Addition of Hydroelectric Facility to Pressurized Water Supply Pipelines

Tarrant Regional Water District (TRWD) is a major raw water supplier to the Dallas-Ft. Worth area in Texas. As with many other municipal water systems, TRWD’s infrastructure provided a potential source for significant hydropower.

Arlington Outlet is a case in point. The outlet is located on three parallel gravity pipelines between a balancing reservoir and a water treatment plant. With a design capacity of 200 million gallons per day (mgd), it is used as a discharge point to supply Lake Arlington. Pressure-reduction valves at the outlet had been burning about 154 feet of head, or pressure, to dissipate energy prior to discharging into Village Creek, which flows into Lake Arlington.

Black & Veatch assisted TRWD, providing permitting, engineering, construction management, and commissioning services, to take advantage of the wasted energy by adding a new hydroelectric turbine generator at the Arlington Outlet.

Allocated Energy

Black & Veatch designed the project to optimize the use of a turbine generator system to a flow of 80 million gallons per day with 154 feet of head. This allowed TRWD to operate the turbine system consistently by scheduling water deliveries to Lake Arlington when required, bypassing any additional flow to the pressure-reducing facility. In this manner, significant energy previously lost through pressure reduction is now being recovered and provided to the local electrical grid when additional electricity is needed most by the local community.

Taking advantage of Arlington Outlet’s close proximity to an urban area as well as its existing head and kinetic energy, the 1,350-kilowatt hydropower facility is expected to deliver about 6.5 gigawatt-hours of energy annually.

In addition to qualifying for renewable energy credits, the facility is reducing the impact of water supply operations on the region’s power consumption. The Arlington Outlet Hydropower Project is an important asset that demonstrates TRWD’s commitment to the sustainable use of its existing resources.