  The wide public sees solar energy as the future of mankind, and media
channels quite oftenly states that our challenge is to improve efficiencies and
reduce cost. However, one may point some unconvenient truth's about the
physical limits we are facing, that are barely discussed by the public or even
by scientists and institutions that are strongly biased towards a picture of a
sustainable oil free energy in the future. In this work we discuss some of
those physical limits of photovoltaics based on the principle of the Hubbert's
theory for the oil peak, evidencing that much of the research is focused on
photovoltaic efficiencies and this parameter is widely overestimated: better
efficiencies oftenly are the result of complex technologies that are expensive
and not scalable. In this context, if fossil fuels proved not replaceable, it
is very likely that our socioeconomic ideas based in the past will not
withstand an energy transition to high cost and low quality sources.
