We've been talking a bit about solar manufacturing processes at GetSolar lately, since most (if not all) of the innovation in solar energy generation occurs at that stage. Most discussion of solar manufacturing 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 and energy, 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 of energy that goes into them? In other words, are they energy net positive? We'll use a simple payback period to take a look at this question.
Energy Used in Manufacturing / Energy Generated per Year in Use = Energy Payback Period.
The energy payback periods for solar panels have come down significantly over time, with most recouping their energy consumption in two to five years. Since solar PV panels typically have a useful life of 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 of solar panels are exactly alike, the authors draw distinctions between the energy payback periods for individual solar technologies, including current multicrystalline, current thin-film, projections for multicrystalline, and projections for thin-film.PV FAQs
With improving technology, thin-film solar panels could reach a one year energy payback period! That's impressive -- especially given the lifecycle costs of other energy sources. Solar has a great energy payback already, and it's only getting better. Keep your eyes peeled for improvements in solar technology and manufacturing to follow how this metric improves over time.