Domestic wind turbines

sequence

Cardew is right and too argumentative at the same time. No wonder He/She has 11,504 posts

Cardew

sequence wrote: »

Cardew is right and too argumentative at the same time. No wonder He/She has 11,504 posts

You are correct on both counts;)

thescouselander

sequence wrote: »

Cardew is right and too argumentative at the same time. No wonder He/She has 11,504 posts

Well I've read quite a few of Cardew's posts and I reckon the fast majority of them make good sense.

choille

I used to live somewhere even more remote tham I do now & was off the grid so had a big Proven turbine & inverter. It was a big job.

I think those tiddly ones are a waste of space as would be putting one on a holiday home. It'll get blown off, damaged, nicked.
You also may need Planning permission.

Why do you want to get one?
Would a diesel generator not be more suitable - okay I know it's not green, but for practical purposes if you're off the grid it would be a better option?

Mankysteve

I would say in this case solar PV is the best option. In this case if you want a green power supply. An 1.4kw Install will cost around £7000 and payback in less than 10 years with the new FIT's scheme coemign out.

[Deleted User]

I can declare an interest in this area. I do not work for a renewable or dedicated wind consultancy company but rather work for one of the UKs largest property consultancy companies. As such, I have spent the past 5 years looking at the areas of sustainability and in particular the relevance or non relevance to our clients on energy saving and renewables.

I advocated some 3 years ago on this very forum that "micro" turbines don't work and will never work - Re WINDSAVE in particular.

I do however keep a watching brief for developments on renewables and as of April this year the resulting Double ROCs for microgeneration (that is sub 50kW rated installations - not just wind, but other technology as well) started to show SOME wind turbines as having a payback that was worth looking at in regards to our clients.

My consultancy to clients gives an unbias view - I am as happy to tell a client not to have wind turbines (or other technology) as I am to say yes, because I am paid regardless. What I have to get right is my recommendation, as our business is built upon this level of professional advice.

The resulting FITs (should they come in at the levels proposed) broaden further the sites/technology that can work financially.

I say financially, because at the end of the day, if the technology proposed doesn't pay for itself, there is little point in installing it. My arguement is that there are probably other things that could be achieved with the money that would result in reduced energy usage and carbon reduction - if the proposed technology will not pay back within minimum period of xx years.

So with the above in mind - I have spent the last 9 months reviewing the small scale wind market. I define small scale as c. 6kW to 250kW anything below this is pretty much micro. In almost all cases (accept the very very best sites, micro wind turbines will not pay back). Small scale turbines in average to good sites, can pay back within 7-10 years and the best sites can pay back in 5 years. If you have a business and can write off capital costs under Capital Allowances (speak to your accountant) then 3-4 years may be achieved, but this is the exception and only the lucky few will ever see this.

In order for a project to be viable I think the IRR should be c. 10%+ in real terms.

In reviewing the small scale wind market the following is worth bearing in mind.

1) Does the turbine you are looking at stack up from a theoretical output point of view.

Many/ to most wind turbine manufacturers publish power curves that are physically impossible to achieve. There is a theoretical limit of 59% of the winds power that can be extracted (BETZ law).

It is amazing how many power curves appear to bend this rule of physics.

2) Can you see actual proof of figures of output from existing installations. The word proof is unfortunate because the company XXXXX have just had to re-adjust their power curve on their 15kW machine because it couldn't achieve 15kW in independent verificaiton testing. At the same time XXXXX, do make a perfectly decent 6kW turbine - although its performance is very dependent on high wind speeds, not the normal UK average.

3) How many and for how long have the turbines been installed.

Plenty of imports and what I call the "double glazing mk2" companies starting to show up with the ensuing FITs coming in.

These companies will sell you a turbine regardless of whether it will work on not and whether you have the wind resource.

4) Check the rated peak output against real wind speeds. Most turbine manufactures pick a peak output that relates to huge wind speeds, ie. 12m/s. The average mean UK wind speed is 5 m/s on a national basis. The power in the wind is a cubic relationship and every 1m per second of wind speeds sees an enourmous potential increase in power generation. However if the wind only occasionally blows above 5 m/s then your generation will be well down on the theoretical output.

That is not to say that there are not good sites around the country. The south west of england, the coastal areas, Wales and Scotland all have potential wind speeds of 6m/s+ at hub heights of 20m plus.

I'm afraid the NOABL data set is not very good for calculating wind speed at low hub heights and tends to give over optimistic wind data.

Try the Carbon Trust wind estimator, which is much more accurate and will give realistic figures.

However as soon as you get into an Urban environment, I would avoid any wind turbine like the plague - it will not peform.

5) HAWTS VS VAWTs or traditional wind turbines versus the ones that look like spirals or cut in half baked bean tins.

VAWTs will never produce the same level of generation as a HAWT. Its a simple matter of maths. Wind power extraction is directly related to swept area of your blades. VAWTs have terrible swept area on a like for like basis with HAWTs. The VAWTs sellers will tell you that their turbines are great in turbulent wind areas (i.e urban) which is fair, they will peform better than a tradiditonal turbine BUT, the wind resource is always rubbish in an urban area to start with, so NO wind turbine is going to produce very much (ref the Warrick wind trials etc).

VAWTs will also say they can be located closer to the ground, because they can deal with the turbulent wind - well again true, but again there will not be sufficient wind either way at these sorts of heights to produce meaningful power.

6) There is a lot more to all of this, but you are probably board of reading it now.

Suffice to say, that if you choose the RIGHT site and the RIGHT turbine wind can work - but the WRONG site with the RIGHT turbine will not work and the WRONG site with the WRONG turbine will be a disaster.

Do your research, do not rush into anything and understand your subject.

Once you get to grips with the basics, you will be able to ascertain if wind will work for you.