Improvements in PV technologies over the last decade have brought about notable increases in their EROI. When calculated in terms of the electricity output per unit of primary energy invested (Eq. (2)), The EROIel of PV ranges from 6 to 12, which makes it directly comparable to that of conventional thermal electricity without CCS (4–24).
When instead calculated according to the often employed formula EROIPE-eq=T/EPBT (Eq. (4)), i.e. expressing the energy ‘returned’ by PV in terms of its ‘Primary Energy equivalent’, the EROI of PV is up to 19–38, which puts it squarely in the same range of EROI as conventional fossil fuels (oil in the range 10–30; coal in the range 40–80).
These new results prove that PV is already a viable energy option that may effectively contribute to supporting our societal metabolism, while significantly reducing the depletion of the remaining stocks of non-renewable (fossil) primary energy, and mitigating the concurrent environmental impacts in terms of global warming and polluting emissions.
However, even these remarkable results should not allow one to forget that PV, like all other renewable technologies, must still be supported by an initial investment of primary energy, which is, as of today, of fossil origin. We therefore argue that available monetary and energy resources should be funnelled in the right direction without delay, lest not enough high-EROI fossil fuels are left to support demand during times of gradual shift to renewable resources.
[sciencedirect.com] – The energy return on energy investment (EROI) of photovoltaics: Methodology and comparisons with fossil fuel life cycles. June, 2012.