An energy efficiency project at Agrium in Kennewick is saving enough energy to power about 240 homes served by Benton PUD.
It’s also a win for the fertilizer plant, earning it a $375,000 rebate check presented Thursday.
Agrium took advantage of one of the public utility district’s many energy efficiency programs offered for different classes of customers, said Chris Johnson, the PUD’s manager of power resources.
The PUD is required to conserve energy under the Energy Independence Act implemented after Washington state voters approved Initiative 937 in 2006. But the district has had conservation programs since 1980.
Conserving energy helps keep power rates down for all customers by delaying the purchase of more expensive power to add to the PUD’s portfolio.
Agrium, which employs 65 people to make liquid nitrogen-based fertilizer, operates around the clock 365 days a year.
Key to the plant has been the continuous operation of one of its 800-horsepower centrifugal air compressors at full capacity while others stood by for backup. That’s about the horsepower of a NASCAR engine that would have to run every minute of every day, said John Whitchurch of Cascade Energy in Walla Walla.
About 18 months ago, Agrium started looking at energy conservation measures to fit in with its environmentally conscious culture, said Jon Berg, the manager of the Kennewick Agrium plant.
Managers knew the company needed to replace its 1970s-era compressors and that smaller compressors could do the job.
Working with consulting firm Cascade Energy and Benton PUD, it came up with a plan that allowed it to swap out its 800-horsepower centrifugal air compressors with a 150-horsepower compressor and a 150-horsepower variable drive compressor, along with making other upgrades to the air system.
The project is projected to save about 4 million kilowatt-hours of energy annually, Johnson said.
“This was a very technical project with a lot of moving parts,” Whitchurch said.
The compressed air system had served Agrium reliably for more than 40 years and was central to the plant’s operation, requiring the old system to remain online until the new system was installed and operating.
One of the biggest energy-saving changes was installing a 10- to 15-horsepower blower — about the horsepower of a small riding lawnmower — to move granular limestone from where it was unloaded underground to the top of a five-story building, Whitchurch said.
In the past, 100 to 200 horsepower had been required to blast the sand-like limestone in batches to the top of the building, he said. The new blower system continuously moves smaller amounts.
The new blower system was expensive, but it will pay for itself in energy savings, Whitchurch said.
A new system to take the moisture out of compressed air also has significantly reduced the need for horsepower, he said.
The new air compressor system has smart controls plus a tank the size of a railroad car for compressed air storage, allowing less compressed air to be produced.
The project was partially paid for by the Bonneville Power Administration’s Energy Smart Industrial Program, which works with the Northwest’s industrial facilities through their utilities, such as Benton PUD.