Water power works in North York Moors
Water power works - and one family in the North York Moors is doing their bit to prove it.
Trudy and David Sanderson live at Bonfield Ghyll Farm, Bransdale in a remote part of the North York Moors. Their 135-acre National Trust-owned farm is seven miles from the nearest village, Helmsley, and in a valley totally surrounded by moorland.
They have no neighbours, no mains gas, no mains water and no mains electricity.
They're as off-grid as it's possible to be, but they don't lack a cheap, green supply of power thanks to the stream that powers a generator and some tried and tested technology.
Read on to find out how the family - with six children aged from two to 17 - power their lights, TV, computer, freezer and washing machine... all with green, renewable energy.
Bonfield Ghyll Farm, North York Moors
In January 2007 an Archimedean Screw hyrdo generator was installed at the farm to provide electricity for the Sanderson family. Before this, all their electricity came from a diesel generator.
The project was jointly funded by the North York Moors National Park, the Sustainable Development Fund and the National Trust.
When the Sanderson family moved into the farmhouse, originally built in 1707, on the 135-acre farm in 1995 there was no central heating. Mum Trudy Sanderson had a toddler and a 13-week old baby at the time.
Not only was there no electric kettle, toaster or cooker but there was no washing machine or tumble drier either.
Trudy says: "At the end of the first week I almost cried. But after the initial shock you just get on with it.
"During the day we tried to live without electricity because it was costing so much to run. Then in the evening we had a few frantic hours when I used to run around with the vacuum cleaner.
"We used bottled gas for our cooker but I never had a freezer because it would have been too expensive to run the generator for enough hours.
"When it was running the generator was quite noisy - it sounded like a car engine ticking over all the time. You could always hear it, and you could almost see the pollution and we could always smell it.
"It was expensive. It wasn't just the cost of the diesel, it was spare parts for the generator, oil filters and all the maintenance too."
The family now has free, green electricity. There's enough power for their TV, computer, lights, a washing machine and, at last, a freezer!
Says Trudy: "People who are on mains (electricity) just flick the switch and don't think about it. Now we've got free electricity and I like the fact that it's greener than being on the grid too.
"We've had plenty of power since the screw was installed. Only once in the last three years have we had to go back to using the generator as a back up and that was during a dry spell. I had to put the generator on for an hour once every couple of days.
"Generally the power has been plenty. On a good day we've had about 1kw per hour from it - sometimes we've had to put the electric fire on just to use up the surplus energy!"
How they did it
The stream which runs past the farmhouse made hydro power seem the obvious choice for power generation but the shallow gradient of the stream initially caused problems.
It was only when the Archimedean Screw technology became available that hydro power became viable for the Sandersons - the screw only needs a two-metre drop to be effective.
Trudy's husband Dave dammed the stream by placing old corn bags filled with sand from the river and covering these with stones from downstream.
He then dug a simple channel towards the bank where the device would be situated, 20-metres from the farmhouse, with the help of a hydroengineer. This took two days.
The channel was lined with plastic sheeting (no need for concrete) and the screw was dug into a bank and covered over (apart from a glass viewing panel).
A control box, 240-volt inverter and batteries to store power generated by the technology were installed and tested.
Costs and savings
For more information on mini hydro schemes see the British Hydro Organisation's guide: