Sherard Hydroelectric Facility
The Vertical 5 jet Pelton turbine produces enough electricity to power the City of Cheyenne's water treatment facility
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ENERGY RECOVERY
Energy recovery in the context of hydropower is the extraction of the potential energy of flowing water from a pressurised water source, usually already in existence for pre-prescribed purposes.
Examples of the pre-prescribed purposes include, but are not limited to;
- Transfer of water from one reservoir, tank, holding source, to another
- Conveyance/transfer for municipal drinking water delivery
- Conveyance/transfer of raw water to water treatment facilities
- Waste water treatment applications
The above types of conveyance or transfer occur typically under a gravity fed scenario through a network of large and medium diameter pipes, or aqueducts, but can sometimes be pumped applications. In any case, pressure builds from the higher elevation to its lower point of distribution and needs to be reduced prior to entering either a water treatment plant or a municipal distribution system.
In the majority of situations, the pressure at the point on treatment or distribution is reduced by the means of a pressure reducing valve or PRV. These valves destroy the potential energy of the water that has built up in the pipelines and reduces it to an acceptable pressure level for commercial and household distribution. These PRV’s consume energy in terms of the electrical power required to operate it.
Advantages of energy recovery using hydropower
- Energy Generation from an Existing Process
- Reduces Environmental Impact
- Turbine as a Flow Control Device
- Replaces Pressure Reducing Valve Function
- High Efficiency and Reliability
Gilkes Solutions
Gilkes offers solutions whereby the potential energy that was once destroyed can be utilized for power production.
Gilkes has a range of turbines that can be optimized to a specific site to harness the potential energy of the water and turn it into electricity, utilizing either a reaction or impulse style of turbine. Where downstream pressure is required, or a turbine is fitted within a pressurized system, a Francis (reaction) turbine is the preferred choice. If the turbine can discharge to atmosphere, then a Gilkes Turgo or Pelton turbine can be installed. The Gilkes Turgo is ideally suited to and is often installed at the head of a water treatment facility where it can be utilized to control flow through the facility as well as generate power at the same time.
The electrical power that is produced by our turbines can be used in a number of different ways;
- The electricity can be used to power a water treatment/wastewater treatment facility to offset their annual energy consumption in a ‘behind the meter’ application
- The electricity can be sold directly in the grid with the means of a power purchase agreement
- If more power is produced than can be consumed, a combination of behind the meter and export to the grid can be achieved
In all scenarios, water delivery is paramount and energy recovery a secondary function. To ensure the safety of the treatment plant or municipal headworks, the turbine will almost always be placed in parallel with a PRV to ensure that if either is offline for any reason, water can still be conveyed as needed for processing or delivery to consumers.
South Australia Water Project in Australia
The Seacliff project is an example of mini-hydro equipment within a desalination plant, as part of SA Water’s North South Interconnection System Project. Read the full case study below.
