).

Most people are unaware of coal ash toxicity.

The potential risks of solar and waste need to be addressed. But it’s interesting that concerns about waste are mostly appearing now – following centuries of fossil fuel production, which generates toxic waste.

Coal ash contains elements such as mercury, arsenic, lead, cadmium, and chromium.

From the US CDC’s Agency for Toxic Substances and Disease Registry:

“Coal ash can contain particulates (a mixture of solid particles and liquid droplets found in the air), volatile and semi-volatile organic compounds, and heavy metals.

These chemical compounds can cause skin irritation (dermatitis). Inhalation (breathing in) of these compounds can cause respiratory irritation and irritation of the eyes, nose, and throat. Ingestion (eating or swallowing) of these compounds can cause nausea, vomiting, and diarrhea. Some of the compounds found in coal ash can cause cancer after continued long-term ingestion and inhalation.”

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Conclusion

I think it’s unlikely that we’ll have millions of tonnes of solar panels and turbines going to landfills. At least, we should ensure that this isn’t the future we’re building. One of the many upsides of renewable energy is that it’s much more ‘circular’ than fossil fuels. Build it and the fuel is resource-free for decades.

We need to make sure that this circularity is continued at the end of its life. 

But even in the worst case, moving away from coal power to renewables (or nuclear) would significantly reduce the amount of waste generated. Not to mention that fossil fuels generate other forms of ‘waste’ that are terrible for human health. Millions die every year from local air pollution. And more will die in the future as a result of climate change.

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p.s: I expect many of you have been screaming for me to talk more about the management of nuclear waste. That’s too big of a topic to cover in this post – I will need to cover it another time to give it proper space.

1. Mirletz, H., Hieslmair, H., Ovaitt, S., Curtis, T. L., & Barnes, T. M. (2023). Unfounded concerns about photovoltaic module toxicity and waste are slowing decarbonization. Nature Physics, 1-3.

2. Liu, P., & Barlow, C. Y. (2017). Wind turbine blade waste in 2050. Waste Management, 62, 229-240.

3. Solar PV:

Take a standard 400 W solar panel, which weighs around 22 kilograms. We’ll assume that all of that mass goes to waste (i.e. there is zero recycling of materials, which is very conservative).

If it had a 15% capacity factor, it’d produce 0.53 MWh per year (400 * 365 * 24 * 15% / 1,000,000).

If we assume it has a lifetime of 25 years (which is on the low side), then it’d produce 13 MWh over its lifespan [0.53 * 25].

That gives us 1.67 kilograms of waste per MWh [22 kg / 13 MWh].

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Wind:

Take a 5 MW wind turbine. A lot of the electrical components can be recycled, so it’s the blades that will primarily end up as waste. The blades will weigh around 60,000 kilograms.

If it had a 35% capacity factor, it’d produce 15,330 MWh per year (5 * 365 * 24 * 35%).

If we assume it has a lifetime of 25 years, then it’d produce 383,250 MWh over its lifespan.

That gives us 0.16 kilograms of waste per MWh [60,000 kg / 383,250 MWh].

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Coal ash:

Around 89 kilograms of ash is produced per MWh.

In the US, in 2018, around 102.3 million tonnes of ash were produced. The US produced 1,145,962,000 MWh of electricity from coal. That give sus 89 kilograms per MWh.

This figure is similar to the 84 kilograms of coal per MWh reported by CleanTechnica. 

David Osmond also estimated 84 kilograms of coal ash per MWh.

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Nuclear:

A one gigawatt (GW) plant produces around 250 tonnes of waste per year: 35 tonnes in the form of spent fuel, and 215 in the form of depleted uranium.

If we assume a 93% capacity factor (the average in the US) then a one-gigawatt plant produces 8,146,800 MWh per year [1000 MW * 23 * 365 * 93%].

That gives 0.031 kilograms of waste per MWh [250,000 kg / 8,146,800 MWh].

4. Municipal waste: Data comes from the World Bank’s What a Waste 2.0: A Global Snapshot of Solid Waste Management to 2050 report. Average waste generation in the United Kingdom is around 1.33 kilograms per person per day.

That’s 485 kilograms per year. And 12,125 kilograms over 25 years.

Kaza, Silpa; Yao, Lisa C.; Bhada-Tata, Perinaz; Van Woerden, Frank. 2018. What a Waste 2.0: A Global Snapshot of Solid Waste Management to 2050. Urban Development;. Washington, DC: World Bank. http://hdl.handle.net/10986/30317

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Plastic waste: Data comes from a study by Jenna Jambeck et al. (2015). 

The average person in the UK produces around 77 kilograms of plastic waste per year. That’s equal to 1916 kilograms over 25 years.

Jambeck, J. R., Geyer, R., Wilcox, C., Siegler, T. R., Perryman, M., Andrady, A., ... & Law, K. L. (2015). Plastic waste inputs from land into the ocean. Science, 347(6223), 768-771.

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E-waste: Data comes from an OECD report.

The average person in the UK produces 24 kilograms per year.

That’s 600 kilograms over 25 years.

5. In the paper, they note that:

• Arsenic and gallium are only used in high-efficiency modules in the aerospace industry.

• Gallium was only ever used once, and not in modules that were mass-produced.

• Chromium was only ever used in laboratory cells in the 1970s.

6. Sinha, P., Heath, G., Wade, A. & Komoto, K. Human Health Risk Assessment Methods for PV, Part 3: Module Disposal Risks (International Energy Agency PVPS Task 12, 2020).