We, as an industry, have our work cut out for us in coming years.
Months ago an industrial energy efficiency consortium that puts on training events held a two-day workshop on motors. Motors! Talking about the common Swingline stapler for two days would be more interesting. The efficient motor uses less energy in the amount of the difference in the reciprocals of old minus new. I.e., (1/eff – 1/eff). Multiply by nameplate horsepower then by 0.5 (don’t ask, just do it) then by annual hours of use. Bingo! There are your savings. Two days!
There are more complex issues that may not be addressed. One of these issues is, what is it that makes a motor more efficient? Tighter windings and closer tolerances – I think. I don’t care because the impacts are infinitesimally small compared to what end users ought to be doing. This results in less slip, which means the efficient motor actually runs faster. Here is the dirty secret: An efficient motor may be three percent more efficient but as it runs faster on a constant speed fan or pump it would increase shaft power – power transferred to the impeller / fan wheel by 9%. Increasing the load by 9% but doing it more efficiently by 3% does not save energy. Quite the opposite, actually. If one changed sheaves, which isn’t going to happen, or if the equipment is properly controlled by a variable speed drive, it may actually save energy.
On the whole, it is highly possible that efficient motors result in greater energy consumption.
Recently, we were meeting with regulatory staff and the topics of lighting and motors surfaced. Apparently, the investor owned utilities are clinging to, and concocting ways to hold onto savings for efficient motors and lighting; minimum efficiencies for which thanks to the benevolent federal government are being ratcheted up by fiat. Clinging like Milton and his beloved stapler.
Give me a break. If programs are still relying on savings from motors, there is a major problem in Denmark. How about considering what the motor is turning? The load on the motor could probably be reduced by 50%, while they are going to “save” 3% with a stupid new motor that runs faster and uses more energy.
I can see what is going to happen. Some utilities are going to whine to the regulators that all their savings opportunities are going away because the feds have ratcheted up standards. Regulators should respond with the equivalent of “Gee, that’s really unfortunate. Since you’ve installed all these motors that use more energy over the years, I think we will raise your savings target by one additional percentage point.” Ironically, I learned that negotiating tactic from a utility. “You think the penalty is too harsh? I’ll add 50%. Would you like to counter that again?”
Ironically, on the same day as the meeting with the regulatory staffer, I received information I had asked for purposes of evaluating the potential for retro-commissioning of a mid-size high school just over 250,000 square feet. I had asked for the energy records. The facility is using at least 50% more electricity than it should and 50% more natural gas than it should – easy. It is using as much energy off peak as on peak. The power factor is lousy. With these symptoms, I bet I can call three top, major energy saving opportunities given the types of systems they have. I’ll just leave it at that because it’s intellectual property available for a price.
I’ll bet my house that we can reduce their energy consumption by at least 30% with well under a five year payback. It could be one year or three years, depending on what needs to happen to fix the causes of the waste.
Trust me when I tell you, efficient motors and new lighting will not be part of the 30% solution.
On the nearly useless EE front, see which internet browsers are most efficient. However, the impact on battery life is worth noting. If you don’t use the overpriced internet during air travel, kill the browser.
The president says federal vehicles will all use “clean” fuel by 2015. What does that mean? One percent of the fuel will come from reconstituted plastic grocery bags recovered from a landfill? Meanwhile, the federal vehicles excluding military, guzzled 7% more gasoline than the previous year, using 322 million gallons of gasoline. Congratulations. I’m always pleased to be told how to live by hypocrites to whom no rules apply.
written by Jeffrey L. Ihnen, P.E., LEED AP