By Jonathan Marshall
What do bars, restaurants, hotels, casinos, laboratories, hospitals, and supermarkets have in common? Ice machines—and big energy bills to power them.
PG&E’s pioneering Food Service Technology Center (FSTC), based in San Ramon, estimates that California is home to about 300,000 ice-making machines, out of a national total of at least 2.5 million. They make your tea and soft drinks more refreshing, keep display foods fresh, and provide a delicious way to cool your mouth on hot days.
But all this takes energy. Ice-making machines in the United States draw an estimated 13,500 gigawatt-hours of electricity each year, or about as 2 million typical homes consume each year in PG&E’s service area. Powering them all requires more peak generating capacity than provided by PG&E’s twin nuclear reactors at Diablo Canyon Power Plant.
Last year, the FSTC conducted a test at several food service facilities to gauge how much electricity could be saved by switching to more efficient ice-making equipment. Second, and even more interesting, the researchers investigated whether and how much peak power demand could be reduced in the afternoon by installing timers to run the machines only at night and in the morning.
A new report on the findings suggests there is big room for energy savings in this market. Projected energy reductions at the demonstration sites averaged around 30 percent. Bill savings were an even more impressive 40 percent. One reason for the extra dollar savings was the reduction of peak demand, which costs more for utilities like PG&E to supply with generation.
At Bridges Restaurant and Bar in Danville, replacement of the existing ice machine with a larger, high-efficiency unit eliminated the establishment’s need to buy extra ice on hot days. It also cut annual energy use by about 30 percent, or 4,300 kilowatt-hours. Thanks to the reduction in peak energy demand, the total cost of powering the machine dropped about $665 a year, or 36 percent.
The executive chef and partner of Bridges also reported great savings on water and much quieter operation with the new machine. Indeed, he was happy enough that he agreed to host a showcase event in October for vendors of energy-efficient ice-making machines and lighting.
The Oakland Museum cafeteria fared even better in the tests. Its existing 10-year-old unit was none too efficient and didn’t have enough capacity to shut down during peak hours. Swapping in a larger, modern unit cut energy use 35 percent, shaved peak demand by almost a kilowatt, and slashed annual energy costs by almost 50 percent.
PG&E project manager Charlene Spoor notes that with the recent transition of small and medium business customers to Time-of-Use pricing, which charges them less during off-peak hours, “this project illustrates one of the best ways that restaurant owners can reduce their usage and save money. For food service operators there are few better options for shifting demand to less expensive times, since for many their busiest periods are during utility peak hours.”
“In the foreseeable future,” the report concludes, “it is conceivable that all ice making in commercial facilities will be during non-peak periods, and in many cases, during the off-peak hours of the night.” That would represent a win for customers by lowering their bills; for utilities by lowering their costs; and for the environment, by reducing the need for polluting generation.
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