Personal wind turbines

[1ARMEDBANDIT]

Has anyone done a feasibility study on the cost effectiveness and usefulness of a small wind turbine attached to your home?

Rather than have them ruining the countryside we could incorporate them into our homes to run our electrical goods on windy days then revert back to the national grid on calm days. We could half our bills and put less pressure on the big companies.

I remember seeing caravans using them years ago, what became of this idea?

[LazyGun]

I dont think they are considered viable just at the moment. Issues relating to initial cost, planning permission if a high mast is required, urban windspeed, and teething problems with selling microgenerated energy back to the national grid mean its not really a cost effective investment right now - may change though, as capital / fitting / planning costs come down and the reimbursement for power supplied back to the National Grid is sorted out.

http://www.homeheatingguide.co.uk/domestic-win d-energy.html

[heathfield]

Feasibility studies are being carried out all the time. The conclusions are usually that home turbines are just not practical. A recent New Scientist magazine article pointed out that unless you had a turbine big enough to rip the gable wall off your house, it'd be a waste of time. For a new design of home turbine that's reputedly 3 times more efficient than the normal, see here. Note that in favourable conditions it produces a mere 1.2kW. Your standard electric kettle uses 2.0kW, whether the wind's blowing or not.
Turbines for caravans are fine, where you're using it to trickle charge a 12v car battery all the time, then, using the battery for something like a single 12v interior light bulb for a couple of hours at night.

[beso]

The turbine in heathfield's link makes all the usual rubbish claims about performance of vertical axis wind turbines (VAWT). There is nothing new or unique about this design.

No VAWT design has ever been competitive. They are always less efficient than HAWTs because the blades spend more time in drag than they do producing lift. VAWTs always use more materials to build for the same reason. Low solidity VAWTs are generally not self starting meaning they need to be motored to get moving.

Notice the article says "should produce" indicating there are no real performance figures. The photos showing it installed on a building are crude montages of a CAD produced image on a photo of a building (ie fake).

Also notice the designer graduated from the Royal College of Art rather than engineering.

From an engineering point of view the structure looks unlikely to me. The entire turbine is cantilevered from the base meaning it must be exceptionally rigid and have extremely strong bearings. I believe it would blow apart in a strong gale.

I worked for several years in the wind turbine industry. I do know what I am talking about. Urban wind simply turbines don't add up.

[jake-the-peg]

There was a study in the news just last week

http://news.bbc.co.uk/1/hi/sci/tech/8139373.st m

Most locations yileded poor returns but if you live in the Orkneys you're quids in!

According to the report: 'Building mounted turbines monitored in the field trial were primarily installed in urban and suburban locations that were shown to have inadequate wind speeds. The poor location of these turbines has significantly impacted the measured performance of such turbines.'

[rov1200]

I once read that the flapping of a butterflies wings in one continent was enough to create a tornado elsewhere. Imagine what would happen if too many of these wind installations get off the ground.

Come to think of it. The weather has been very blustery lately!

[rov1200]

To give its true name, its called 'Chaos Theory"

"The flapping of a single butterfly's wing today produces a tiny change in the state of the atmosphere. Over a period of time, what the atmosphere actually does diverges from what it would have done. So, in a month's time, a tornado that would have devastated the Indonesian coast doesn't happen. Or maybe one that wasn't going to happen, does."

[jake-the-peg]

Not quite Rov

It would be more accurate to say that the flapping of a butterflies wings coun trigger a tornados in another part of the world.

This is a tenet of "Chaos theory" that some systems (weather is a classic) are very sensitive to initial starting conditions. A slight change in how things start can result in very different outcomes.

So actually whether you put up one yourself could influence where a tornado struck. But you'd never tell whether or not you actually had any effect at all because you can't rerun the weather and even if you could you'd have to reset everything to infinite accuracy to see.

You might then wonder what the point is of this. But you can get usefull information without knowing something with certainty.

For example a weather modelling program might come out with an 80% probability of rain you can't be sure but the information is still useful

[R1Geezer]

right so in order to stop all these hurricanes, tornado's etc we should just swat all the butterflies, they seem to be the dangerous ones here!

[heathfield]

I'm with you, Beso, but FYI the Royal College of Art actually has an Industrial Design Engineering department.

[rov1200]

I frequently go South of Crawley and they have one of those VAWT operating close to the main road. Even in slight wind conditions it is always spinning wildly generating much electricity. It is compact, pleasing to the eye, takes very little space and can be made from plastic materials.

On the reverse side of the coin there is the massive HAWT
sitting mostly idle on the M25 near Watford.

Now that the country including the Lake District and North Sea are splattered with the horrible HAWTs we should have more reflection and research whether VAWT are the answer. It could be an expensive mistake to think otherwise.