Selfsufficientish.com

i am lucky enough to have a stream running through my property and want to look into harnessing the energy using a water turbine. i believe there is a formula to work out how much potential your water source has for the job. does anyone on here have any idea of it or where to find it? there is a considerable fall and quite a good flow of water all year around (enough to fill a pipe anyway) and i have done a small bit of reading on alternative energy sources and many sites say that water turbines can be one of the more reliable sources. any info on the subject would be greatly appreciated . . . .

http://www.segen.co.uk/eng/hydro/estimating.htm

That site seems pretty thorough, although it gives the impression its virtualy impossible to do if you live in the UK.

alot of power going to waste with this wet weather

to take this project seriously i need to measure the flow rate when it's at it's lowest, to give me my minimum power output . . . . but with our wet climate here in Ireland it is rare that the turbine would be at minimum output i'd imagine . . . . the advantage of course is that your power consumption is higher during periods when the flow rate (and output) are also increased

Even during low periods, a small hydro system should power far more than you need, even a medium stream 1/2 m^3 with a 1 metre drop would generate 2.5kw, every day, all day.

With that kind of power even electric central heating becomes reasonable, If anything I think you'd struggle to need enough power to make it cost effective.

I'm very interested in hearing about a hydro setup that actualy worked, so if you do go ahead, I'd be very pleased if you could let me know how it works out

I have drolled over these (not that I have a stream or anything)

http://www.navitron.org.uk/category.php?catID=70

DominicJ wrote: If anything I think you'd struggle to need enough power to make it cost effective.

i might but mrs. stonethrower will have no such problems

power (watts) = flow (litres per second) x gravity (9.81) x head (metres)


so, if you have 10 litres per second, and ten metres head, you have 1000 watts. Thats a very low flow, and a good head.

So what have you got?

have about 500l/sec tonight i'd say . . . .

will have to take proper measurements as soon as the flood has washed out . . . . if it ever stops raining

ah - but at what head? 500 l / s is nice - but thats just a slow flow along a river, or one hell of a flow over angel falls....

I'm just about to go out now and do some work on a hydro scheme I installed for a friend using a 'Harris Turbine' and I'm hoping to have my own 'Navitron' turbine up and running this week both systems are high head low flow and there's loads of ramblings on my blog under hydro. It's a bit haphazzard and amatureish but I'm getting there on a tiny budget

Cheers, Paul

was all set to go measuring the head on saturday but was unable to hire a laser level

set about getting a rough guide to flow rate this morning as we have had a couple of dry days and the stream appears to be back to more normal levels.
i make it 45l/sec today
my measurements were a depth of 150mm in a 900mm pipe flowing at 1m/sec (measured over 5m)

reviewing my bills for the last year, we averaged 23.4kwh/day.
i know, iknow, we are leaving an elephant sized carbon footprint

hopefully i can get a laser level this week to get a figure for the head . . . .

am i correct in saying that


23.4kwh/day = (45l/secx9.81m/sec/secxhead)x70% effiicent
0.975kw = (441.45xhead)x70%
0.975 = 309.015xhead
required head = 309.015/0.975
= 317
= 3.17m



prove: 23.4kwh/24h = 45l/sec x 3.17m x 9.81 x 70%
0.975 = 0.9796


my sums are rough looking but . . . . i need about 3.17m head to cover what we are currently using, if the system was 70% efficient, and that is the flow rate

i am confident i have more height than that available . . . . but don't want to guess at it

hopefully i can hire a level this weekend and take an accurate reading,
and if the weather stays dry i can take the flow rate again

Erm, I didnt get that.

Oh wait, yeah I did, silly maths A level

Stonethower - is there any provision for ESB to buy surplus back off you for the grid? The French lot, EdF (for reasons that are lengthy to explain, though I would be happy to do so) are buying spare power off anyone who can make it at some very fair prices.

i am not sure that they will buy surplus from a micro-system,
but if grid-tied will give you credits for your night-time surplus

i spoke to an ESB employee on the subject and he was of the impression that they will in the future be buying surplus alright. interestingly, he had very little time for the solar panels that are being installed on new houses in this country at the moment . . . . no payback he reckoned . . . . but he did seem to think my turbine project was worth pursuing