This July, staff and volunteers at the National Trust’s Cragside in Northumberland, are celebrating the one year anniversary of the return of hydropower to the former home of Victorian engineer William Armstrong.
This month, the 29 July marks one year to the date since local Geordie actor, Robson Green, officially switched on the Archimedes screw at the property in Rothbury, Northumberland - relighting the house, just as Lord Armstrong did back in 1878, with water.
Cragside was the first house in the world to be lit by hydroelectricity, when Lord Armstrong used water from the lakes on the estate to generate electricity through a turbine. His friend Joseph Swan provided the light bulbs to light the house.
The introduction of this modern hydro system - a 17 metre long galvanised turbine weighing several tonnes – meant it once again began to produce enough energy to light the bulbs in the house, enabling Cragside to re-tell the story for which it is famous.
At the beginning of July, the Archimedes screw had produced exactly 13669 kWh of electricity, which is almost enough to run electricity in three average sized homes for a year. This is enough energy to light all of the lights in the house - which is no mean feat. The average home has 24 light bulbs; Cragside House has over 350 of them!
To make this system as efficient as possible, Cragside is fitted entirely with LED lightbulbs – as each bulb is only 5 watts, it takes only 2 kWh in total to light the house, fulfilling and continuing Lord Armstrong’s dream of lighting his home entirely with hydroelectricity.
Andrew Sawyer, Conservation Manager at Cragside, commented:
“Lord Armstrong was an exceptional man with an ingenious mind and bringing his vision for Cragside into the 21st century is a dream come true. Hydroelectricity is the world’s most widely used form of renewable energy, and it’s fantastic for us to be able to share this very special part of its heritage.
“The Archimedes Screw is a very visual demonstration of the way hydro power works, an almost sculptural sight in the landscape.”
The Archimedes Screw is a centuries old system, more commonly used today to generate electricity. However the design of the Archimedes screw, attributed to Archimedes of Syracuse on the 3rd century BC, was originally used to lift water up an incline.
More recently, scientists and engineers determined that it is possible to produce electricity by letting water drop through the screw. These ‘reverse’ Archimedes screws are now fast becoming a popular form of a micro-hydro generation in places such as Cragside.
Water from Tumbleton lake, the lowest of the five lakes on the Cragside estate, feeds through the turbine and into the burn below. As water passes through the spiral blades it causes the screw to turn, thereby harnessing the energy of falling water; quite literally turning water into electric light.
The water enters the screw at the top and the weight of the water pushes on the blades of the screw, allowing the water to fall to the lower level and causing the screw to rotate. This rotational energy is then harnessed by an electrical generator connected to the main shaft of the screw turbine.
The technology is well proven with over 100 installations in Europe and was chosen by the National Trust in 2014 for its many advantageous features.
The electricity the screw produces is fed directly into the house supply. It also contributes to a further 5‐10% of energy in the region now being sourced from a renewable energy.
Sarah Pemberton, Head of Conservation at the National Trust explains:
“The hydro-turbine is a great example of the innovative methods the National Trust is employing in order to achieve the highest possible standards of sustainability. The Trust has committed to using 20 per cent less energy and to generate 50 per cent of our energy from renewable sources by 2020. The Archimedes screw at Cragside is another step in this direction, and helps one of our biggest properties in the region to generate its own electricity.”
If you’d like to find out more about the story of engineering at Cragside, you can join the property’s engineer, Robin Wright, on an engineering walk. The next one is due to take place on Wednesday 5 August, and will be a special family version suitable for children from age 4 and up.
Or, you could join Conservation Manager Andrew Sawyer for his upcoming talk “Just add water: the Archimedes Screw” on Friday 7 August, where he will be telling the full story of how hydroelectricity was brought back to Cragside.
Find out more about events at Cragside at www.nationaltrust.org.uk/cragside