A new study finds that wind turbines have an energy payback of 6 months, which is comparable to the best solar photovoltaic systems. In other words, in their first six months of operation, large wind turbines produce the same total amount of energy that was needed to produce and install them.
That is the conclusion of a comprehensive life-cycle assessment of 2-megawatt wind turbines by Oregon State researchers in the International Journal of Sustainable Manufacturing (subs. req’d).
The myth that wind and solar power are bad investments from an energy-payback perspective has been around for years. It even turned up in the error-riddled 2009 book “Superfreakonomics,” repeated by Nathan Myhrvold, former CTO of Microsoft.
It’s difficult to compare this to the energy payback time for fossil fuel plants, because not only do they require a great deal of energy to construct and fuel, they also cause climate change and mooch off of millions of years and heat and pressure provided by the earth.
Of course, decades ago, when manufacturers had not yet applied mass-production techniques to those then-nascent technologies, the energy payback time (EPBT) of renewables was considerably worse. That’s clear from this chart in “PE Magazine,” the lead publication of the National Society of Professional Engineers.
The European Photovoltaic Industry Association says, “Depending on the type of PV system and the location of the installation, the EPBT at present is between 0.5 and 1.4 years.”
In general, the more sunlight at a solar installation the faster the energy payback. In the future, we can expect a continued improvement in energy payback. Year after year, renewable energy becomes a better and better investment.
By Joe Romm