A Hydroturbine From Hydra Engineering Saves Power Costs For A Small Oregon Water Plant

A small Oregon water treatment plant breaks new ground with a custom-built hydroturbine that saves on electricity costs.
A Hydroturbine From Hydra Engineering Saves Power Costs For A Small Oregon Water Plant
Jm Jans (left), manager of the Corbett Water District, with David Jacob, owner of Hydra Engineering and designer of the district’s hydroturbine.

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Operating costs at the Corbett (Ore.) Water District water treatment plant were steadily increasing, and rates rose accordingly.

Jim Jans, district manager, saw irrigation systems and some larger wastewater treatment plants using hydroturbines and wondered why his district couldn’t use a smaller version of the technology to help reduce the cost of water distribution. “I learned that the Federal Energy Regulatory Commission prohibited the installation of hydrogenerators on municipal drinking water mains,” he says. “I refused to accept that reasoning.”

Numerous obstacles and extensive paperwork took eight years to resolve, but the commission finally granted approval in 2013. David Jacob, owner of Hydra Engineering in Welches, Ore., designed the 24-inch-high, 15 hp hydroturbine based on the plant’s total dynamic head and hydraulic flow. Since it went online in February 2014, the district hasn’t paid an electric bill.

Size is everything

The 1.4 mgd (design) plant delivers 500,000 gpd in winter and 1.2 mgd in summer to a population of 1,080. Water from an intake on Gordon Creek flows 2 miles down a 10-inch pipe at 180 feet of head, delivering 900 gpm to the plant. A CLA-VAL valve reduces the 90 psi pressure as water flows to a weir that distributes it to three sand-and-gravel filter ponds. After chlorine addition, finished water is piped into a million-gallon storage tank for distribution.

“Our small size was David’s biggest stumbling block in designing the turbine,” says Jans. “He couldn’t recommend anything off the shelf as it could have too high an rpm or oversized piping.” A New York company built the turbine.

While waiting for its arrival, Jans wanted to build a 4- by 8-foot building for the hydro components. “City hall didn’t know how much a building permit for a hydroelectric plant would cost,” he says. “The district electrician charges $92 to inspect a 20-amp circuit, which we would install, and that became the cost of our permit.”

Jans ordered a waterproof fiberglass building from Power Design in Odell, Ore., saving $10,800 by not hiring a contractor to build a wooden structure. Then he and utility operators Jeff Busto and Hans Rathjean framed and poured a 4-foot-square concrete pad for the building 8 feet from the weir.

Power preparations

They dug a 320-foot-long trench from the treatment plant to the pad and laid three electrical conduits. “One powers the lights, fan and heater in the hydro building,” says Jans. “Another carries the power we generate to Portland General Electric Power’s two-way net meter, and the third is for when we build another turbine.”

Plumbing included an 8-inch pipe from the weir to the pad, a fish screen designed by Farmers Conservation Alliance on the Gordon Creek intake and a Y-strainer at the pressure-reducing valve. Both screens have 3/32-inch holes to keep out fish and gravel. “Emulsifying fish in the turbine was a major concern for our local Department of Environmental Quality representative,” says Jans.

The team also installed two tees with motorized butterfly valves to channel water to the turbine or filter ponds. Two electronic gate valves split the incoming flow to a jet on either side of the turbine. After water hits the fins and spins the motor, it drops out of the bottom to a diverter box below the pad for dispersal to the ponds. The plant’s RSView32 SCADA program (Rockwell Automation) controls the system.

The pressure-reducing valve used a lot of energy. With the new arrangement, it is on only when the turbine is off. “Our monthly electric bill was $400,” says Jans. “Since we activated the turbine in February 2014 we haven’t had one.”

Other components

The 250-volt DC generator, running at 1,500 rpm, generates 10 kW at 15 amps. Two inverters operating in master-slave mode convert DC current to AC current compatible with the power grid. In the event of a utility power failure, the outage triggers an alarm and switches the inverters to send power to large heat sinks.

“Telemetry notifies us and we switch off the turbine until PGE restores power,” says Jans. “If we transmitted power while PGE was down, we could electrocute a lineman.”

The turbine averages 50 kWh per day more than the plant’s usual requirement of 100 kWh. “In seven months, I’ve put 3,000 kWh in the bank through PGE’s net metering program,” says Jans. “At the end of our yearly cycle, the utility keeps it to help low-income families afford electricity.” The $4,800 the district saves annually by not paying electric bills helps offset the cost of upgrading the distribution system.

Made in the USA

When the turbine arrived, Jans noticed many foreign parts. A quick search on the Internet revealed no U.S. substitutions. “The 3- by 3-inch inverter boxes weren’t very robust,” he says. “We pulled them out and had Canyon Hydro in Deming, Wash., rebuild and modernize them to avoid trouble down the road.”

Replacement of the capacitors and relay switches came next. In January 2015, Jans shut off the turbine, enabling Canyon Hydro to replace the remaining foreign components. “I want an all American-made turbine,” he says. “My next goal is for Canyon to manufacture spare parts for everything, including the electric motor, then put them on my shelf.”   



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