A new hydropower turbine in a south Seattle water district’s water main aims to generate roughly 70 percent of the annual energy consumed by the district’s administrative facilities.
McKinstry, with the cooperation of Gray & Osborne, partnered with the Covington Water District to install the new turbine, which began operating in October to capture previously wasted energy. The turbine system, custom manufactured by Washington-based Canyon Hydro, was installed in a new water transmission line that connects the water district to Tacoma Water. The 170-ft drop between the Tacoma Water source and Covington Water District’s system causes substantial pressure buildup. Originally, a pressure-reducing valve handled the pressure, but that caused energy loss in the form of heat and noise. The new turbine reduces the water pressure while generating energy.
“Covington Water District needed to build the new water line anyway, so we wanted it done the right way, focusing on innovation and sustainability,” said Thomas Keown, general manager at Covington Water District, in a statement. “Not only will the turbine reduce our energy costs by supplying 70 percent of our administrative site’s power, but we will also cut energy waste by using this new, efficient technology.”
Along with capturing energy otherwise lost, the project also reduces the need to run well pumps to pull water out of the ground. The turbine will run continuously and McKinstry plans to verify the system’s performance and guarantee the energy savings for the term of the performance contract.
“Efficiency and innovation were Covington Water District’s focus for their new pipeline,” said Andrew Williamson, McKinstry’s municipal business manager, in a statement. “We built a great team that pushed sustainability while understanding the need to be able to advance water flow and net energy metering. We provided the turbine to generate power in place of a conventional pressure-reducing valve, taking advantage of the district’s new transmission line that was required to address system resiliency.”
A grant from the Washington State Dept. of Commerce covered 25 percent of the project cost. The Covington Water District turbine project was $376,749 for turnkey delivery of the turbine portion of the project.
McKinstry plans regular follow-up inspections to ensure the turbine meets operational and energy savings expectations.
Follow Tim Newcomb on Twitter at @tdnewcomb.