Gilbert Gilkes & Gordon Ltd
Sherard Water Treatment Plant, USA
Sherard Water Treatment Plant, USA
Key information
- Commissioned: 2023
- Turbine Type: Vertical 4 Jet Pelton
- Power: 867 kW
- Head: 149 metres
- Flow: 708 l/s
Gilkes Scope of supply
- 650mm Vertical 4 Jet Pelton Turbine
- Synchronous Generator, 950kVA, 480V, 720rpm
- Hydraulic Control Module
- Main Inlet Valve – DN400 PN25 Butterfly Valve
- Electrical Package
- Installation & Commissioning
Ground breaking on the Sherard Hydroelectric Facility started in 2021, with a purpose-built powerhouse at the Sherard Water Treatment Plant, west of the City of Cheyenne in Wyoming, USA. The Turbine is powered by raw water pressure that flows from Cheyenne’s water supply coming into the plant. The energy is primarily used to power the treatment plant, which typically consumes 200 to 400 kilowatts, any remaining power will be sold back to the grid.
Gilkes designed and built the 867kW Vertical Four Jet Pelton turbine for the project. During the turbine selection process Gilkes engineers originally offered two alternative machines, a horizontal twin jet machine and the vertical shaft four jet unit which the customer selected. The selected machine was a slightly lower cost option with higher annual energy production.
The customer had specified that an impulse turbine should be used even though the head was less than 500 ft (152m) because of the ability of impulse turbines to minimise surge effects when the flow is altered. A Francis turbine would produce less energy because of the range of flows and would cause dangerous pressures if the unit tripped.
The plant is a typical energy recovery scheme. Untreated drinking water from the City of Cheyenne reservoirs is collected and passed at flows of up to 25 cfs (0.7 m³/s) through 15 miles of pipeline to the Sherard Water Treatment Plant where it is treated and distributed around the city. Between 1975 when the WTP was first built and the commissioning of the turbine in 2023, the city had used pressure reducing valves (PRVs) to remove the excess water pressure. This was effectively wasting over 800 kW of power and over 4 GWh of energy every year.
