In preparing my previous post on Net Energy Trends I wanted to include a back of the envelope calculation on the ERoEI of hydro electric power using the Three Gorges Dam as an example. But I got my decimals pretty muddled leading to an answer that was implausible. But I’ve now had a few days off to clear my head and I put a new battery in my calculator and so hopefully the calculation is now on the money.
Looking at just the labour and embedded energy of the concrete and steel and assuming a 45% capacity factor and 70 year life yields a partial ERoEI of 147. And so, despite substantial environmental harm and social disruption I must give dispatchable hydro electric power a big thumbs up. See the calculation below the fold.
The Three Gorges Dam on the Yangtze River in China is the largest hydroelectric scheme in The World. Operational since 2008 it has 22.5 GW installed capacity. The Itaipu Dam on the Parana River between Paraguay and Brazil produces a similar amount of electricity from 14 GW capacity and achieves this through a higher capacity factor.
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