There is a small stream (or is it a beck or a brook?), about 40 metres long; descending about 5 metres, running along one side of the hovel. We have already decided to install solar panels on the roof. Everyone knows “it is always sunny in Reeth”. But the sun is not always as bright as the Costa Brava or the Highveld in South Africa. Very occasionally, particularly in winter, there is a cloudy day or two.
Intrigued by the possibility of generating power from the brook. I investigated micro-hydro systems. Rainfall is higher in winter, so I guesstimated that hydro power might compensate for less solar power in winter. Hydro also provides power 24/7 365 days a year. The video below shows the brook overflowing in May 2024.
A very long time ago I completed a Geography degree and vaguely remembered measuring water flows in a river with a tape measure and propeller on a stick. There is a useful video explaining this by the ‘Geography Men’ on YouTube https://www.youtube.com/watch?v=M1Tb7HsEtOM
Knowing water flow (in cubic metres per second) is important for estimating how much energy might be generated. It also helps to estimate the size of pipes required to take (some of) the water flowing in the brook to a turbine. The size of turbine required is also determined by water flow.
One of several problems is that water flow varies by month and by year. I therefore bought a propeller on a stick thing and decided to take measurements throughout the year. For six months, since January, I have been measuring water flows. I will continue until January 2025.
I take reading every time I stay at the hovel, see the blue numbers in the spreadsheet below.
I’ve also used UK government Environment Agency data to record rainfall data for 24 hours, 48 hours and the week before readings were taken, see the black data to the left of the spreadsheet. Flow in the nearby River Swale was also recorded as a further benchmark. The Environment Agency also provide historic data since 1990. Interestingly this shows that summer flow rates are about 60 per cent of winter flows. The decrease in power in the summer might not be as large as I had expected.
Finally, using various formulae, on the right of the spreadsheet (in green) calculations are made for average flow, power created and energy generation a year. Calculations suggest generation from micro-hydro might produce 60,000 kWh a year. In the UK an average five bedroom house consumes 22,000 kWh a year. This seems too good to be true (I've checked the method and calculations several times). For comparison household solar systems produce about 5,000 kWh/year.
This will be a pet project when building work is completed. But I’ve already ‘got my eye on’ a stream engine. There is wonderful video on YouTube of a Canadian 'off-grid' family using the micro turbine in the wilds of Canada https://www.youtube.com/watch?v=XyWQ3o6plY8
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