Suggestions to get the most out of the area’s proposed $1.2-billion sewage treatment system are spinning at the Capital Regional District.

The CRD is contemplating placing turbines inside its wastewater pipes to generate electricity from the passing rush of water.

It’s an idea taking form within the water department, which is seeking proposals from the private sector to implement the same technology at the Humpback Reservoir.

“We are going to put a turbine at that location,” confirmed CRD water services general manager Jack Hull. “So rather than wasting the energy in a pressure-reducing valve, we would be able to generate electricity from it.”

The turbine would produce 500 kilowatts of electricity, which would then be sold to BC Hydro, Hull said.

The District of West Vancouver has a turbine up and running, having installed the European technology as part of a pilot project. The unit has kind of an “old waterwheel” inside, said Raymond Fung, West Van’s engineering and transportation director. “The technology is very, very simple. It really is sort of like a pinwheel that kind of spins around, moving because the water displaces the paddles,” he said.

The sewage treatment system’s turbines would be bigger. Based on calculation of placing a large plant in the Macaulay/McLaughin area and smaller distributed facilities in the West Shore and Saanich East, 40 per cent of the wastewater’s potential energy flow could be recovered, according to a CRD discussion paper on Flow Energy Management and Pressure Recovery.

“Any opportunity where there is an elevation change and you have flow through the pipe, whether that is water or wastewater, there is the opportunity to put it through a turbine and generate electricity,” said Dwayne Kalynchuk, CRD general manager of environmental services.

The turbine would produce 305 megawatt hours (MWh), climbing to a peak of 540 MWh as volume grows by 2065, the paper predicts.

A typical British Columbia household uses approximately 10 MWh of electricity per year. The proposed wastewater turbines could supply between 30 and 50 households with power for a year.

raldous@vicnews.com