Energy conservation importance understated
I was reading Ken Goldstein's “Unfiltered” column “Energy conservation: Where should it fall on your list of priorities?” in the on-line version of CleanRooms and I take some exceptions to Goldstein's position.
I think Goldstein has understated today's business environment and the importance many semiconductor companies are placing on energy conservation. If you read the public policies being presented by many semiconductor companies you'll see that they are committed to energy conservation.
I have recently met with Intel, TI and ST Micro to discuss their energy conservation policies and we are collaborating on ways to reduce energy on the tool and facility side. Your comment that tool energy conservation should be left to the tool manufacturers is not how we owners are going to achieve the SIA roadmap goals for energy conservation.
I agree that much of the potential savings must be a collaborative effort with the tool suppliers but the tool owners can also do their part-this was especially demonstrated with water conservation programs. As for facility systems, many semiconductor companies are targeting the low hanging fruit, but they are also investing resources into comprehensive energy conservation programs and research into methods for reducing energy.
Motorola has saved millions of dollars as a direct result of their energy conservation programs. I recently published an article describing our success. We are also institutionalizing our energy efficient designs in all of our new facilities. The opportunities are tremendous.
In Ken Goldstein's “Unfiltered” column, [March 2002, page 62], Goldstein “disses” energy conservation. Energy conservation should be a goal in every facet of semiconductor or any other industrial facility effort. Finding and saving packets of energy may take time and the energy saved may be small, but finding and saving them is of value. The California power crunch brought on by, among other factors, the push by big industry for deregulation, would have been much more severe had not massive conservation efforts-not necessarily in the semiconductor arena-reduced consumption by close to 20 percent. This reduced the number and severity of the rolling blackouts and brownouts that are not conducive to meeting quality and production goals.
Energy conservative design is one aspect of energy independence. How can you argue with good engineering that reduces energy consumption and saves money? I wouldn't sneer at the 10, 20 or 30 percent potential savings on energy bills good energy design can create.
Goldstein identified eight areas he thought had a relatively insignificant potential for energy saving. Certainly in designing “gee-whiz, state-of-the-art, we're lucky we can do that task at all, the hell with the energy cost” equipment, I agree we should not get too excited about energy conservation until the third or fourth generation of the equipment.
Here are areas where good design can be applied without breaking the bank and, more importantly, can save energy resources.
AIR: Decreasing air velocity from 90 to 70 fpm in an existing facility can lower power consumption by the cube of the fan speed reduction or more than 50 percent. In a new facility, cost savings associated with reduced ductwork lower cooling loads and smaller fans combined with ongoing energy savings are worth considering. Eliminating ductwork by using filter fans reduces fan horsepower and selecting ECM motors in lieu of PSC motors for those filter fan units offer additional opportunity for energy reduction. Not every fab operates 24/7/365 and duty cycling can offer another strategy for energy reduction. Good engineering can identify opportunities that don't threaten the product.
WATER: Chilled, process and DI water may all realize benefits associated with variable speed pumping.
EXHAUST: Goldstein points out that there are savings to be had. At 5-7 tons of air conditioning per 1,000 cfm of exhaust, it makes sense to apply VAV fans with appropriate controls to minimize cleanroom exhaust thereby reducing chiller and exhaust fan energy usage. Perhaps it's time to revisit heat recovery. It's not unreasonable to expect to reduce the 5-7 tons mentioned to a more energy conservative range of 2-4 tons through energy recovery.
LIGHTS: It's hard to get excited about lights but well-designed facilities already use lower wattage fluorescent fixtures with premium cost electronic ballasts. Why do we do that and not examine overall lighting levels? We can evaluate the use of task lighting as well as the use of other low energy lighting fixtures. Surely we can realize benefits without “walking around in the dark.”
Percentages are a handy way to address a statistical issue. In Goldstein's perspective, a small percentage saving of a small percentage cost seems to be small potatoes. Use a different analogy: Think of a river and that each packet of energy saved is a trickle that joins with other trickles to form that river representing the plant's energy reduction. Each river joins with other rivers forming a torrent not of water, but of oil. Whether that saving results in a reduced dependence on foreign oil, fewer rolling blackouts, lower product prices or dollars in the bank, it is an opportunity we must take seriously.
Ken, I hear what you're saying, but I think we can save energy and continue to produce superior, cost-effective products, safely. We can and should do it all. Good engineering doesn't cost. It pays.
-Raymond K. Schneider P.E.