While driving home after a great Labor Day weekend with friends and family, we ran into scattered showers. My wife helped me figure out the switches that control the timing of the intermittent windshield wipers for both the front and rear windows. (She is the primary driver for our recently purchased family vehicle; I had done a very non-nuclear thing by never getting around to reading the owner’s manual.)
After a brief tutorial, I recognized that the controls were conveniently located beauties of ingenuity that allowed me to pick exactly the right interval at which to make the blades clear the windshield and the rear window. Even as the rain intensity varied and the spray from other vehicles changed, I could find the perfect speed. I was able to adjust the interval to prevent both the annoying squeak of rubber on a dry surface and the vision interference of a window covered with too many drops.
The experience made me realize that Americans most likely associate the word “intermittent” with their easily controlled windshield wipers that can be adjusted to match the demand of clearing their windshield through a variety of conditions. However, “intermittent” is also the word that is frequently used by people like me who are trying to explain to others why we are NOT enamored with the prospects of increasing the use of weather dependent energy collection systems like wind turbines and solar panels.
I now believe we have been using the wrong word and conveying the wrong meaning. Unlike our intermittent windshield wiper systems, with their responsive control systems that allow drivers to pick exactly the right speed to respond to changing demands, the desired output of wind and solar power systems are completely dependent upon the input weather conditions. If there is bright sunshine or steady wind, the output of renewable power systems can be varied a little, but there is absolutely nothing that the operator can do – other than wait for the weather to change – if the wind dies or the sun goes behind a cloud.
Some renewable system advocates wave their hands over that problem and offer the possibility that someday someone else will figure out how to build a better energy storage device than our very limited chemical batteries. That possibility seems quite remote to me, especially considering how much effort several generations of scientists and engineers have put into building better batteries.
More accurate and informative terms that better describe the limitations of weather dependent energy systems include “unreliable”, “unpredictable”, and “uncontrollable”. All of those terms help people to clearly understand that the inherent characteristics of wind and solar energy systems are exactly NOT the characteristics that we want from our electricity supply system.
We want our power to be smooth, reliable, and utterly under control. We want it to be there when we need it. We want it to be delivered at exactly the right rate, with no equipment damaging surges and no failures while we are cooking dinner, washing clothes, or watching an exciting football game.
From now on, I am personally going to avoid using the term “intermittent” and focus on using one of those more descriptive terms when talking about my dislike of efforts to sell wind and solar energy systems to unsuspecting customers. The renewable energy pushers have spend decades obscuring the level of risk those power sources are imposing on an electric power grid that we have all learned to take as almost a birthright of living in the United States or other industrialized, “first-world” countries.
(In support of that statement, here is a link to a 1993 study produced by contractors employed by the National Renewable Energy Laboratory. The purpose of the study appears to be to sell a “don’t worry, be happy” attitude about increasing the penetration of power systems that are only as controllable as the weather.)
Note: The title of this post was changed on September 8, 2011 at the recommendation of a frequent contributor to the Atomic Insights discussion threads.