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Nanny

Joined: 17 Feb 2005
Posts: 4520
Location: carms in wales

Posted: Mon Mar 21, 05 5:55 pm Post subject: wind turbine

glad to hear about windsave as we live on a windy site and that could be useful to us and so much chaper than the more well known brand as they say

as i understood it and in very much layman's terms, you use the wind power first and the electricty board as a top up sort of thing so you only pay the electricty people what you use instead of claiming it back?

or have i got it the wrong way round...

sean
Downsizer Moderator

Joined: 28 Oct 2004
Posts: 42219
Location: North Devon

Posted: Mon Mar 21, 05 6:10 pm Post subject:
The windsave one feeds leccie back into your ringmain after the meter. You don't sell any back to the grid, it just cuts the amount you draw. Is my understanding.

Nanny

Joined: 17 Feb 2005
Posts: 4520
Location: carms in wales

Posted: Mon Mar 21, 05 6:26 pm Post subject: wind turbine
i will certainly bow to your greater knowledge as i havenever understood electricity probably because i can't see it...................i can see the results but don't really iunderstand why

judyofthewoods

Joined: 29 Jan 2005
Posts: 804
Location: Pembrokeshire

Posted: Mon Mar 21, 05 7:45 pm Post subject:

I had a look at the website, but could not realy determine how it works, but my guess is that you do not plug it into the mains, but that you can plug mains devices into the unit, although it does not mention storage. If it is not a mains intertie unit it is probably an inverter with a shunt regulator which diverts the excess power to a dump load (a resistive load). Without storage that would mean you can only take the maximum current available at the time its generated, and any time you don't use the power, its wasted. The inverter would have to be sized for the largest loads you use, and that means additional for surge in stating up motors. There seems to be no mention on what capacity the inverter is, and when it sais 'syncronous' with mains, it may just be the voltage and number of cylces, but not necessarily sine wave power, which means that some electronic goods may not work properly, or may even be damaged, or you get humm.
Grid intertie systems don't simply plug into a socket. First you have to have an agreement with the electricity company and comply with very strict criteria, one being that the inverter must produce grid quality power, i.e. pure sine wave. Those inverters, especially the bigger ones that can handle the power output from that wind turbine at peak, would be very expensive. The way it works with your incoming and outgoing power is a meter which runs one way when your power need is greater at any one time than your own generator supplies, and when you use less than the generator produces, the meter runs in reverse, only much slower, you only get a fraction of the price per unit than what you pay them. Its highly unlikely you'll be making money, or even saving much, renewable energy is not cheap compared to mains per unit. It only becomes cheaper when you live so far removed from the grid that the cost of a new supply would be more expensive, in which case you won't be grid tied anyway. Environmental benifit is another matter of course, but with any form of power, the first priority has got to be reduce need. From what I understand, the power that is fed into the grid is used locally by your neighbours (which is why it has to be of grid quality), as 250V won't travel far. Still, it means less dependance on the grid. However, the powerstation is still going to be running their turbines at the normal rate, its doubtful they would reduce output by one KW because you may be pumping some back in, not until a lot of people did it.

Last edited by judyofthewoods on Mon Mar 21, 05 7:49 pm; edited 1 time in total

dougal

Joined: 15 Jan 2005
Posts: 7184
Location: South Kent

Posted: Mon Mar 21, 05 7:45 pm Post subject:

sean wrote:

You don't sell any back to the grid, it just cuts the amount you draw.

As far as I can tell, surplus energy is dumped as heat from the "plug & play" control box... with big vent openings.

I have two concerns -
- the typical generation amount is likely to be quite small. Power is proportional to the *cube* of windspeed. 1000 watts @ 12m/sec suggests only 125w at their stated UK average of 6m/sec. And the available wind energy will be less, the lower or more sheltered the site.
- Planning is said not to be a problem by Windsave's website, being supposedly within "Permitted Development". But for a domestic installation that means it must not extend beyond the existing roof height (which surely means the turbine would be sheltered?) And for "Agricultural" development, it must be "reasonably necessary for the agricultural business - which is hardly self evident.

Guest

Posted: Mon Mar 21, 05 8:50 pm Post subject:

I still dont think that I get it

I know that people say that battery systems are complicated but why are they so much trouble can they not be combined with solar energy and with total commitment to your own system are you not more conscious of what you use and learn to understand with the seasons and weather conditions if your going to be tight or have surplus.When feeding it back into the grid its not reducing output.

but I still dont understand it

dougal

Joined: 15 Jan 2005
Posts: 7184
Location: South Kent

Posted: Mon Mar 21, 05 9:02 pm Post subject:

Anonymous wrote:

Have a look at Judy's website, follow the energy related links, and if you *still* don't get it - register!

