Solar power. Who doesn’t like it? It’s a clean, green, beautiful, renewable energy source that can be found almost everywhere the Sun shines. Solar energy plays an important role in the global effort to reduce our reliance on non-renewable energy sources such as fossil fuels, with the primary goal of preserving our home planet.

Solar energy appears to be more promising than ever on paper. It has grown to become the world’s cheapest form of electricity for companies to build, according to the International Energy Agency, and the fastest growing source of electricity in recent years. Solar installations have increased by more than 30% annually on average over the last decade, leading to cost reductions of more than 90%.

Even better, there is some progress being made for solar panels to be more effective in the darker winter months; a hybrid structure combining existing solar panels with this new kind of “night solar panel” might be built (a.k.a. “anti-solar panels”).

Isn’t this it? This is all we need, right?

Solar power isn’t completely apples and sunflowers – there is a dark side that is seldom talked about. There are numerous questions that arise when we talk about the shadow of solar panels – is solar power efficient enough? Would the panels function even if the weather is cloudy or rainy? Isn’t it expensive? All these myths and misconceptions have been busted. And yet, the ultimate question remains: what happens to all these solar panels after they die?

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First off, there’s the panel as it is.

Solar panels are of three primary forms: monocrystalline, polycrystalline and thin-film. The most crucial component of any solar panel is the solar cells. A single solar panel is constructed using multiple solar cells. When sunlight hits these solar cells – also called photovoltaic (or PV) cells – that light gets converted into electricity. These cells are a component of the technology that converts sunlight to energy by the photovoltaic effect.

Most solar panels use crystalline silicon solar cells made of silicon atoms that are connected to each other to form a crystal lattice. Crystalline silicon cells are made up of silicon, phosphorous and boron layers (although there are numerous types of PV cells). Once created, the cells are set out in a grid arrangement. Because there are several size possibilities, the number of these cells required is generally determined by the size of the panel being built.

After the cells are set out, the panel is sealed and coated with an anti-reflective glass to safeguard the cells within. This glass reflects about 2% of the incoming sunlight while allowing the remainder to reach the cells. This panel is then sealed and fitted into a sturdy steel frame, which is made to avoid deformation and contains a drainage hole to prevent water from collecting on the panel, which might lower the panel’s efficiency. The rear of the panel is further sealed to shield it from damage.

Further, each individual solar cell is made up of two types of semiconductors: p-type (positive) and n-type (negative) silicon layers. The n-type silicon layer has additional electrons that can move around freely, whereas the p-type silicon layer has electron vacancies known as holes. When the layers are brought together, electrons begin to move from the n-type to the p-type, forming a unique junction that generates electric potential in the material.

When sunlight strikes this connection, it can knock an electron loose, leaving a hole behind. The free electrons begin to congregate near the pole as more electrons fill the newly formed holes.

So what’s the problem?

Solar energy is a rapidly expanding marketplace that should benefit the environment. Solar panels can last for decades if they are properly cleaned and maintained. There is, however, a catch. What happens to these panels after they are decommissioned? They go straight to the landfill.

Solar panels have a productive lifetime of around 25-30 years. But a solar panel will not completely expire after 25-30 years; rather, its output will significantly drop. A report published by the International Renewable Energy Agency highlights that “large amounts of annual (solar panel) waste are anticipated by the early 2030s” and could reach 78 million tonnes by the year 2050. Annually, about 6 million metric tonnes of new solar e-waste will be globally generated.

Because of increased efficiency and lower costs, many users are likely to replace their current panels years before the predicted 30 years of useful life. Solar panel waste could amount to roughly 315,000 metric tons by 2050.

The effect of these solar panels on the landfill is significant. Heavy metals in solar panels, such as lead and cadmium, have been proven in studies to seep out of the cells, enter groundwater and harm plants, alter soil fertility, and affect our livelihood. These metals have also been linked to health problems in humans.

Also, most solar recycling facilities simply extract the valuable silver and copper from the cells before burning the contaminated glass and plastic casings in cement furnaces. Solar companies prefer to dump the dead panels in landfills or ship them to third-world nations because the process is costly and time-consuming.

Also read: For Developing Countries, More Solar Power – and More Lead Contamination

The major users of solar panels are currently China and the United States, but only Europe has taken steps to hold producers accountable for their waste.

Veolia, a French waste management business, has opened Europe’s first solar cell recycling facility. Solar companies are required by the European Union to collect and recycle their panels, with the cost of recycling included in the selling price. With only a slight increase in the price of solar panels for consumers, the waste and environmental impact of the panels are reduced. The major goal should be for businesses to employ such solutions rather than choosing the cheaper option of dumping panels in landfills.

As we turn our backs to fossil fuels, solar energy will play a critical part in our future. That being the case, we can anticipate expanded solar panel production in the coming decades and enormous amounts of hazardous waste. It’s a tough decision to compare the merits and demerits of solar panels.

But we must think: are we solving a problem just to create another? The global society must come up with a mutual solution or harnessing light energy may leave us in a darker place.

Mahashri Ranjith Kumar is a climate change activist in Bengaluru. She has been involved with multiple international organisations, such as Youth STEM 2030 and the International Network of Women Engineers and Scientists. She was also a panelist at the COP26 climate talks.

Vasudevan Mukunth, editor: mukunth@thewire.in

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