Cumulus Support

My partner periodically drops hints about getting a wind turbine - usually when its very windy! But I'm not convinced it's worth the outlay.

Then I realised I have over a year's wind speed data stored in Cumulus. Surely it would be possible to convert that to some rough figures for the amount of power that would have been generated by a wind turbine over that period, say in Amp hours or watt hours for each day.

I'm not a wind turbine expert but I believe no electricity is generated until the wind speed exceeds a minimum value, nor when the wind speed exceeds a maximum value. So I guess the conversion would need to take these into account.

Is Cumulus able to do this conversion ? If not, has anyone else done this kind of exercise already ? Are there any other existing tools to do this ?

TIA

It would be possible to extract that sort of data (when average speed > min, less than max) from the data if you have it stored in a SQL database, otherwise I think you would have to put it into Excel and do some serious work with it.

You would of course need to obtain the power output for your turbine of choice at a range of wind speeds, then multiply that by the sum of the time the wind spent at each speed range.

tiresias wrote:My partner periodically drops hints about getting a wind turbine - usually when its very windy! But I'm not convinced it's worth the outlay.

TIA

Very windy does not mean your area is good for a turbine. A turbine needs a steady and consistent wind. Your wind run figure can also assist you in deciding if your location is suitable. I obviously do not know your area but I would like to bet that the outlay for a turbine is certainly not worth the money.

Which domestic turbine have you been looking at?

Have you looked at domestic turbines and the payback versus a solar array?

You also need planning permission for a turbine on your roof and in your garden. You also need to have a very large garden to obtain the minimum measurements from fence lines. They are also noisy.

Solar, quiet, no planning (usually) and perform far better in the winter than people think. Shorter payback time.

Thanks, and sorry for the delay in replying. Yes, I'm not convinced it is worth the expense, but I'm hoping to get some actual figures to justify NOT getting the turbine!

We already have solar panels on our narrowboat which provides excellent power except during winter, which is when I often get the hints to buy a wind turbine!

I haven't looked at any specific models yet - but if I could get some usable figures from Cumulus' data then I'll look up the specs for some popular models and see if I can do anything with them.

I'm guessing I would need average wind speed figures, then remove any that were lower than min or higher than max, then average the remaining speed samples out over each day to get an average speed for the whole day (as if the wind had been blowing at that speed for the full 24 hours). Then look up each speed in the turbine specs and convert it to amp-hours for that day.

This sounds as if it will only produce rough figures, but that's OK if the error isn't too great.

Any ideas how I might get the average wind speed figures out of Cumulus, maybe as a CSV file?

Any better ideas of how to process the figures ?

There are average wind speeds in the NOAA-style reports. The annual report will give you the average for each month and an overall average for the year.

If you want individual 10-minute average speeds, they are in the 'monthly' log files, which are in CSV format. See the wiki for the format of the files.

Hi,

tiresias wrote:I'm guessing I would need average wind speed figures, ......

No, you need to calculate the average of the cube of the windspeed! The energy generated by a windmill is proportional to the cube of the windpeed.

That's why the "useful range" of windspeeds is relatively limited. It will depend on the type of windmill, but below perhaps 6 mph (or 9 mph for a vertical axis type) may produce a negligible amount of power. Above perhaps 25 mph and it may need to be "feathered" to prevent damage to itself, or whatever it's attached to.

Boats are of course a location where a (small) windmill does have unique benefits. But that's basically because at sea, windspeeds are higher and there's no "grid" to plug into. I believe the power levels normally would be just to run a radio and navigation lights, etc., rather than serious amounts of energy.

However, Steve may have some better figures because the Orkneys are one location where windmills can be seriously worthwhile.

Cheers, Alan.