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You took my interpretation of efficiency in a totally unexpected direction, which is cool and let me learn something new! However I don't buy EROEI as being a

by cjslep 7y ago

You took my interpretation of efficiency in a totally unexpected direction, which is cool and let me learn something new! However I don't buy EROEI as being a good measure in a discussion about long term climate change and the wholistic picture of an energy source. EROEI is too short-term focused (on energy break even) instead of looking at the lifetime of an energy source. Oil plants and internal combustion cars need to account for the years of shipping logistical distribution and mining/drilling when looking at the lifetime of an oil plant or the lifetime of the car. Compared to the marginal energy cost of maintenance of a PV cell or wind turbine over the lifetime of those power generating structures. The EROEI at the end of the energy production lifetime may favor energy-intensive short term sunk costs with low long term marginal costs (wind and sun) instead of favoring low-entry-incumbents with high energy operating costs (oil and it's existing logistical infrastructure). So I disagree it's "not controversial" and I also think looking at EROEI for the break even point is kind of like looking at bullet holes on planes without Abraham Wald around.

coldtea 7y ago
>However I don't buy EROEI as being a good measure in a discussion about long term climate change and the wholistic picture of an energy source. You're right, it's not (climate wise), as it hides the externalities. But it's my understanding that the parent meant "efficient" in the way EROEI is.
tetraca 7y ago
The more we have to invest into standing up an energy source, the more cogs you have to put into simply maintaining the energy infrastructure, and the less that we have available at any given time to upkeep the rest of our logistical chains. Consider arguably the worst scenario: a civilization that has to derive all its energy needs from ethanol (which IIRC, has a 2:1 ratio). At least half of it is going to have to be dedicated to farming grain for energy and processing it into ethanol for the rest of that civilization to function. And of that non-farming half, how much of that will end up being support industry for the ethanol creating half? The amount of high technology industry that could ultimately be supported by that civilization would be dramatically lower because a much higher proportion needs to be dedicated to lower necessities.
- cjslep 7y ago
  Yes, this is exactly why I don't like EROEI: it hides this fact, and is explicitly a measure favorable to high operational / low capital energy cost sources.

by cjslep 7y ago

coldtea 7y ago

>However I don't buy EROEI as being a good measure in a discussion about long term climate change and the wholistic picture of an energy source. You're right, it's not (climate wise), as it hides the externalities. But it's my understanding that the parent meant "efficient" in the way EROEI is.

tetraca 7y ago

The more we have to invest into standing up an energy source, the more cogs you have to put into simply maintaining the energy infrastructure, and the less that we have available at any given time to upkeep the rest of our logistical chains. Consider arguably the worst scenario: a civilization that has to derive all its energy needs from ethanol (which IIRC, has a 2:1 ratio). At least half of it is going to have to be dedicated to farming grain for energy and processing it into ethanol for the rest of that civilization to function. And of that non-farming half, how much of that will end up being support industry for the ethanol creating half? The amount of high technology industry that could ultimately be supported by that civilization would be dramatically lower because a much higher proportion needs to be dedicated to lower necessities.

cjslep 7y ago
Yes, this is exactly why I don't like EROEI: it hides this fact, and is explicitly a measure favorable to high operational / low capital energy cost sources.