Does a solar power system produce more energy than it took to make it?
This is an important question. No power source would be a viable long term solution if it never produced more power than it took to make it.
The good news is that modern solar cells reach “net energy gain,” or “energy payback,” in only a few years. Since they produce power for decades, this makes them a very viable source of energy.
The biggest factor affecting how long it takes a rooftop solar power system to reach “payback” is the thickness of the silicon used in the cells. Twenty years ago, the silicon was much thicker, and the payback time was much longer. But modern manufacturing techniques and other advances have reduced the payback time greatly.
New thin film solar cells have an even shorter payback time than traditional cells, sometimes less than one year!
Most recently, Twin Creeks Technologies in California revealed a new technique for creating ultra thin wafers of silicon. If successfully deployed for manufacturing solar cells, this technology could further reduce the cost of solar electricity, and the time to net energy gain.