A renewable energy scheme to power buildings in Alnwick is reaping the benefits.
In 2010, the Duke of Northumberland officially unveiled the restored hydro-electric system on the River Aln.
Three years later it is still being used and is powering buildings in Hulne Park.
The system produces power from a water turbine located adjacent to Cannongate Weir on the Aln.
The £105,000 project saw a system which hadn’t been used for than 50 years being refurbished.
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.
The original turbine was found to be in good condition considering its age and lack of recent usage and was restored by mini-hydro engineering specialists, Derwent Hydro, based in Derbyshire.
The existing powerhouse and turbine were also restored, with a modern generator fitted in the powerhouse.
A spokesman for Northumberland Estates said: “The Northumberland Estates restored and modernised an Edwardian hydro-electric system in Hulne Park in 2010 and, since then, the system has successfully provided environmentally friendly electricity.
“The system generated 31,007 Kilowatt hours of electricity in the period between January and July 2013 – the equivalent of nearly 17 tonnes of coal.
“The generator is linked to the natural flows of the River Aln so will have produced less in the recent dry period, but electricity generated is used to power buildings in Hulne Park and any surplus is then returned to the national grid.”
But plans for an energy plant at Lionheart Enterprise park have been put on hold.
The Estates was looking to build a £6million scheme, with a combined heat and power plant fed by a relocated sawmill.
An application was put in to Northumberland County Council in November 2011.
A spokesman added: “Our plans to build a combined heat and power facility on the outskirts of Alnwick are currently on hold but, as a supporter of sustainable energy initiatives, the hydro-electric system is particularly advantageous because it does not change the aesthetic of the beautiful Northumberland landscape and has no detrimental impact on local wildlife.”