Wind and hot air
Engineers want the facts on wind power and other renewable-energy sources before jumping on the alternative-energy bandwagon. And Machine Design is asking for your help in determining the most worthless engineering course.

Unintended consequences and wind turbines

A few months ago, my wife and I took a cross-country drive from Utah to New York. I was amazed to see the thousands of wind turbines that now dot the land. I couldn’t help but remember the ruckus that was raised a few years ago over the unsightly nature of cell towers. But the rows and rows of perfectly aligned wind generators is a lovely sight. There just seems to be factions of society that complain about some intrusions or restrictions and ignore others. I’m all in favor of energy independence, but are we trading our oil and coal for a less desirable future? How closely spaced would wind turbines have to be across the whole of America to supply even 15% of our energy needs? I’m not sure I want to photo edit out every windmill from a picture of a mountain!  --  E. Richard Cox

My concern is, if we build enough windmills to provide anywhere near enough electric power to meet our needs, Mother Nature will likely have a trick up her sleeve to frustrate us.

I like the idea of solar cells, but here again one must ask how much will we have to invest in solar cells to begin with, and then how much will we have to spend annually to replace defective or worn-out solar cells? And what will be the maintenance costs due to ice, snow, and dust if we try to use solar power to generate anywhere near the number of kilowatt-hours we’re getting from coal?  --  Alex Kovnat

Machine Design is a great magazine and helps people be better engineers. However, sometimes the editorials sound a bit right-wing. Maybe I am wrong, but that is the impression I get. Is it really true that the whole wind turbine industry is a mistake? Are there two engineering sides to that story? And are you also a climate-change skeptic?  --  Dudley Jones

I never said the wind-turbine industry is a mistake. If you are referring to the editorial on wind-turbine power usage, I am merely pointing to an issue that the wind industry has not publicly addressed. In my opinion, the industry shoots itself in the foot by not clearing the air on issues raised by their its critics. And isn’t being a skeptic much better than being gullible? — Leland Teschler

Wind-turbine power consumption is surely a myth, at least that’s the likely line we’ll hear from American Wind Energy Association on the subject (“How Much Power Does It Take to Run a Wind Turbine?” Aug. 12). Whenever anyone tries to pin down the numbers relating to wind energy, a large smoke screen of double talk emerges from the AWEA.

This trade group is betting that lawmakers and the general public are just too busy or too lazy to check out the facts. And with two-thirds or more of wind companies’ equivalent gross revenues coming from sources other than selling electricity to the grids at market rates, its a gamble they need to win.  --  Bob Abernathy

Sadly, the only reason we have these discussions is because political sentiment and power, rather than rational thought and engineering through the free market, has forced the “green” energy issue to the front of the line. The need for wind turbines is totally artificial — do the math. I am an engineer and have done the math. Wind power has been championed in popular thought even though it is a woefully poor means of energy production. -- K. Abmo

American standards first

I am baffled by the recent article on E-Stops (“E-Stop and Go: Safely,” Jun. 22). I am trying to understand why the authors continually focused on European standards when the article is printed in a great American publication. Both the table (pg. 36) and the excerpt (pg. 40-41) “Applicable standards...” reference DIN (Deutsches Institute für Normung – Germany) & EN (European Norme), in addition to ISO (the true international standard). I even checked the ISO web site (www.iso.org), and each standard listed is known only by the ISO prefix, not the other country-specific labels.

Although briefly mentioned in the excerpt, the U. S. National Standards (ANSI & NFPA) get little attention. They should have been the focus, unless your publication has more distribution in Europe than in the U. S. I’m not saying ISO standards are not important, I’m just saying our national standards should be reviewed first and in as much detail as that used on ISO standards. After all, the U. S. standards take precedence over ISO and European standards in the USA. -- Walter Hall

Thanks for your feedback. The recent changes to the international standards related to safety of machinery have had a profound impact on U. S. manufacturers of machinery, equipment, and control systems being shipped to the EU since they took effect Jan. 1 of this year. Conformance to these new requirements can be especially challenging to U. S. manufacturers that may not be familiar with these new directives or the standards they replace. Also, the international classifications for E-stops and stop switches tend to be particularly detailed and explicit, while many U. S. standards place these devices into more-broadly defined classifications. The article attempts to outline all applicable U. S. and international standards, while highlighting some of the most-relevant industry/application-specific requirements such as OSHA 1910, ANSI B11, NFPA 79, FDA CRF Title 21, Part 1020, and SEMI S2-93. — Joseph Torzillo and Lance ScottEAO Switch Corp.

Why the useless information?

I wonder if your readers recall their undergraduate work and how much of it involved material they would never need. As a new faculty member in the electrical-engineering departmental, I once asked one of the older professors, “Why do students have to take advanced calculus? They will never use it.” He replied, “The math department would lose some faculty members if we didn’t send students over.”  -- Stuart A. Hoenig

Do you remember a particularly useless course you had to take to get your engineering degree? Send us your suggestion for the most worthless engineering course at mdeditor@penton,com, and be sure to put “College course” in the subject line.

© 2010 Penton Media, Inc.