Turbines touted for treatment plants
Wind turbines are increasingly seen as a cost-effective way to produce electricity for wastewater treatment plants, and Rhode Island plants – including the Jamestown facility – are evaluating turbines and a host of other measures to increase their energy efficiency.
Wind turbines were the focus of a Sept. 23 tour of Falmouth, Mass. and Massachusetts Military Reservation treatment facilities drawing power from windmills. The tour was hosted by the Narragansett Bay Commission, which represents all 19 wastewater treatment plants in Rhode Island.
Islanders on hand for the tour were Town Council member Bill Murphy, wastewater treatment plant Superintendent Doug Ouellette and the second-in-command treatment plant operator, Paul Robertson.
Earlier this year, the Environmental Protection Agency selected the Jamestown facility for a regional Wastewater Treatment Plant Excellence Award, which honors the employees of publicly owned treatment works for “outstanding plant operations.”
Robertson said that plant personnel are continuously searching for ways to increase the effi ciency of the plant. In fact, he added, the plant was evaluating a wind turbine proposal long before the council endorsed a municipal windmill for Taylor Point, which happens to be the location of the wastewater treatment plant.
“We are always looking for ways to be more efficient – to be more ‘green’ – and we started evaluating a windmill for ourselves a while back,” Robertson said. “The beauty of the proposal we had [from Alteris Renewables] was that there wouldn’t be any cost to the town. They would build the windmill and they would own it, but they would guarantee a 10% savings in our electricity costs.”
The Alteris proposal was not advanced to the Jamestown Water and Sewer Commissioners because the town decided to launch a feasibility study of one or more municipally funded turbines to power all municipally owned facilities and buildings.
But that doesn’t mean there will never be a turbine at the wastewater treatment plant.
If the town decides to build a municipal turbine at a location other than Taylor Point, which recently failed to pass Federal Aviation Administration muster, the treatment plant could conceivably propose a relatively small, privately owned turbine which, because of its shorter electromagnetic profi le, would be less likely to run afoul of FAA guidelines.
A 10% energy savings for the treatment plant would be signifi- cant. Ouellette said that, in 2009, the plant used 269,000 kilowatt hours of electricity, with the pump stations drawing roughly 100,000 more kilowatt hours, at a current cost of 14 cents per kilowatt hour.
“If it turns out that the town builds a turbine at Ft. Getty, my personal attitude is, we’re not going to stop looking at ideas to increase our efficiency,” Robertson said. “So we’ll have [wind energy developers] come down and make an assessment. If their assessment is, ‘Yes, you could put one up without a FAA problem,’ we would ask the town to consider a proposal for a turbine at the treatment plant.”
A turbine, however, is only one of many additional energy conservation measures that will be suggested to plant personnel in the near future. The source of those ideas is a two-tiered energy-effi- ciency audit that a National Grid contractor is performing for every Rhode Island wastewater treatment plant except Block Island.
Jim McCaughey, environmental manager for the bay commission, noted that National Grid, which funded the first round of assessments, will pay for half the costs of the second round.
“We’re negotiating with the state Office of Energy Resources to get funding for the other half,” he added.
He explained that the idea for energy efficiency audits originated from the Energy Roundtable – a bay commission panel that includes all 19 plant superintendents, along with representatives from Save the Bay and URI.
The panel, established with a $275,000 grant from EPA, was launched in 2008. The grant has helped the treatment plants benchmark their energy use in preparation for the efficiency audits.
Barry Wenskowicz, a pollution prevention engineer with the bay commission, said that the Jamestown facility, which is rated for a maximum flow of 0.73 million gallons per day, “came out better than average for plants its size” in the first-tier audit.
Wenskowicz added that almost all Rhode Island treatment plants are now using a computer program to track their energy inputs – and identify areas ripe for efficiency enhancements.
“That’s the way to get the biggest bang for your buck,” he said. “It’s better than wind and solar. You increase your efficiencies – and then you look at renewables. That’s what we did.”
Wenskowicz was referring to a bay commission announcement that its board had agreed to build three 1.5-megawatt wind turbines to serve its Field’s Point Wastewater Treatment plant. The turbines will provide about 60% of the energy needs at Rhode Island’s largest plant.
Currently, the Falmouth, Mass. wastewater treatment plant has a single turbine sourced from Danish based Vestas. The 1.65-MW unit is “sending electrons directly to our treatment plant and providing 20% of its electricity demand,” said Megan Amsler, who chairs the Falmouth Energy Committee.
Falmouth is planning to build a second 1.65-MW unit for the treatment facility.
Amsler noted that, despite their significant distance from the turbine, the occupants of several neighboring homes – none of which are visible from the base of the turbine – are complaining about blade noise – including a resident who lives about a quartermile away.
To this reporter, the Falmouth prop wash was more audible than it was below the other turbine visited during the tour – but that other turbine, which was also turning in light wind, seemed to be virtually silent.
The turbine that seemed quieter – a 1.5-MW unit sourced from German-based Fuhrlander – is located on the periphery of the former Otis Air Force Base.
The Otis turbine supplies about 25% of the energy required to run nine treatment plants purging toxics from 11 plumes of contaminated groundwater. Doug Karson, a contractor serving as community involvement lead for the Air Force restoration program at the Military Reservation, said that the turbine is expected to save the restoration program about $600,000 a year.
The turbine, which has been operating for about 10 months, has encountered a software glitch that has shut down the unit several times – and Fuhrlander technicians “haven’t been able to nail down the bug so far,” Karson said.
In her remarks on the Falmouth turbine, Amsler said that the Vestas unit had originally been purchased by the state of Massachusetts, and then re-purchased by Falmouth when its originally intended installation fell through. The second Falmouth turbine will also be a previously state-purchased Vestas.
Before the Vestas went up, however, Falmouth encountered a major FAA problem, and its progression is a cautionary tale for Jamestown – which may attempt to challenge the FAA denial of its request to build a 1.65- to 2.0-MW turbine at Taylor Point.
The FAA had signed off on the Falmouth application twice, which led the town to believe that it was safe to pour a foundation for the turbine. Shortly after, the town learned that a third FAA review resulted in a denial – which was not reversed until elected representatives prevailed upon the Coast Guard to raise its minimum descent altitude for the Falmouth approach into Otis airfield from 800 feet to 1,400 feet.
At Otis, Karson said, “The FAA would have definitely denied our turbine request if the Air Force was still there, flying F-15s. As it was, when the Coast Guard came in, they started using a landing approach that was further away than the F-15s were using before.”
Although the Jamestown treatment plant will have to wait for the town’s turbine decision before addressing any FAA issues that might be raised by a turbine proposal of its own, the plant will not wait to increase the efficiency of its energy use.
“It is our intention to implement every potential efficiency enhancement identified by the audits,” Robertson said. “Anything that’s going to save our customers money is something we’ll address – obviously, with the approval of the water and sewer commissioners. But anything that allows us to put cleaner water back in the Bay at less cost, we will pursue.”