But what of 24/7 supermarkets, filled with frozen foods in need of refrigeration, as well as conditioned air for customers?
The answer may be self-generating, on-site power production plants.
Three such technologies were discussed at the 21st-annual Food Marketing Institute Energy & Technical Services Conference held here.
Timing was everything. Fear of brownouts in California at the time of the mid-September conference was causing supermarkets to reduce lighting and take other energy-saving measures. During a tour of two area stores, FMI attendees saw that half of the overhead lights were turned off, and that there was no lighting on most of the display cases.
Lose the Grid“Try to avoid the use of grid systems, some of which are over 50 years old,” advised Russell Spitz, Ph.D., vice president, Vision Power Systems, Jacksonville, FL. “A power plant doesn’t go down. A transmission line goes down. So the alternative is to use direct power.”
Spitz’s concept calls for on-site generation with piston-driven reciprocating engines. A key is to significantly reduce power bills, thus the concept works best in areas of high utility costs such as the Northeast, Midwest, and California.
He also maintained that direct power minimizes supply variances that can be as high as 10% to 20% from conventional sources.
DeregulationIronically, he said, direct power becomes even more important as the deregulation of public utilities takes place. “Deregulation puts more strain on an already overloaded transmission and distribution system, causing more blackouts.”
He added that site-generation power plants operate at 75% load while rated at 100% load all the time. They have dual-fuel capabilities, usually 95% gas and 5% diesel fuel, that can automatically switch to 100% diesel.
Spitz’s concept means a store using an on-site plant would be disconnected from a traditional grid and the grid would not be used as a backup. “That kind of backup is a waste of money and not necessary.”
Another alternative was offered by Richard Sweetser, president, Exergy Partners, Herndon, VA. He suggested the use of microturbines, which he defined as units of less than 500 kW. He said there about 1,000 such units now operating.
“Currently there are three U.S. manufacturers with a fourth joining next year,” he said. “Canadian, European, and Asian products are also on the market or emerging.”
What They’re Like, How They WorkCurrent models stand about 5 ft high and consist of air inlets, a digital power controller, high voltage terminal block, a connection bay, and the microturbine.
Sweetser noted that current models are still too small for conventional supermarkets, although some units are being used in fast food restaurants. He said he expects larger units to come out in the next three to four years.
For Paul Eichenberger, vice president, Business Development, FuelCell Energy, Rocklin, CA, the secret may be fuel cells.
Part of the blame for supply problems, he said, can be leveled on higher power demands from computers and communication technology. “There is an increase in the need for power. We have to be producing power on-site.”
He suggested high-efficiency fuel cell power plants for stationary power generation. Basically, in one approach, natural gas enters the fuel cell stacks and, with the assistance of preheat, generates power and heat. Fuel cell components include stainless steel, nickel, ceramic powders, and carbonates.
Eichenberger said work continues on producing units that have readily available materials. He added that “We need to reduce our manufacturing costs by elimination of first-time costs, purchasing supplies in large volume, continuous process improvement, and improved product performance.”
He said field trials are currently underway in Alabama, California, Washington State, and Japan.
Publication date: 10/16/2000