What makes solar panels sustainable

As a way of converting the sun's energy into electrical energy, solar panels make use of the single most sustainable resource on the planet - the light of the sun. According to the United Nations , sustainability means "development that meets the needs of the present without compromising the ability of future generations to meet their own needs.

Most experts agree that the sun is the most important source of renewable energy. Solar energy is considered a renewable resource, as opposed to non-renewable energy sources , such as fossil fuels, which are finite. There is more than enough solar power to provide for all the energy needs of the planet, even if the Earth's population continues to grow and consume more energy, making it an important component of effort to combat climate change.

A study published in Scientific American found that in 40 minutes the amount of energy contained in the light of the sun that reaches the Earth is equivalent to the amount of electrical energy used on the planet in a year's time. Fossil fuels cause pollution as they are consumed, while solar energy does not, which is another way that it embodies the principles of sustainability. Solar panels sit idly on rooftops or in large solar arrays, creating no waste products, noise or any other outputs - just clean electrical energy.

While yes, solar energy itself is sustainable, harnessing that energy is not completely free of any disadvantages and some of these relate to its degree of sustainability. However, these disadvantages pale in comparison to the positive potential of solar power as a sustainable energy source.

A major reason why solar energy has not become more widespread is that it is not yet economically sustainable. The up front cost of installing solar panels eventually pays for itself because they produce energy for free once they are up and running, but the ratio of costs to energy produced has remained too high for the average homeowner to afford panels, as well as for large scale applications.

Solar technology continues to advance, however, so it is expected that at some point solar energy will become more cost effective than non-renewable energy sources that, by nature, become more expensive as their availability declines. While the sun is in an inherently sustainable energy source, some of the materials needed to make solar panels are not sustainable. Solar panels are built with rare minerals, such as selenium, that will eventually be exhausted if solar panel manufacturers continue to extract them at an accelerating pace.

On the other hand, there's not a big market for it right now. Because recycling is limited, Mulvaney said, those recoverable metals could go to waste: "Companies that are reporting on a quarterly basis, surviving on razor-thin margins—they're not thinking 20, 30 years down the road, where the scarcity issue might actually enter the conversation. The silicon used to make the vast majority of today's photovoltaic cells is abundant, but a "silicon-based solar cell requires a lot of energy input in its manufacturing process," said Northwestern's You.

The source of that energy, which is often coal, he added, determines how large the cell's carbon footprint is. The SVTC said it's leading an effort to develop a first ever sustainability standard for solar panels, similar to the U. That effort will get under way as new solar panel factories come online in the U. It remains to be seen whether solar companies will face enough external pressure to drive significant change in a business that, from a power-generation standpoint, already has plenty of environmental credibility.

But there is optimism that as the industry matures, solar companies will adopt stronger sustainability measures. In just the five years since the SVTC began its scorecard survey, Mulvaney said, it has seen a change. The story is part of a special series that explores energy issues. For more, visit The Great Energy Challenge. All rights reserved. Share Tweet Email. Why it's so hard to treat pain in infants. This wild African cat has adapted to life in a big city.

Animals Wild Cities This wild African cat has adapted to life in a big city Caracals have learned to hunt around the urban edges of Cape Town, though the predator faces many threats, such as getting hit by cars.

India bets its energy future on solar—in ways both small and big. Environment Planet Possible India bets its energy future on solar—in ways both small and big Grassroots efforts are bringing solar panels to rural villages without electricity, while massive solar arrays are being built across the country. Go Further. Animals Climate change is shrinking many Amazonian birds. Animals Wild Cities This wild African cat has adapted to life in a big city. Animals This frog mysteriously re-evolved a full set of teeth.

Animals Wild Cities Wild parakeets have taken a liking to London. Solar panels provide the largest and cheapest source of renewable energy. But there is still room to reduce the high emissions created when building solar power infrastructure.

Despite its status as a renewable energy stalwart, solar power infrastructure can still produce high carbon emissions. Solar panels have become synonymous with green energy, yet the mining and processing of silicon, glass and aluminum necessary to make them requires energy. And it's not always clean. But depending on the panel and installation site , photovoltaics can generate as much energy as was used in their production within five to 25 months.

Here are four essentials of solar panel production, design and longevity that will influence their sustainability. The first grid-connected photovoltaic solar panels were installed in Germany and other countries in the s. Some panels are still in operation decades later, while new models are sometimes now sold with a year warranty. But panels can last even longer when robust glass is incorporated on the back, which is common in photovoltaic cell manufacturing today.

The longer the service life of solar systems, the lower the CO2 emissions, and the cost of generating renewable power from the sun. Solar panels have a very simple structure. They consist of a translucent special glass pane, a translucent plastic film EVA underneath, a silicon cell only 0. Behind the cell is another plastic film, and then on the back a special protective film or glass.

Everything is firmly interconnected, usually with an aluminum frame with a seal. If the glass on the front side breaks due to extreme hail, a panel should be replaced to prevent moisture from getting inside and reducing the system's performance — a simple glass replacement is not possible here.

After years in operation, the seal and film on the back of the modules can become porous. An adhesive paste can be used to reseal the film against moisture intrusion.

If, over time, the electrical cables become porous, or diodes in the junction box fail, they can usually be replaced without complications. According to the German Environment Agency UBA , there is no danger of pollutants leaking from undamaged or broken panels. However, most models do contain small quantities of environmentally harmful substances. In the case of the widely used crystalline solar modules approx.

Some manufacturers do not use toxic lead at all. In so-called thin-film modules approx. However, manufacturers of these panels have their own take-back system and recover cadmium and lead, as well as non-toxic metals silver, copper and tellurium.

While discarded modules have to be disposed of properly in Europe, most other countries don't yet have such regulations. The standards are intended to prevent solar panels from rotting in the natural environment and eventually leaching pollutants. In addition, solar panels contain valuable raw materials that can be recycled.

When that doesn't happen, the aluminum frames, cables and junction boxes are removed and the crystalline panels are shredded while glass, metals and foils are separated using various techniques. Metals and lead are separated and reused while glass fragments are generally processed into thermal insulation material known as glass wool. The plastic foils are incinerated in plants with filters to generate energy. However, environmental and raw materials experts still see a lot of room for improvement in recycling.

They would like to see high-grade solar glass from old modules reused for new modules instead of for low-quality insulation materials as is currently the case. Likewise, high-purity silicon from old modules could be used for new solar cells. Until now, it has only been used as an additive in aluminum production. For this reason, too, the globally booming photovoltaic industry is an important future market for the recycling industry — especially as millions of panels will be newly installed in the coming decades.

This article has been updated.