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Renewable Energy: What happens if your turbine installer is "no more"?

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  1.  
    • CommentAuthorsmudger
    • CommentTimeSep 12th 2011
     
    We purchased a property with a recent turbine installation, so should in effect be under warranty. Performance has been erratic and at times underwhelming, so I collated some data. When I tried to contact the installer for some assistance / interpretation it turns out everyone apart from the MD (and the receptionist...) has been laid off through lack of orders. Not technically in liquidation but not actively trading either.

    Can anyone suggest who we can turn to now, to try to improve performance/identify any faults/setting issues, and down the line when we need to look at maintenance and repairs? Based in the SW.
    •  
      CommentAuthorSteamyTea
    • CommentTimeSep 13th 2011
     
    All depends on the turbine make, there are companies down here that will service just about any turbine. The more worrying thing is the poor performance. Is it a siting, inverter, mechanical issue, or a combination?
    Where in the SW are you, it covers a very large area?
    • CommentAuthorsmudger
    • CommentTimeSep 13th 2011
     
    North Devon. Could be all 3 issues without technical and knowledgeable input. It doesn't always run when its windy, but does sometimes when I go up and reboot it. Even when it is running it will stop, then start again say 1 hr later. Its a 6kw but the most we have had until last few days was 17kw in a day. 24hrs up to last night we did get 30kw, but generally it seems to be only ever generating 1-2kwh at most when it is running. We are at 1000ft on a mast and can see Fullabrook to the west. We are just off the ridge so not 100% optimum but think we should be achieving more than we are.

    The company said at one point that there were issues with Western Power grid in that they keep the voltage too high which prevents renewables inputting to the grid as the voltage would increase above their limits. I mentioned this to a WP chap and he wasn't convinced. Said WP should have been notified but they are finding that too many renewables are being connected without that happening (metering is a different dept/company, so doesn't mean everything has been authorised?)

    We did have one big power trip, but hasn't repeated itself. When I have opened up the control panel, there has never been any alarms or anything amiss, just isn't going round. It hasn't used a lot of electricity trying to start either.

    thx for help/advice.
    •  
      CommentAuthorJSHarris
    • CommentTimeSep 13th 2011 edited
     
    To be honest, 1 to 2kW from a 6kW wind turbine seems to be pretty much what's to be expected, given the cube law relationship between wind speed and power, but it all depends on what wind speed the turbine is rated for and what it's actually seeing where it's sited.

    Because of that cube law relationship, small reductions in wind speed at the turbine will give large power reductions, something that's true of all wind turbine (or water turbine) installations, and the reason why getting an accurate survey of wind speeds to be expected at the turbine site is a good idea before going ahead with an installation.

    It sounds as if you're in a potentially good spot, but local flow conditions can make a big difference to performance.

    What is the wind speed for the 6kW rating? If, for example, it is rated for 6kW at 20mph wind speed, then at 10mph wind speed you might expect the turbine to be able to deliver only around 750 watts, just from the cube law effect of power with wind speed.
    • CommentAuthorsmudger
    • CommentTimeSep 13th 2011
     
    Pulled out the manual:

    Rated power is 4kw
    rated power wind speed 11m/s (=25mph/40kmh)
    max power is 6Kw
    reference annual energy - 6.7kw at ave annual windspeed of 5m/s.

    there is a graph (performance curve) indicates:
    zero power output at 4m/s.
    250w at 5m/s
    750w at 6m/s
    1500w at 7m/s
    2250w at 8m/s
    3250w at 9m/s, then pretty much straight line to
    6000 at 11/12m/s

    JS is probably right.

    Another graph correlates windspeed to annual energy production:
    at 4m/s - c4000kwh
    at 5ms - c 6000kwh
    at 6m/s - 10000kwh
    at 7/8m/s - c 12500kwh
    • CommentAuthorsmudger
    • CommentTimeSep 13th 2011
     
    and the MCS Cert says estimated annual generation is 8200kw. This equates to an average of 22kw/day. Two days ago, (our windiest day yet?) we only managed 30kw in a day.
    •  
      CommentAuthorDamonHD
    • CommentTimeSep 13th 2011
     
    Please don't mix kW and kWh; (energy) generation per day and per year as above will be in kWh.

    kW in this case is the (power) output at any one given moment.

    Rgds

    Damon
    •  
      CommentAuthorSteamyTea
    • CommentTimeSep 13th 2011
     
    Don't think there is any harm in mention which turbine you have. Have you checked the windspeeds at your location. What direction is the wind coming from when the turbine is not working?
    •  
      CommentAuthorJSHarris
    • CommentTimeSep 13th 2011
     
    Looking around your rough area, I found some limited wind speed data that suggests that the July/August average was around 10mph, with a maximum of 30 to 35mph. Based on this average wind speed, you should be getting around 750 watts average from the turbine over the past couple of months, which equates to around 18kWh per day.

    The MCS certificate will probably be quoting an annual daily average power, so in the windier months (usually around the autumn and spring equinoxes) you may well see well over 22kWh per day.

    I'd say that your system looks as if it might well be working to spec, based on the very limited data I can get hold of for wind speeds in your area.
    • CommentAuthorsmudger
    • CommentTimeSep 13th 2011
     
    I pulled out some meter readings:
    We have generated 1374kwh over approx a 15week period which equates to 13kwh/day. I thought that was low, but maybe not. What threw me was the fact that we were away for 3 weeks in July/August and when we returned, nothing had been generated at all (the meter reading was unchanged to the decimal). Maybe the situation is its fine when its generating, but there is a question why it seems to stall/ not start sometimes even if wind conditions seem fine. There doesn't seem to be a pattern on wind direction and its operation.

    JSH - could you let me know where you obtained your wind speed data?

    Any suggestions for companies to approach re maintenance/ servicing if original company doesn't come back on line? Turbine is a VWE Field3.

    Thanks for the feedback / opinion/advice. We'll see where we are after a years installation and a first winter.
    • CommentAuthorwindy lamb
    • CommentTimeSep 13th 2011
     
    Seems like it's doing quite well (for a vertical axis machine).:bigsmile:
    •  
      CommentAuthorJSHarris
    • CommentTimeSep 13th 2011
     
    Indeed, it is doing well; I hadn't realised it was a VAWT, that goes some way to explain the slight underperformance.

    Isn't this the model that was on one of the Grand Designs shows and which massively underperformed?

    BTW, the wind speed data was only monthly average and maximum speeds recorded at Ashford, Devon, the nearest data set I could find and probably not very relevant to your site.
    • CommentAuthorsmudger
    • CommentTimeSep 13th 2011
     
    Phew. Nope not mine, that one on GD was a Skyrota.
    •  
      CommentAuthorSteamyTea
    • CommentTimeSep 13th 2011
     
    Bit of a pain to convert your Post Code to OS references but this is about as good as we have for finding windspeeds.
    http://www.decc.gov.uk/en/windspeed/default.aspx

    My default location of 50N 5W has a mean of 7.7 m/s at 45 m, 7.2 m/s at 25 m, and 6.4 m/s at 10 m.
    On its own this tell you nothing other than the mean windspeed, you also need to know the distribution for your area.

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