On the necessity of Wind Measurements

[Poivrier]

Hi to all,

I work for a telecommunication company.  We are contemplating cutting down on fuel consumption at remote sites by installing wind turbines.  We are investigating using micro to small units (anywhere from the 100W Ampair to the approx. 10kW Bergey turbines).  Since our site power requirements are diverse, it would likely be a combination of models within that range.  

I have been struggling to find out a documentation that explains at what output range it starts to make sense to perform wind measurement on site.  Certainly, I do not see this being necessary for a 100 W unit.  On the other side, when is it economically justifiable to invest time and resource in wind measurements? 10 kW, 50 kW or only for wind farms?

Best Regards to all

I am happy to have come across this forum, great place to learn!

Poivrier

[SparWeb]

Time may be the biggest factor.  You can't understand the annual variation of wind at any site unless you've measured the wind there constantly, for at least one year.  Even then, there's enough variation from year to year that one year's data cannot be completely be trusted.  Several years will smooth out the ripples and "anomalies".  How many years are you willing to wait to reduce your fuel use?

But then, it's not always windy.  How many days will your system go without wind before systems use up the battery charge?

All of the autonomous stations that I've seen; ie.: well-heads, pipeline pressure/flow monitoring stations, etc. use a solar panel or two, and in a case below them is a stack of AGM batteries.  No hot electric dump loads, no moving parts, and there is at least a bit of sun every day (unless you're north of 66).

Just checking to see why you need wind power instead of solar (I know, I know, it's a wind-power forum, etc... not singing from the official hymn sheet...)

[Flux]

As Steven said you will need measurements for several years to get a good feel for the wind potential but for small set-ups you can probably manage with local data from wind surveys and airfields combined with a lot of common sense.

If a local airfield has very low wind potential and you are at a worse site then it doesn't make much sense to continue.

If the local areas have a reasonable average wind speed then you are in with a chance. You can easily see if there are local circumstances that will make things fail, trees upwind of the prevailing direction will cause you lots of problems unless you can get at least 30ft above them. Obstructions downwind are not so bad and if the prevailing direction is clear you may be ok.

There are wind maps for most areas and these can be reasonably accurate if your site is typical. If you are very high and exposed you will certainly do better. If it is low or obstructed then you may be well below the predicted figure. Someone with reasonable wind power experience could usually get a very good idea how you will compare with published data.

With small micro turbines it is probably cheaper and more accurate to install a turbine than run a wind survey. Even at the 10kW level you can with care and common sense decide whether it will pay off.

If you are going for a commercial wind farm with huge initial costs then obviously an accurate and long term survey is essential.

Most people ( not all) seem to find it obvious that you don't fit solar panels in the shade but many seem capable of locating turbines in areas where they will work badly or not at all. Just use a lot of common sense.

There will be times with no wind at any site and this may be the most difficult thing to estimate without a survey. That is a big issue if it is your only supply but for energy saving it is less of an issue. You will almost certainly find that you need wind and solar unless it is a really windy site and you can afford an over sized battery bank.

Flux