Producing electricity with photovoltaics (PV) emits no pollution, produces no greenhouse gases, and uses no finite fossil-fuel resources. The environmental benefits of PV are great. But just as we say that it takes money to make money, it also takes energy to save energy. The term “energy payback” captures this idea. How long does a PV system have to operate to recover the energy and associated generation of pollution and CO2 that went into making the system, in the first place?



Energy payback estimates for both rooftop and ground-mounted PV systems are roughly the same, depending on the technology and type of framing used. Paybacks for multicrystalline modules are 4 years for systems using recent technology and 2 years for anticipated technology.
For thin-film modules, paybacks are 3 years using recent technology, and just 1 year for anticipated thin-film technology (see Figure 1). With assumed life expectancies of 30 years, and taking into account the fossil-fuel-based energy used in manufacture, 87% to 97% of the energy that PV systems generate won’t be plagued by pollution, greenhouse gases, and depletion of resources.

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