Still generating strongly, though now down to 1 turbine through summer months. Thought about changing the nozzle size, but dont think the difference will be that significant. The power output is slightly down from what it once was per turbine, now about 440W, whereas about 500W was possible initially. I think this may be signs of bearings beginning to need changed, but reluctant to do overhaul until the output drops more significantly. noise been an issue, due to closeness to house (approx 50m), and outside hut reads about 65db, but it seems to be the nature of the frequency that carries the sound, like a constant hum in background. Have severely insulated the internals of the shed with noise insulation foam, polystyrene and planning to use more expanding foam between floor and ground. Additionally, created log stack to act as wall between house, but still the sound persists at low level. Anyone, got any good ideas, would be interested to hear. The other idea was to try create some background noise off the burn with a small waterfall or something…
Pico Hydro project
Record of small scale hydro project in Scottish Highlands
Pico Hydro project 
Could some of the noise be coming from the exhaust? If so, keeping the tailrace pipe submerged would help.
Thanks for help, though We have tried submerging exhaust, slight improvement
Hi There,
With reference to the noise issue I saw a Grand Designs once where a Wedding venue was being built and the walls were built from soil to reduce the noise levels the planning authority had set. You could bank up soil onto the walls of the turbine shed and maybe a turf roof?
Another idea would be to plant a dense hedge such as holly around the shed. It may reduce sound levels by a few dB.
Another solution is an active noise cancelling device which produces a frequency which cancels out the noise. A bit like noise cancelling headphones. I have no idea if this crowd are any good but may be worth a try.
Here is a site
http://www.silentium.com/?page_id=364
kind regards
Julian
Thanks for advise, i think soil may help, but would be a last resort as would make the nice quaint shed look a bit bodged. We have planted quite a few shrub type bushes and there is a roddy nearby that blocks a fair bit.
I did look into active noise cancelling, but couldn’t locate any useful (affordable) suppliers/solutions.The link you provide looks interesting though, will make enquiries as to costs… power consumption