For all practical purposes, solar energy (along with the wind, waves and tides that it drives) is unending. Or, to put it more starkly, the odds of human beings being around to witness the day when solar energy no longer exists are staggeringly low. The same, of course, cannot be said for the technologies that humans have developed to harvest this energy. Indeed, the term “renewable” is among the greatest PR confidence tricks ever to be played upon an unsuspecting public, since solar panels and wind (and tidal and wave) turbines are very much a product of and dependent upon the fossil carbon economy.
Until now, this inconvenient truth has not been seen as a problem because our attention has been focussed upon the need to lower our dependency on fossil carbon fuels (coal, gas and oil). In developed states like Germany, the UK and some of the states within the USA, wind and solar power have greatly reduced the consumption of coal-generated electricity. However, the impact of so-called renewables on global energy consumption remains negligible; accounting for less than three percent of total energy consumption worldwide.
A bigger problem may, however, be looming as a result of the lack of renewability of the renewable energy technologies themselves. This is because solar panels and wind turbines do not follow the principles of the emerging “circular economy” model in which products are meant to be largely reusable, if not entirely renewable.
According to proponents of the circular economy model such as the Ellen MacArthur Foundation, the old fossil carbon economy is based on a linear process in which raw materials and energy are used to manufacture goods that are used and then discarded:
This approach may have been acceptable a century ago when there were less than two billion humans on the planet and when consumption was largely limited to food and clothing. However, as the population increased, mass consumption took off and the impact of our activities on the environment became increasingly obvious, it became clear that there is no “away” where we can dispose of all of our unwanted waste. The result was the shift to what was optimistically referred to as “recycling.” However, most of what we call recycling today is actually “down-cycling” – converting relatively high value goods into relatively low value materials:
The problem with this approach is that the cost of separating small volumes of high-value materials (such as the gold in electrical circuits) is far higher than the cost of mining and refining them from scratch. As a result, most recycling involves the recovery of large volumes of relatively low value materials like aluminium, steel and PET plastic. The remainder of the waste stream ends up in landfill or, in the case of toxic and hazardous products in special storage facilities.
In a circular economy, products would be designed as far as possible to be reused, bring them closer to what might realistically be called “renewable” – allowing that the second law of thermodynamics traps us into producing some waste irrespective of what we do:
Contrary to the “renewables” label, it turns out that solar panels and wind turbines are anything but. They are dependent upon raw resources and fossil carbon fuels in their manufacture and, until recently, little thought had been put into how to dispose of them at the end of their working lives. Since both wind turbines and solar panels contain hazardous materials, they cannot simply be dumped in landfill. However, their composition makes them – at least for now – unsuited to the down-cycling processes employed by commercial recycling facilities.
While solar panels have more hazardous materials than wind turbines, they may prove to be more amenable to down-cycling, since the process of dismantling a solar panel is at least technically possible. With wind turbines it is a different matter, as Alex Reichmuth at Basler Zeitung notes:
“The German Wind Energy Association estimates that by 2023 around 14,000 MW of installed capacity will lose production, which is more than a quarter of German wind power capacity on land. How many plants actually go off the grid depends on the future electricity price. If this remains as deep as it is today, more plants could be shut down than newly built.
“However, the dismantling of wind turbines is not without its pitfalls. Today, old plants can still be sold with profit to other parts of the world, such as Eastern Europe, Russia or North Africa, where they will continue to be used. But the supply of well-maintained old facilities is rising and should soon surpass demand. Then only the dismantling of plants remains…
“Although the material of steel parts or copper pipes is very good recyclable. However, one problem is the rotor blades, which consist of a mixture of glass and carbon fibers and are glued with polyester resins.”
According to Reichmuth, even incinerating the rotor blades will cause problems because this will block the filters used in waste incineration plants to prevent toxins being discharged into the atmosphere. However, the removal of the concrete and steel bases on which the turbines stand may prove to be the bigger economic headache:
“In a large plant, this base can quickly cover more than 3,000 tons of reinforced concrete and often reach more than twenty meters deep into the ground… The complete removal of the concrete base can quickly cost hundreds of thousands of euros.”
It is this economic issue that is likely to scupper attempts to develop a solar panel recycling industry. In a recent paper in the International Journal of Photoenergy, D’Adamo et. al. conclude that while technically possible, current recycling processes are too expensive to be commercially viable. As Nate Berg at Ensia explains:
“Part of the problem is that solar panels are complicated to recycle. They’re made of many materials, some hazardous, and assembled with adhesives and sealants that make breaking them apart challenging.
“’The longevity of these panels, the way they’re put together and how they make them make it inherently difficult to, to use a term, de-manufacture,’ says Mark Robards, director of special projects for ECS Refining, one of the largest electronics recyclers in the U.S. The panels are torn apart mechanically and broken down with acids to separate out the crystalline silicon, the semiconducting material used by most photovoltaic manufacturers. Heat systems are used to burn up the adhesives that bind them to their armatures, and acidic hydro-metallurgical systems are used to separate precious metals.
“Robards says nearly 75 percent of the material that gets separated out is glass, which is easy to recycle into new products but also has a very low resale value…”
Ironically, manufacturers’ efforts to drive down the price of solar panels make recycling them even more difficult by reducing the amount of expensive materials like silver and copper for which there is demand in recycling.
In Europe, regulations for the disposal of electrical waste were amended in 2012 to incorporate solar panels. This means that the cost of disposing used solar panels rests with the manufacturer. No such legislation exists elsewhere. Nor is it clear whether those costs will be absorbed by the manufacturer or passed on to consumers.
Since only the oldest solar panels and wind turbines have to be disposed of at present, it might be that someone will figure out how to streamline the down-cycling process. As far more systems come to the end of their life in the next decade, volume may help drive down costs. However, we cannot bank on this. The energy and materials required to dismantle these technologies may well prove more expensive than the value of the recovered materials. As Kelly Pickerel at Solar Power World concedes:
“System owners recycle their panels in Europe because they are required to. Panel recycling in an unregulated market (like the United States) will only work if there is value in the product. The International Renewable Energy Agency (IRENA) detailed solar panel compositions in a 2016 report and found that c-Si modules contained about 76% glass, 10% polymer (encapsulant and backsheet), 8% aluminum (mostly the frame), 5% silicon, 1% copper and less than 0.1% of silver, tin and lead. As new technologies are adopted, the percentage of glass is expected to increase while aluminum and polymers will decrease, most likely because of dual-glass bifacial designs and frameless models.
“CIGS thin-film modules are composed of 89% glass, 7% aluminum and 4% polymers. The small percentages of semiconductors and other metals include copper, indium, gallium and selenium. CdTe thin-film is about 97% glass and 3% polymer, with other metals including nickel, zinc, tin and cadmium telluride.
“There’s just not a large amount of money-making salvageable parts on any type of solar panel. That’s why regulations have made such a difference in Europe.”
Ultimately, even down-cycling these supposedly “renewable” technologies will require state intervention. Or, to put it another way, the public – either as consumers or taxpayers – are going to have to pick up the tab in the same way as they are currently subsidising fossil carbon fuels and nuclear. The question that the proponents of these technologies dare not ask, is how far electorates are prepared to put up with these increasing costs before they turn to politicians out of the Donald Trump/ Malcolm Turnbull stable who promise the cheapest energy irrespective of its environmental impact.
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