I recently wrote about the thermodynamic black hole; articles about ERoEI keep popping up in my in tray that truly baffle me…… As Alice Friedemann told Chris Martenson in the podcast I discussed in the aforementioned blog post, “everyone disagrees on what to leave in or out of their ERoEI analyses”….
I was pointed to another blog called Ramez Naam where the following was published…:
There’s a graph making rounds lately showing the comparative EROIs of different electricity production methods. (EROI is Energy Return On Investment – how much energy we get back if we spend 1 unit of energy. For solar this means – how much more energy does a solar panel generate in its lifetime than is used to create it?)
This EROI graph that is making the rounds is being used to claim that solar and wind can’t support an industrialized society like ours.
But its numbers are wildly different from the estimates produced by other peer-reviewed literature, and suffers from some rather extreme assumptions, as I’ll show.
Here’s the graph.
This graph is taken from Weißbach et al, Energy intensities, EROIs, and energy payback times of electricity generating power plants (pdf link). That paper finds an EROI of 4 for solar and 16 for wind, without storage, or 1.6 and 3.9, respectively, with storage. That is to say, it finds that for every unit of energy used to build solar panels, society ultimately gets back 4 units of energy. Solar panels, according to Weißbach, generate four times as much energy over their lifetimes as it takes to manufacture them.
Personally, I think these figures are a bit on the optimistic side, yet the author has a problem with them for being too low…
…click on the above link to read the rest of the article…