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11 December 2016

This could be it for Silver

Commodities headlines have been dominated again this year by petroleum. Sluggish prices, falling extraction rates and exporting nations in trouble have provided much fodder for the specialised media. As a matter of fact, prospects have not changed that much from last year, in spite of a deeper than expected fall in extraction rates.

There are other natural resources though, that provide perhaps a more vivid view of your relationship with the finite planet we leave in. Recent data dug out by Steve StAngelo at the SRSRocco Report points to a peak in world Silver extraction in 2015. The likelihood of this being a terminal peak is rather high, more so than 2015 setting the terminal peak for petroleum.

05 December 2016

EROEI estimates show PV to be a fully mature technology

"The EROEI of Photo-Voltaics can be whatever you like these days" a friend of mine said once after attending a bio-physical economics conference. It epitomises a growing problem in this field, while the broad concept of net energy or Energy Return on Energy Invested (EROEI) is broadly accepted there is no unified methodology for its calculation. Different researchers apply different methods producing markedly different results.

Photo-Voltaics (PV) is energy source where this problem has been more acute. Equipment and installation prices collapsed four or five fold since 2010, but published EROEI studies have not converged; in fact it appears they dispersed even further.

Fortunately, another friend, Rembrandt Koppelaar, has recently finished a study assessing these assorted EROEI estimates, entitled Solar-PV energy payback and net energy: Meta-assessment of study quality, reproducibility, and results harmonization. As it turns out, low EROEI figures are largely an artefact of outdated data and double accounting. A message by Rembrandt summarising the results of his study is reproduced below.