Friday, August 18, 2017

How Misleading are Solar Yeilds?-- A Link

Here is an excellent discussion by Gail Tverberg, over at  How Misleading are Solar Yields?.

While yes the main topic is indeed that named in the title, she also goes into an excellent discussion of Energy Return on Energy Investment (EROEI:  It is the ratio of energy spent to the energy produced. ) and its origins as a measure if energy return on human (and animal) labor.

She also deals with some important social issues when this ratio drops too low. Societal collapse seems alarmist, but others like inability of governments to collect sufficient taxes, seem to describe our current situation.  She refers to this book:

The Upside of Down: Catastrophe, Creativity, and the Renewal of Civilization
Jan 31, 2008
by Thomas Homer-Dixon

Her basic point is that the EROEI on PV Panel is (Probably grossly) overestimated.  She's probably right about that to some degree, since mostly we settle for industry figures. The complementary problem for oil, however, is that domestic oil production is also heavily subsidized which means we don't really know the true cost of extraction, and neither do we know the EROEI on it. 

In any case, the EROEI is certain to be less than we have historically been used to.  This has two implications: The first is that we must devote a larger share of the economy to developing and maintaining our energy supply.  And the second is that we will not be able to live as comfortably as we are used to.  If our unequal society is unable to adapt to this new condition, it will not survive, and this would be catastrophic.

While some of the issues in measurement  of EROEI return on PVs she raises I believe can be addressed, it is an important discussion of these issues, and as I indicated above EROEI issues in general.