Recycling solar panels

Copyright: rukanoga / 123RF Stock Photo
solar battery and symbol of recycle

Today, you see commercial solar farms big and small all over Europe, according to the latest figures Europe produced 98 GW in 2017 98 GW in 2017;[i] this is well up on the 13.4 GW in 2010.[ii] The growth in the usage of solar power has come as the result of proactive energy policies, concern for the environment and innovations that have reduced the cost of the technology and energy produced. W.R. Williams CEO Altresco Energy says, “Solar cells used to cost $100/w, now that’s down to $0.35. per watt of capacity. That’s the cost of the equipment, not the power produced.”

It is not surprising that investors, fund managers and utilies, such as Octopus Investments, Enerparc AG, Foresight Group, Capital Stage AG, CEE-group, EDF Energies Nouvelles, NextEnergy Solar Fund, IB Vogt, Bluefield Solar Income Fund Ltd and Luxcara are Europe’s top ten investors in solar farms.[i]

Nowadays, the output from a solar panel can cost as little as $0.50 a watt. In addition, the cost of solar panels has dropped by 10 percent a year. For instance, a small  4 kWh system, which would have cost around £10-12,000 a few years ago will more likely set you back £6,500 today. [iii]It is not surprising that the increasing popularity of this generating technology, that has resulted in it becoming commonplace powering homes, factories, shopping centres, ships and satellites. For examples of European solar farms in operation and who owns and operates them see Table 1.


List of some of the solar farms in Europe

ProjectCame on lineGenerating CapacityRefurbishedOriginal operatorCurrent operator
Pellworm, Germany1983Was 300 KW, now 600 KW2015E.ON Hanse AGE.ON Hanse AG
Toledo-PV, Spain19941 MW2016ENF solarENF solar
Pocking Solar Park, Germany2006.10 MWUnknownShellShell
Serpa solar power plant, Portugal200711 MWUnknownGE Energy Financial Services, Powerlight Corporation, CataventoGE Energy Financial Services, Powerlight Corporation, Catavento
Florina Solar Power Plant, Greece20094 MWUnknownAES CorporationAES Corporation
Ralsko Solar Park, Czech Republic201014 MWUnknownCEZ GroupCEZ Group
Casale solar park, Italy20103.3 MWUnknownStatkraftEurowood s.p.a. and Blue Stream Resources s.r.l.
Rhosygilwen Solar Farm20111 MWUnknownWestern SolarWestern Solar
Curbans Solar Park, France201133 MWUnknownEngieEngie
Westmill Solar Co-operative, UK20125 MW.UnknownWestmill Solar Co-operativeWestmill Solar Co-operative
Trumau aolar Park, Austria2013300 kWUnknownWien EnergieWien Energie
Guntramsdorf photovoltaic plant, Austria20152 MWUnknownWien EnergieWien Energie
Cestas Solar Farm,France2015300 MWUnknownNeonNeon
Onnens Sor Farm, Switzerland20168.3 MWUnknownSoleolAventron, UBS Clean Energy Infrastructure Switzerland and Swiss Solar City
Bann Road Solar Farm, Northern Ireland, UK201714 MWUnknownENGIEENGIE
Solar park “Lange Runde”, Holland201714 MWUnknownStatkraftStatkraft

Source: various sources

Operating lifespan

As to how long such solar cells last, some manufacturers are suggesting perhaps between 25 and 40 years. However, it would be better to say, how long will solar cells were commercially viable, current thinking suggests depending on the degradation rate between 20 and 25 years.

Like most things, wear and tear over the years affects the efficiency of the solar cells. Such factors that can affect the efficiency of a solar cell include:

  • The quality of your panels’ materials and design.
  • The weather they’re exposed to (e.g., high winds and humidity, scorching rooftop temperatures, annual freeze/thaw cycles), the faster they may degrade.
  • Potential damage caused by trees and bushes rubbing against panels.
  • The issue of dust, for instance, in desert-like conditions damage caused by dust can have a significant impact on operating efficiency.

So as a rule of thumb panels generally experience short-term degradation of between 0.5 and 3%. Subsequently, solar panels experience declines of between 0.8 to 0.9 percent per year.

As a guide, according to a research article Compendium of photovoltaic degradation rate published in 2016 in Progress in Photo Photovoltaic Journal. The article suggests that, if such as, in a panel’s first year of operation it degraded by 2%, this would mean that it would have an operating efficiency of 98% in year two. Subsequently, from this point, assuming it degrades and 0.8% per year, afterwards, it is assumed that they will work at 78.8% efficiency in year 25.


What are the estimated maintenance or replacement costs for a solar energy system?

