Farm waste to solar power? Clean energy just got cleaner

Imagine powering your home with solar panels made from minerals and leftover crop materials. That could become a reality—scientists in Singapore have developed a solar cell using the mineral perovskite and an organic-based polymer, and it’s showing promising results.

Their recently developed, sustainably-made solar cell can maintain an energy efficiency of 21.39%, according to the researchers’ findings published in early February. It’s still far less than the 34% efficiency of traditional solar panels, which are typically made out of silicon, but it’s a big step in the right direction. Switching to organic-based polymers could also lower the cost of solar, as silicon is becoming increasingly scarce and therefore more expensive.

Solar power is an efficient clean energy source, using the sun’s rays to generate electricity rather than burning harmful fossil fuels. However, the process of manufacturing solar panels, and the materials needed—like silicon—aren’t as eco-friendly as you might think. (More on this in the next section.)

Scientists at the Nanyang Technological University (NTU) in Singapore and Polytechnique Hauts-de-France have been working together to solve this issue. They’ve been developing hybrid perovskite solar cells (HPSCs), which are cheaper to produce and easier to manufacture than standard silicon solar cells.

Using perovskite for solar technology isn’t new—the first perovskite solar cell was developed in 2009. However, the problem is that perovskite solar cells are typically created with a photoactive layer made from petroleum-based polymers, which raises sustainability concerns because petroleum is a fossil fuel and a major contributor to greenhouse gas emissions.

The researchers at NTU discovered they could instead use a biomass base made from furan—a chemical compound that can be derived from crop waste, like corn cobs or sugarcane stalks. It’s not only cleaner than petroleum; it’s also more affordable and easier to mass-produce.

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Solar energy is a renewable, carbon-free resource that’s been tapped as a solution to slow the threat of climate change. That said, the panels themselves, and the manufacturing process, aren’t the most sustainable.

Solar panels are made from silicon, as well as materials like metals and glass that require a lot of energy to create. Manufacturing photovoltaic (PV) cells also requires handling hazardous chemicals, so great care and resources are needed to avoid releasing toxins into the environment, especially at the end of the panels' lifespan.

Speaking of: solar panel recycling is another hurdle. A 2016 study by the International Renewable Energy Agency (IRENA) estimated that solar panel waste would reach 78 million tonnes globally by 2050 if PV recycling didn’t improve. Fortunately, there have been developments in solar panel recycling. It’s now either available or in the works in states like California, Texas, New Jersey, and Washington State.

Perovskite solar panels with plant-based polymers would likely be easier and more cost-effective to recycle, as their materials are organic and biodegradable.

These eco-friendly solar panels are stacking up pretty well—the scientists revealed they’ve reached an efficiency of 21.39%. While impressive, it falls short of the 34% achieved by traditional silicon solar cells, so we likely won’t see these waste-based solar panels hit the market anytime soon. But it’s a notable start, and reason enough for these scientists to continue working on silicon solar cell alternatives.

They also said their recent discovery is a “promising pathway for more efficient, stable, and potentially more sustainable” solar panels—which means we may see solar panels created from all kinds of sustainable materials in the future.