Ozzie Zehner’s Book “Green Illusions”

Here’s a lecture by Ozzie Zehner, whose popular book “Green Illusions” is making the rounds. Indeed, there is a great deal of truth here. In particular, we’re seduced by the sexiness of renewable energy, and in some cases make extremely illogical decisions to deploy it.

Zehner provides an example of a gentleman who cut down two deciduous trees that had wonderful passive solar effects (providing shade in the summer, but letting the sun pass through in the winter) because he was so in love with the concepts of having solar panels on his roof. Ozzie showed with great ease that the net effect to the environment was fiercely negative. There is no doubt that we dote over solar, wind, etc., at the expense of energy efficiency and conservation solutions that are, in some cases, hundreds of times more effective in environmental benefits. And if you think this can be asinine at the personal/private level, try to imagine what happens at a governmental scale.

Where he gets into trouble, I believe, is when he implies that, for various reasons, clean energy does not and cannot replace fossil fuels. Wind represented 4% of our grid-mix last year – power that would have come from fossil fuels. Zehner points out that wind energy requires the use of fossil fuels to extract the raw materials, and then fabricate, transport, install, maintain, and decommission the turbines. All true. But the energy return on investment (EROI) for wind energy, i.e., the cumulative electricity generated divided by the cumulative primary energy required to build and maintain a turbine, is quite attractive. EROI for wind ranges from 5 to 35, with an average of around 18. EROI is strongly proportional to turbine size, and larger late-generation turbines are at the high end of this range, at or above 35.

For the record, I object to the book’s subtitle, “The Dirty Secrets of Clean Energy and the Future of Environmentalism.” The fact that clean energy is not steady, inexpensive, easily stored, transportable, and fungible — and the concept that some amount of energy goes into building a wind turbine — are anything but secrets.

Where Zehner and I are in 100% agreement is that we both recognize that we, as a culture, need to change our way of thinking about energy. As much as I believe in clean energy, it’s obvious that replacing the world’s ever-growing use of energy with renewables is an unwinnable war, at least at this point in our civilization’s technological evolution. The real low-hanging fruit here is efficiency and conservation, and these things happen to the degree that the consumer becomes more aware of the way he’s voting with his wallet. Every dollar we spend sends a certain extremely powerful message. Let’s understand that, and communicate our interest in sustainability.

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One comment on “Ozzie Zehner’s Book “Green Illusions”


“(EROI) for wind energy, i.e., the cumulative electricity generated divided by the cumulative primary energy required to build and maintain a turbine, is quite attractive.”

Along with different EROI, different types of electricity generation have quite different grid requirements, whether they are intermittent, dispatchable, baseload etc. Some types require more expensive grid infrastructure such as backup and transmission than others. We shouldn’t forget the energy costs of the grid in order to deliver the power on demand if that feature is assumed.

For example, if I live off-grid and have PV panels with batteries and inverters, I’d need to include in the EROI calculation the energy cost of the PV panels plus the energy cost of the batteries and other hardware.

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