Wet winter boosts hydro production

Heavy snow in the Sierra last winter is paying financial dividends for Truckee Meadows Water Authority customers this summer.

TMWA, which operates three small hydroelectric plants along the Truckee River west of Reno, has generated more than enough electricity to offset its power requirements.

A big factor was runoff from the Sierra snowpack, especially because the flow down the Truckee remained strong well into the summer, says Pat Nielson, manager of distribution maintenance and generation for TMWA.

"We had a banner year," he says. "The water was available at the right times this year."

The hydro plants delivered about 45.9 million kilowatt hours to the NV Energy system. That's roughly 2 million more kilowatt hours than the amount of electricity consumed by TMWA.

NV Energy, which uses the hydro power to offset a portion of a state requirement to rely on renewable sources for energy production, credits its purchases against TWMA's power bill.

Flows along the Truckee River were topping 600 cubic feet a second last week, well above the 500-cfs average this time of year. That's maintaining power production deeper into the season, Nielson says.

While the long runoff season was a major factor in TMWA's strong hydro production, Nielson says the water utility also is reaping the benefit of a years-long effort to modernize the three hydro plants.

The plants were built by Sierra Pacific Power Co. in 1904, 1905 and 1912.

TMWA took them over when it purchased the water utility operations from Sierra Pacific in 2001.

At each of the hydro plants, water is diverted from the river into a flume to spin a generator and back into the river. (The water rights for the plants are among the oldest on the Truckee.)

TMWA also has benefited from operational improvements that have reduced its power consumption meaning that hydro power can meet a larger portion of the utility's needs even in years without big snowpack.

A big reduction in pumping costs came with completion of improvements to the gravity-fed Highland Canal, which delivers as much as 95 million gallons of water a day to the Chalk Bluff treatment plant just west of McCarran Boulevard near Fourth Street