Small Wind?

You are no doubt aware of NESEA’s Building Energy 2009 conference coming up in Boston March 10, 11, and 12. This writing springs from thoughts surrounding a conference session I am chairing on Wednesday March 11 at 11:00 a.m. titled “The Reality of Small Wind Turbines”. While I hope the session will address that topic directly and fully, here is an opportunity to provide some background information on wind energy and energy resources, putting them in the larger context of overall energy use in the United States.

We learn to use language early on to connect with other people and try to make sense of the world. “Big” and “small” are two of our most useful but potentially misleading adjectives. Anybody who has erected a “small” wind turbine knows this; a nominal 6.6 kW machine sports two blades that are nine feet long, thus sweeping out an 18-foot diameter circle. This “small” turbine weighs 450 pounds and may sit atop a tower more than 100 feet above the ground. So this is pretty big; installation is hardly a weekend do it yourself project.

On the other hand I recently walked alongside some blades that were in transit for a giant 3.6 MW (3,600 kW) three-bladed wind turbine. They each seemed to be in excess of 150 feet in length. In electric power terms, once in operation this behemoth is capable of well over 540 times the output of the “small” wind turbine example. Now that’s big. Or is it?

Let’s keep the overall energy picture in perspective. If you believe in the importance of whole-systems thinking, you are mindful that wind and the other renewable energy resources are only a small part of the totality. Here is a chart that shows that.

It is shamelessly borrowed from the Lawrence Livermore National Laboratory showing how most of our energy flows through our lives in the United States.  Although not stated on the chart these data appear to be 2005 or 2006 vintage. The units of energy are enumerated in Quads, or quadrillions of BTUs. On the left side are our primary sources of energy; on the right are the principal categories of usage. Note in the middle we have the conversion of primary energy into electricity which is then transmitted and distributed to end users. Wind energy is less than 0.2 percent of our total energy use.

There is a lot of useful information on this chart. As a nation we annually use about 100 Quads of energy. Looking at the petroleum segment in the lower left, about 60 percent of our petroleum is imported (In 1970, pre-OPEC, imports were about 20 percent I believe). On the extreme right hand side we see that the overall amount of energy that is “lost” (i.e. thrown away or otherwise not put to useful work) is about 56 percent of the total.  Just looking at electricity generation, 67 percent of the input energy is lost one way or another before the electric energy finds its way to end users. This is big.

A thoughtful person understands why energy is so thoroughly embedded in our economic, environmental, political, and social lives. Striving for a so-called “sustainable energy future” is not a simple matter. But Mahatma Gandhi has famously said, “Whatever you do will be insignificant, but it is very important that you do it.” That is really big.