Case Study - High Head Hydro

Benlister Hydro

Benlister Burn, Isle of Arran

The Benlister Hydro Scheme is located on the Benlister Burn on the Isle of Arran. The scheme lies within the Arran Moors Special Protection Area (SPA).

Green Cat Renewables provided post planning management, detailed scheme design, technical procurement services and Client’s Engineer services.

The key elements of this project are:


The scheme has 2 intakes which divert water to a main collection intake where the pressurised pipeline starts.


The aqueduct pipelines are a total of 675m in length. The pipeline from the main intake to powerhouse is 3,125m long. The upper, low pressure section is of HPPE and the lower, higher pressure section ductile iron (DI). The pipeline has an above ground, pipe bridge, where it crosses the Tounie Burn.


The powerhouse is designed to be a steel portal frame with concrete block infill. Planning conditions required that the roof is covered with grey profiled tin and external walls are clad with vertical larch timbers. The acoustic doors will ensure that sound emissions are kept to a minimum.


An access track used during construction will continue to provide access for maintenance. Its reinstatement to a vegetated running surface will substantially reduce the long term environmental and visual impact of the scheme.


The construction phase successfully incorporated seasonal working restrictions in relation to Hen Harrier’s in the area.

Key Data
  • Client: Glenkiln Hydro LLP
  • Power: 500kW
  • Gross Head: 267m
  • Maximum Flow: 244 litres/second
  • Turbine Type: Twin Jet Pelton
  • Predicted Average Annual Energy Production (AAPE): ~1,570 MWh
  • Pipeline: 3.5km
  • Two pipe bridges
  • Special Protection Area
  • Date of Commissioning: July 2016