We’ve been talking a bit about solar manufacturing processes at GetSolar lately, since most (if not all) of the innovation in solarenergy generation occurs at that stage. Most discussion of solarmanufacturing revolves around how to best reduce cost. But the amount of energy used to manufacture solar photovoltaic (PV) panels — also called solar “modules” — often merits attention as well. It takes effort andenergy, after all, to fabricate the various parts of a solar module,like the solar cells, backsheets, frame and wires.
So, do solar panels generate more electricity than the amount ofenergy that goes into them? In other words, are they energy netpositive? We’ll use a simple payback period to take a look at thisquestion.
Energy Used in Manufacturing / Energy Generated per Year in Use = Energy Payback Period.
The energy payback periods for solar panels have come downsignificantly over time, with most recouping their energy consumption in two to five years. Since solar PV panels typically have a useful lifeof 25 to 30 years — and sometimes even longer — solar offers a very good long term energy generation option.
The National Renewable Energy Laboratory publishes some detailed information on this topic; in addition, you may find this overview from the U.S. Department of Energy helpful. Because no two types ofsolar panels are exactly alike, the authors draw distinctions betweenthe energy payback periods for individual solar technologies, includingcurrent multicrystalline, current thin-film, projections formulticrystalline, and projections for thin-film.
With improving technology, thin-film solar panels could reach a oneyear energy payback period! That’s impressive — especially given thelifecycle costs of other energy sources. Solar has a great energypayback already, and it’s only getting better. Keep your eyes peeled for improvements in solar technology and manufacturing to follow how thismetric improves over time.
Image: Source: NREL, PV FAQs