Dowally, Perthshire, Scotland
The Dowally scheme is located on the edge of the A9 to the south of Pitlochry, on the Atholl Estate. The Estate construction this scheme in tandem with a fellow identical turbine which is installed again next to the A9 but closer to Pitlochry.
The intake was an existing redundant water supply weir, which was modified to suit. A 2km pipe transfers water from the intake to the turbine house which is situated close to the A9. This provides a Gross Head of 153m. The pipeline is HDPE (High Density Polyethylene)which was chosen as the most suitable.
The turbine used in this scheme was chosen to be a Gilkes Twin Jet Pelton operating at a design flow of 390l/sec and a speed of 1000rpm. This turbine is an impulse turbine which is optimized for high-head applications and provides high efficiency across the full range of flows.
Using this turbine it is possible to produce 496kW of power. The scheme is grid connected and all power produced is exported. The average annual energy production ("AAEP”) is 2000MWh and the scheme is to benefit from the UK Feed In Tariff ("FiTs”) subsidy mechanism.
The lead consultants on the scheme were Interhydro Technology and main civil contractors were Askams. The scheme secured many local jobs during its 18 month design and construction phase and the income from the scheme will contribute to the ongoing upkeep of the Atholl Estate.
Along with providing the Electrical & Mechanical ("E&M”) equipment, Gilkes, via their financing subsidiary, Gilkes Energy, provided a financing package. The package reduced the initial funding requirement from the Estate and is linked to actual electricity generation. Gilkes and the Estate are therefore long-term financial partners and share the risks and rewards of the project.
- Gross Head = 153m
- Net Head at Design Flow = 146m
- Flow = 390 l/sec
- Turbine type = 650 P316 Twin Jet Pelton
- Output power = 496kW
- Average Annual Energy Production = 2000MWh
- Load Factor = 50%