Palm Beach County Utilities Director Bevin Beaudet reported on his department’s energy-saving initiatives at Tuesday’s meeting of the Palm Beach County Commission.
Beaudet noted that his department is the third-largest water and wastewater utility in Florida. “We serve 520,000 residents with 558 employees,” he said, adding that the department’s operating budget is $115 million a year, with about a $50 million capital budget.
The county utility is recognized nationally as an industry leader.
“We’re a big water utility,” Beaudet said. “We operate four water treatment plants with a capacity of 103 million gallons a day, two wastewater treatment plants with a capacity of 59 mgd. We reclaim 22 million gallons a day of our water. We also put 4 million gallons a day into our wetlands, Green Cay and Wakodahatchee. If you were to stack all of our pipes end-to-end, it would go from Miami to Seattle. Half of the value of our water utility infrastructure is pipelines under the ground.”
But the department is also the largest energy user in the county. “We have 800 meters that are read every month,” he said. “We use 90 million-plus kilowatt hours per year. That’s almost $10 million a year, and that’s 8.5 percent of our operating budget. That’s our largest expense except for labor, so it’s a pretty good candidate for cutting if we want to save money for our customers.”
In 2010, the department set a goal in its strategic plan to reduce energy use by 10 percent on a kilowatt hour per dwelling unit basis.
“Since we are growing and since the rates keep going up, we can’t use money as an indicator, so we’re using a unit indicator of kilowatt hours per dwelling unit, so it’s an efficiency rating,” he explained. “We also wanted to provide half of that savings, 5 percent, by using alternative or renewable energy sources.”
The department has done a number of studies to investigate energy reduction, including one in 2006 when they looked at all of their plants, and recently for a proposed biogas generation project.
The plants, including the wells, are using 85 percent of the energy consumed by the utility. “We really didn’t know that, so we’ve focused our energy-saving initiatives on our plants,” Beaudet said.
The survey discovered that the ozone generators used to disinfect water in two of the lime softening plants were major energy users. “They’re big energy hogs,” Beaudet said.
Membrane plants for reverse osmosis are also big energy users. “The more we focus on energy initiatives at our membrane facilities, the more successful we can be,” he said.
Pumps are also big energy users. “We have thousands of pumps in our system,” he said. “Some of them are as much as 1,000 horsepower, and we have hundreds of pumps that are 400 to 500 horsepower, so we do a lot of pumping,” he said. “We move a lot of water around, and that costs a lot of money. The biggest energy users in our plants are our distribution pumps. Those are the pumps we use to send the water out of the plants and pressurize our system.”
The wells also use large submersible pumps, and the wastewater treatment plants use a lot of energy in their aeration systems. “We were able to identify these areas as candidates for cutting,” he said.
The department is engaged in three different initiatives to cut down on energy use.
“We did facility upgrades, we did process changes and we did capital projects,” Beaudet said. “We installed motion-activated lighting, and we replaced all of our lighting fixtures at the plants with energy-efficient ones. This was thousands of fixtures and motion-activated devices.”
They also painted the ceilings of the plants to be brighter and more reflective. “This allowed us to put lower-wattage bulbs in the ceilings and still get the light that we need to do our work inside the building,” he said. “We also replaced some inefficient air-conditioning systems.”
The department also installed variable-frequency drives at the production wells, distribution pumps and other systems.
“That can save a lot of money, and we’ve been replacing those over time,” Beaudet said, explaining that variable-frequency drives operate at the speed needed to perform the task at hand. “Back in the old days, you had big pumps and little pumps. When you had a little demand, you turned on a little pump. When the demand got bigger, you turned on a bigger pump. Pumps were either no power or full power, even if you didn’t need all the power of that big pump.”
A variable-frequency drive coordinates the pump speed with demand. “You get energy savings because you’re only pumping that big pump at the rate that it needs to be pumped,” he explained.
The utility also optimized production well pumps. “We found that we had oversized them, and we were able to reduce the amount of energy they use by making some modifications,” he said. “We also time our plant operations so that we’re doing the hardest work at times when the electricity costs less.”
Some of the energy-efficient upgrades cost big bucks at first, with savings over time. For example, they replaced the membranes at the first reverse-osmosis plant with more energy-efficient membranes at a cost of $5 million.
“We’ve automated our chemical feeds, which also helped save energy, and we replaced the air diffusers with much more efficient ones in the aeration systems in the wastewater treatment plants,” Beaudet added.
Capital projects include replacing ozone water disinfection with an ion exchange system, which is not only more efficient at removing organic material but more energy-efficient than ozone, Beaudet said.
The department is also in the process of sub-metering the various energy-using devices in the plants. “You can’t improve what you can’t measure,” he said. “We started putting meters at various locations in the plants so that we could start measuring how different parts of the plant were doing. We’ve replaced a lot of pumps with more energy-efficient pumps.”
The department has also embarked on alternative energy projects, including a biogas generator that uses methane created by the anaerobic digester at the Southern Wastewater Treatment Plant. “It produces a lot of methane gas,” Beaudet said, explaining that they used to just burn off the methane. “I used to hate seeing that. I’d drive by on the turnpike and see that flare. It used to make me sick because I knew we were wasting energy.”
The department was able to get a matching grant from the federal government to pay for half the cost of the biogas generator, which is an internal combustion engine that burns the methane and turns turbines that produce electricity. “We’re producing 20 percent of the power at that plant by this biogas generator,” he said. “Our biggest energy user is that plant.”
Another project financed through a matching grant approved by the county commission at its last meeting is a field of solar panels on about a half-acre at the Southern Wastewater Treatment Plant.
“That’s going to produce another 125 kilowatts of energy when the sun shines, which is about another 2 percent of our plant use,” Beaudet said. “That makes our plant an extremely green plant, one of the greenest wastewater treatment plants in the country.”