Fall Creek Hydroelectric Plant
The first electrical generation facility in Fall Creek gorge was built in the early 1880's. That plant was powered by water from a dam just above the present dam, with a water wheel just above the present plant with a cable to a generator located near the Foundry. In 1904, the present plant was built. Construction was preceded by replacing Triphammer Dam slightly west of it original location in 1896. The water source is Beebe Lake. Water is supplied to the plant by a five-foot diameter underground penstock, 1700 feet long. The existing intake dates to 1953 and was upgraded in 1981.
The original plant capacity was 300 kW. Improvements in turbines, intake, and controls were made three times--in 1913, 1935, and 1957--allowing the same basic plant to produce almost triple the electricity -- about 850 kW. The 850 kW plant continued to operate until it was temporarily abandoned in 1970, a period of historically low energy costs.
Hydroplant turbines
In 1981, the plant was completely renovated. All the original machinery was removed except for one of the DC exciters. Two Ossberger crossflow turbines were installed with a total rated capacity of 1,900 kW. The plant, however, is limited to about 1,100 kW output because of the size of the penstock.
This hydroelectric plant is "run of river", which means that no water is stored. At all times, 10 cubic feet per second (cfs) must continue to pass the dam, to maintain a healthy creek aquatic ecosystem.
In 2007 the first phase of an effort to increase the plant output and reduce operating costs was completed by installing digital controls. Production has increased approximately 20% due to improved unit modulation with the creek flow, increased production at very high flows with 2-turbine operation, and the ability to operate the plant during very low summer flows.
Future phases to increase production will focus on reducing losses at the intake structure, installation of draft tubes, and/or increasing the diameter of the penstock.
The plants supplies about 2% of the Ithaca campus electricity.
For more information, contact Frank Perry, Hydroplant manager: fdp1@cornell.edu.
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