Duke's hydro system taps into the past

AN ancient hydro-electric system which has not been used for more than 50-years is being restored to power the Duke of Northumberland's estate.

The 105,000 project, due to be complete early next year, will help reduce carbon emissions, and is expected to produce around 25KW of electricity – roughly equating to the average daily usage of 20 modern houses.

The first hydro system was installed at Alnwick in 1889 by the Sixth Duke and was updated in 1938, before being decommissioned in 1948 when the Castle turned to mains electricity.

But now, more than six decades later, Northumberland Estates is turning back the clock and returning to the old technology.

Graham Caygill, clerk of works at the Estates, said: "The Estate is keen to play its part in the cutting of carbon emissions by researching renewable energy options.

"It is now commonly recognised that grid connected renewable energy will be used to first displace that supplied by high carbon emission coal-fired plants.

"It is expected that our hydro-electric scheme could therefore save around 65 tonnes of coal fired CO2 emissions per annum."

The original turbine was found to be in good condition considering its age and lack of recent usage and is being restored by mini hydro engineering specialists, Derwent Hydro, based in Derbyshire.

The existing powerhouse and turbine are also being restored, with a new modern generator fitted in the powerhouse.

The Alnwick system produces power from a water turbine located adjacent to Cannongate Weir on the River Aln, in Hulne Park.

In the original system it is thought the cable supplying the power to the Castle ran down Cannongate through the coping stones on the Castle wall, crossing the road at the Lion Bridge. A bank of batteries stored the power.

Mr Caygill said: "It is well over a year since work began on the restoration of the hydro-power scheme.

"The project commenced with the digging out and clearance of the water inlet. The turbine is now undergoing restoration work, and if all goes to plan, the project should be completed early 2010."

A special filter will stop fish from entering the system and if water levels become insufficient, the system will shut down.

The electricity produced will be transmitted via a private main to the Estate workshops where it will be used and any surplus sold back into the National Grid.

As a producer of renewable power, Northumberland Estates will also receive Renewable Obligation Certificates (ROCs), which can be traded to offset the project's 80,000 cost and 25,000 connection fee.