Another question operators should be asking themselves is how long the inverter will last. Since the inverter converts the DC power from the panel to AC for export to the grid. The average inverter warranty ranges from between 5 and 10 years and unlike solar panels, will not just slowly get more inefficient, but will instead just stop functioning. Replacing an inverter can cost up to £5000.

However, while that’s usually the case with a central inverter (which handles the output of all the panels), a newer type, the so-called ‘micro-inverters’, are installed or included with each solar panel, and are said to have a much longer lifespan (up to 25 years),[iv] and could last for decades as well.

Solar Panel End of Life

Once such a plant comes to the end of its planned working life cycle, the question is what to do with the site and the waste. For operators, there are various decommissioning options available including total removal of all installations, selling components for scrap and recycling before returning it to a green field. Such an option is said to cost for a 2 MW solar installation in Massachusetts, about $98,000 after 20 years. [v]As for other operators the option is to upgrade the installation, as has been done at some of Europe’s oldest solar plants, for instance at 600 KW  plant Pellworm, built in 1983 in Germany and Toledo 1 MW plant in Spain built in 1994.

The rest of this article will look at the issue of how solar panel waste is recycled.

Solar Panel waste

In many countries, the problem of solar panel waste disposal is a general waste problem, but in Europe, solar panels are defined as e-waste in the Waste Electrical and Electronic Equipment (WEEE) Directive.[vi]  As a result, the law binds solar cells manufacturers to fulfil specific legal requirements and recycling standards to make sure that solar panels do not become a burden to the environment. That is when technologies to recycle solar panels started emerging. Solar cell makers have worked with member states governments to find solutions for solving this waste problem.

As a result, in many European [vii] and American [viii] states there are specialist solar panel recycling facilities, In France, for instance, a new solar panel recycling plant opened at Rousset in southern France. This new factory owned by French water and waste group Veolia will initially recycle 1,300 tonnes of solar panels in 2018 – that’s nearly all the solar panel waste that will be produced in France in 2028. Subsequently, it is planned to increase processing capacity recycling to 4000 tons by 2022. In a 2016 study on solar panel recycling, the International Renewable Energy Agency (IRENA) said that in the long-term, building dedicated PV panel recycling plants makes sense. It estimates that recovered materials could be worth $450 million by 2030 and exceed $15 billion by 2050.

Two main ways of recycling solar waste

There are two main options available for solar panel recycling; these are silicon-based and thin-film-based. The recycling process that is adopted will depend on the type of solar panel being recycled. Recent research suggests that re-cycled solar panels can reach 96% recycling efficiency. A good example of this is the refurbishment of the solar plant at Pellworm, Germany.

At present silicon-based panels are the most commonly used, though there is an increasing amount of panels based on thin film based technology.

Both types of panel technology—silicon-based and thin-film based—can be recycled using distinct industrial processes.


Silicon Based Solar Panel Recycling

To recycle a silicon-based solar panel, it means taking apart the actual product in order to separate the aluminium and glass parts. A typical crystalline silicon solar panel is made up of 65-75 percent glass, 10-15 percent aluminium for the frame, 10 percent plastic, and just 3-5 percent silicon. In fact, 95% of the glass content can be reused, whilst all metal parts can also be often reused including the cell frames. As for the rest of the materials they can be treated at 500°C in a thermal processing unit in order to ease up the binding between the cell elements. The extreme heat removes any plastic which evaporates, leaving just the solar cells ready for further processing.

Once the thermal treatment is completed, the green hardware is separated. About 80% of this can be reused, whilst the rest can be further processed. Silicon particles called wafers are etched away using acid. The broken wafers are melted to be used again for manufacturing of new silicon modules resulting in an 85% recycling rate of the silicon material.

Thin-Film Based Solar Panel Recycling utilities

CIGS thin-film panels are made up of 89% glass, 7% aluminium 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.[ix]

In the case of thin film based panels, this first step involves putting them in a shredder. Subsequently, a hammer mill is used to make sure that all particles are no bigger than 5 mm, which is the size where the lamination keeping the inside materials together fractures, and hence can be removed. Unlike silicon-based solar panels, the remaining content consists of both solid and liquid material is. In order to separate these a rotating screw is used, which basically keep the solid parts rotating inside a tube, whilst the liquid drips into a container.

The liquids go through a precipitation and de-watering process to make sure purity of the contents. Resulting contents then goes through metal processing to completely separate different semi-conductor resources. On average, about 95% of the semiconductor materials are reused, though this can vary depending on the design of the panels used.

As for solid contents which are contaminated with so-called interlayer materials, which are lighter in mass and can be removed through a vibrating surface. Finally, the resultant materials go through a rinsing process. What is left behind is pure glass, enabling 90% of the glass elements for easy re-manufacture.

So one thing is certain, recycling and refurbishing can successfully extend the operating lifespan of solar plant installations.











[i] to the latest figures solar power

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