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Renewable energy meets conservation: the Hydro House at Hillsborough

Date: 19 August 2019

Author: Christopher Warleigh-Lack

To the very north of the park at Hillsborough Castle and Gardens, for the adventurous visitor prepared to explore the Perimeter Walk, is the Hydro House. Historic Royal Palaces restored and re-commissioned the Hydro House in 2017 and it now produces enough electricity to continuously power 100 mobile phones!

Image: Hillsborough Castle. © Historic Royal Palaces

An exterior photo of the South facade of Hillsborough Castle on a sunny September day. Framed by greenery.

Necessity is the mother of invention

Today we take electricity for granted, but at the turn of the 20th century supply was far from guaranteed. Even in the 1920s Hillsborough Castle did not have access to mains electricity, which stopped a few miles away in Lisburn. The castle, home to the Governor of Northern Ireland, used an unreliable and expensive diesel generator to supply it with power. To counter this problem, in 1926 the Hydro House was built, a small utilitarian building, which was home to a generator powered by water flowing through the gardens of Hillsborough Castle and on eventually to the River Lagan. The Office of Works, the government department responsible for all state buildings including diplomatic and royal residences, commissioned Belfast engineers Robert Craig and Sons to install the generator.

Early problems and decommissioning

Despite its innovative approach, the early years of the project were not without issue, including a series of droughts which rendered the generator ineffective. By 1936 electricity had finally reached Hillsborough, and it was decided to decommission the Hydro House and connect the castle to the mains supply. The workmen who were brought in to dismantle the equipment scattered broken pieces of ceramic (used to insulate the circuitry) and roof slate all over the flower beds rather than cart them away. This caused outrage as the Governor, the Duke of Abercorn, had recently replanted the beds with flowering shrubs!

Ambition and restoration

In 2014 when Historic Royal Palaces took over the care of the site, nothing but a small ruin was left hidden among the trees. We were keen to restore the building, and to follow our ambition for using renewable energy, so in 2017 we completed the restoration of the building and installed a new hydro-generator, which now powers the visitor centre.

In order to restore the building I worked with Maintenance Manager Marc Branagan to establish the history of the building, and how it may have looked when first built. At that point we did not have records of its original construction. This meant going back to original drawings produced by the Office of Works for our other sites, such as Hampton Court Palace. Marc contacted the only producer of 1920s style Crittal windows, and we managed to source replicas.

The original walls were built using interlocking concrete blocks (see image 2) which were experimental at the time for agricultural and industrial buildings, but which didn't really prove popular. Marc was able to recreate these blocks to re-instate the lost sections of wall (see image 1 and 3) and we have now included signage telling the story of hydro-electricity (see image 1 and 4).

The Hydro House in 1926 at Hillsborough Castle.

An Uncanny Resemblance

A couple of years later, we were visited by the son of the original Robert Craig, who seemed to remember something about his father's business working here. Mr Craig Jr happened to find a design for the Hillsborough Hydro House and offered it to us.

With it was a photograph of the building as completed in 1926, looking exactly as it does now, except for the rainwater down pipe being a few feet further to the left - we can't be right all the time!

Dr Christopher Warleigh-Lack
Curator, Hillsborough Castle and Gardens

Image: The Hydro House in 1926. 

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