(Batteries don't actually store much energy compared to conventional household usage...)

dougal

Joined: 15 Jan 2005
Posts: 7184
Location: South Kent

Posted: Mon Mar 21, 05 9:37 pm Post subject:

I'm a bit duboius about Windsave's claim of a 5 year payback. Simplistically thats over �200/year saving claimed. Call it �4/week. At 5p/unit (24hr inc E7, approx) thats around 80 units usefully generated. But that's about half the 170 units capability of the kit in constant 12m/sec wind! As per my previous post (windspeed cubed proportionality) I'd expect no more than 1/4 of the 'nominal' output - and would it be occurring at a time when it could be used?
So either they are comparing against very expensive electricity, or they are highly optomistic about the output...

From their website's "News" page it looks like they have someone giving a presentation this Thursday in Newbury. Anyone going to turn up?

Nanny

Joined: 17 Feb 2005
Posts: 4520
Location: carms in wales

Posted: Tue Mar 22, 05 8:12 am Post subject: wind turbine

well judy i read all that about 3 different times and frankly it's all greek to me

i think that i will have to wait and see what develops with the company in the near future and see if it means anything more

what i will want to know is

1: how much will it cost to install for the normal household
2: how much money will it save me on the quarterly bill

i know it says just short of a grand on the website but how much will it really cost is what i would want to know

sean
Downsizer Moderator

Joined: 28 Oct 2004
Posts: 42219
Location: North Devon

Posted: Tue Mar 22, 05 8:28 am Post subject:
On the payback thing, their website suggests that the turbine will qualify for Renewable Obligations Certificates, I assume that they're including the value of these.

dougal

Joined: 15 Jan 2005
Posts: 7184
Location: South Kent

Posted: Tue Mar 22, 05 10:44 am Post subject:

sean wrote:

On the payback thing, their website suggests that the turbine will qualify for Renewable Obligations Certificates, I assume that they're including the value of these.

I'd like to know how ROC's work.
Their website ("Savings") says "Currently an annual ROC credit is worth approx �60 per megawatt." They are selling a 1 kilowatt system. On that basis the maths doesn't sound too good...

tahir

Joined: 28 Oct 2004
Posts: 45668
Location: Essex

Posted: Tue Mar 22, 05 10:46 am Post subject:
I've asked similar questions at the AECB (Association of Environmentally Conscious Buliders) and nobody there's been able to enlighten me either.

dougal

Joined: 15 Jan 2005
Posts: 7184
Location: South Kent

Posted: Tue Mar 22, 05 10:59 am Post subject: Re: wind turbine

Nanny wrote:

what i will want to know is

1: how much will it cost to install for the normal household

That depends!
On how you have it mounted, how high and how far from the house. Its just the cost of cable and the mechanical errection. I suspect they may be hoping to bolt it onto the house, but this cannot give all-round exposure to get efficient harvesting of unobstructed wind. That would be cheap to fit but not very effective. Good only for bragging rights.

Nanny wrote:

2: how much money will it save me on the quarterly bill

That depends!
On how windy your site is, (and how that wind is distributed), how exposed/sheltered the installation is, what you currently pay for electricity, how much electricity you use *constantly*, what the weather's like, whether the wind is blowing when you are using no power at all...
Its very hard to say.

Nanny

Joined: 17 Feb 2005
Posts: 4520
Location: carms in wales

Posted: Wed Mar 23, 05 8:01 am Post subject: wind turbines

all very good points sean and how will they answer them without installation ..i don't know as i don't really understand it all

i want to be more energy efficient but equally i don't want to be taken for a mug....................

we are on a very windy site - one of the highest points round here and although some of the wind is fouled, most of it cuts straight up the garden and against the side of the house so i would imagine that we could have a turbine on the side of the building but i don't know for sure of course.................we must be in a fairly good area for it as there are big plans for a proper wind farm within 4 miles of here subject to all the normal complaints and planning stuff that goes with th really huge turbines...........

i think we are on to a wait and see and read and inwardly digest period of time to see what other people have to say before we commit our hard earned shekels

tahir

Joined: 28 Oct 2004
Posts: 45668
Location: Essex

Posted: Wed Mar 23, 05 11:42 am Post subject:
There's also debate as to whether they can recoup the embodied energy within the expected lifespan of 10 years.

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