As costs continue to fall, solar panels harvesting solar energy stand as an attractive replacement for fossil fuel-fired power plants.
But before jumping aboard the solar train to stop climate change, however, it is a good idea to assess if making more panels will solve the problem or add to it.
Solar power plants do not create air pollution like coal or natural gas ones, however, whether or not the pollution and energy needed to make a solar panel in the first place outweighs its benefits is more debated. Purifying the silicon used in the panels is a particularly energy intensive process.
According to a report in Nature Communications, Wilfried van Sark and his colleagues have calculated the energy and emissions required to make all of the solar panels installed in the past 40 years. Their study is the first to account for increased efficiency in manufacturing over time using data from the International Energy Agency. Pollution from the manufacturing process, as well as the avoided pollution from installing a panel, will also depend on where and when it was made or installed.
Accounting for those factors, the study showed that solar panels made today are responsible, on average, for around 20 grams of carbon dioxide per kilowatt-hour of energy they produce over their lifetime, versus 400-500 grams in 1975.
Similarly, the time needed for energy produced by a solar panel to exceed the amount used to make it has fallen from about 20 years to about 2.
The team found that for every doubling of the world’s solar capacity, the energy required to make a panel fell by around 12% and associated carbon-dioxide emissions by 17-24%. Bloomberg New Energy Finance estimates that the solar industry has doubled in size at least seven times since 2000.
In the model, the global break-even for solar panels could have come as early as 1997, or could come as late as 2018. Beyond that point, each installed panel really would be mean net savings on energy and emissions.
So, with this study at least, we can say that more solar panels will mean fewer overall emissions and a net gain in energy.