We have a Proven 6KW wind turbine installed towards the end of 2006. It worked well for 6 weeks when the turbine head fell apart in a big way.

Four months later we had a new turbine and new blades and for just over a year things were fine. We generated about 8000KWH during that time, which, while less than the sales pitch, was perfectly acceptable. We had an independent installer round for servicing and he advised that he would be surprised if we got less than 10000KWH per year, so our site location is clearly not bad.

Then in July 2008 we had a major electrical failure. This turned out to be a known overvoltage issue. Four months later all the electrics were replaced along with 3KW heat dumps to prevent overvoltage in the future. We had two 2.8KW inverters on loan as a 6KW unit was not available. Over the next 12 months we generated only 4000KWH. This was obviously a disappointment and I was advised by Proven that the two smaller units would be less efficient and hence my lower generation.

Eventually, we managed to get a replacement 6KW inverter and after many replacement chips and reprogrammings of said chips, we appeared to have a working system again with all the overvoltage protection built in! I couldn't be happier. Seven months on and we appear to be heading towards an annual generation of between 2500 and 3000KWH!!

So each time Proven 'fix' my system my output is approximately halving. Is it possible that the wind speed in the UK has been dropping off for the last four years or is there likely to be a software solution? I understand that my new 6KW inverter has the latest 7 phase curve in its software which should be more efficient but even on very windy days it is often generationg just a few hundred watts and also sometimes disconnects and appears to be unable to reconnect due to the very high voltages.

The annoying thing is that our all-electric house uses about 10000KWH per year and we should be generating pretty much all our own requirements.

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geoff
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Proven's sales pitch (or marketing budget) is your problem.
I have asked Proven, and my installer to put me in touch with ANYONE who has generated the amount of electricity that they were told they would.
We were told 43,000kWh per annum for a 15kW and in reality it would have been more like maximum 17,000 (if they hadn't been shut down due to all the faults).

Please send me an email (click on my name for contact details) and I will add you to the list of unhappy customers.

I completely understand your frustration.

Jules is correct. The last 2 years have been very poor. About 70% of the usual wind speed. It is not known if this is a temporary drop or a more long term serious problem. Wind strength does work in cycles though so I would not panic just yet. I know this does not explain your very low production though. From information read on this forum I would have a chat with Proven,
Gusty.

Programming a wind inverter, presumably its MPPT power curve, is a bit of a black art; certainly it seem to be much tricker than solar PV MPPT.

So that might indeed have a bearing.

Rgds

Damon

Unfortunately that is not allowed as it breaks the G83 terms.

Geoff, what model SMA inverter do you have now?

CW - What are you basing this calculation on please?
i.e. should this be blatantly obvious to a wind turbine manufacturer/installer? (in other words, they should not even have told us this in the first instance)

thanks
Dominic.

Some turbines get switched off as part of grid balancing, though this should be getting less and less. That can account for some of lower capacity factor. Also new installations may well have a week or so turned off for an installation check.
If windspeeds were only 70% of normal then that is a much bigger drop in power as it is a cube law.

No ST is talking about wind farms.

Britains wind farms now producing 2229MW at present 12.10pm, thats 5.3% out of a shade under 42GW total.

SteamyTea, Do the large scale wind turbines of the 2-3MW variety have a far more linear power curve than much smaller ones, so the cube law is not as prevalent??

Posted By: DamonHDPS. The cube law is fundamentally the energy *available* in the wind.

What the man says. There is also cut in and cut out windspeed, local wind shadowing and turbulence. Last 3 winters we have down here had more North biased winds as opposed to the very usual South Westerlies, any turbine installed down here that is shaded from a North, North West or North East wind will be down on performance purely because of the wind direction.

Generally large commercial turbines are of a much better design. The manufacturers cannot afford to claim greater output figures (for the turbine, not the wind regime) because the operators would be suing them. Different kettle of fish at the domestic level as generally an individual cannot afford to fight a case in the civil courts (though may be interesting to see if the small claims court have a view on lost income from a faulty product).

Is there any evidence that the new composite blades improve the performance of 6kw Proven turbines?
How much do they cost?

Couple of thoughts. One is that you could put up your own weather station and an anemometer to constantly measure the wind speed. That would tell you what your output should be. Ages ago I am sure I found a website of amateur meteorologists who uploaded their data. If there is one near you you could look at their data.

I looked at wind turbines a while back but my concern was that the guarantee period was significantly less than the payback period introducing significant risk to the proposition.

Check that the WindyBoys are not set up as SunnyBoys, have seen that before, and one set correctly and the other not.

Thanks for these comments. We will have the whole thing serviced when we find a contractor in Yorkshire that does not charge the Earth. It would be a pity to scrap it, but the economics just don't add up, sadly.