DOMESTIC WIND TURBINES

willowfarm

wow what a lot of tecci stuff, we have a fortis 5.8kw system installed. had a lots of problems in the start were on out third turbine and second mast, however after lots of swearing,we now have asystem which works very well and produces a fair bit of power this system has only been up and running since april this year but so far on avarage we have produced 1kw per hour when the turbine is running, when the esb send us a statment saying how much we have produced and how much money we have made or not made we will post here a let you all know anyone who wants to chat to me about this feel free to contact

Merch

I reached post 37 before I feel I had to post, there is a lot of good info and detail and overall, I have to agree with Knipex.
Domestic windturbines simply are not capable of developing the necessary power, due mostly to the disturbances in the wind (velocity and turbulence) and due to the max size of turbine practical or allowed.

The problem I still find which i feel i am in opposition with people is that to benefit from selling back to the grid requires inverters and the associated costs of installation,purchase and possibly ongoing maintenance. So I think that unless you were in a really remote location where electricity is not available then it would be cheaper to use any power generated to dump into a heat sink to offset your water heating costs?? as the added cost of supplying back to the grid means it takes even longer to payback.

IMO small turbines are an absolute no no, I'd agree with large or even supper large turbines with blades that spin at a lower speed but develop more power as a consequence of their swept area.

Really we do need some form of incentive to spread the load on the current grid across the day and night so incentives should be made by providers to encourage end users to spread their demand across the 24hrs of a day. They can there run their plants efficiently across the full 24hrs and not be required to have a large variance in the capacity required for day and night.
Unless a really suitable site exists, small scale generation is only useful if a grid connection is not possible or so expensive (distance or location) that it can be justified as it cannot compete with the efficiency of large scale power generation.

knipex wrote: »

I think you will find that I under stand turbines quite well.

Power is measured in KW
Energy is measured in KW hours. or Kw\h

A continuous power draw of 1Kw for one hour is 1Kw hour.

The instantaneous power usage of a Kettle varies depending on brand from 1.5kw to 3Kw. The vast majority of those currently sold are around 3Kw. So an electric kettle will draw 3kw but assumign its only on for 5 minutes will only use 0.25 units (or Kw hours) of electricity.

The difference between power an energy is key to any discussion of any kind on electricity.

An modern electric shower will use approx 9kw
A toaster about 3kw
A microwave about 1.5Kw
Fridge freezer 2 to 3Kw (under load but these are intermittent draws)
A tumble drier about 2 to 3Kw.

(the limit of 3Kw is because this is the max load that can be connected to a standard 13 amp plug.)

To demand on a modern house can vary from a couple of hundred watts to 17Kw at any time.

A 3Kw turbine is capable of generating an output of 3Kw under ideal conditions. So if you have a kettle on then you are maxing out the capacity of the turbine.


A 3Kw turbine will under ideal conditions be capable of theoretically generating 26,280 units in a year.

Unfortunately conditions are not ideal all the time to wind turbines are subjected to what is known as a load factor. This is a calculated percentage of how much electricity they will actually generate compared to their installed capacity and is expressed as a percentage.

This load factor is dependant on location.

For a commercial 3MW wind turbine in Ireland load factors vary from 20% to 35% with the majority being between 25% and 30%.

For a domestic wind turbine load factors a much lower (due to their lower height and the smaller blades meaning there is a smaller window of wind conditions in which they can operate)

I have seen figures vary from 17% to as low as 8%



All my figures are based on your post which I quoted in my reply



Again I am afraid you are mistaken.

Firstly look at it in its simplest form.

The ESB sells you electricity at a cost of 9 cent including all costs associated with transmission etc.

Yet it buys electricity from you at 19cent and then has the cost associated with transmission etc.

Where do you think that extra 10 cent comes from ? Out of fresh air ?

It comes from ESB revenues which means everyone's ESB bill.

Now in a more detailed level.

Domestic wind turbines (even large ones) will generate 3kw, when the wind is blowing at the correct speed. This is completely intermittent and unpredictable. As a result Eirgrid who have to ensure that demand is met cannot include this wind output when calculating the demand for the day. Similarly Oil, gas and coal station (with the exception of OCGT plants) are not designed to vary output. They can be forced to do so but this takes time and vastly reduces their efficiency so they burn more fuel and generate more C02 per MW generated.

The net result is the the supply side cannot vary output to match the variable output of domestic wind turbines.

So in short domestic wind turbines will have no effect on the amount of fuel used or C02 produced.

Or as I put it in my original post domestic wind turbines are a mugs game.




Sorry if I didn't make myself clear.

Bearing in mind my post above.

in short

3MW turbine 24 hours a day 365 days a year = 26280 Kw Hours

Using 30% load factor that's 7884 Kw Hours. x 19 cent = €1,497

Using 15% load factor (which is a high estimate and unlikely to be reached in the majority of locations and certainly not in an urban location) 3,942 Kw hours x 19 cents = €748

Assuming a cost of 14k as quoted by Bladespin then

14,000 / 1497 = 9.35 years

14,000 / 748 = 18.71 years.

Not including maintenance, or any additional costs associated with installation etc.

I hope this clarifies things ?

I agree with what you have said, except the 9 cent, which I'm not sure

knipex wrote: »

Domestic wind-turbines are a mugs game.

Unforunately this is true, people just aren't aware of the components of the formula to calculate power are, to me the wind velocity and area component rule out small scale in most forms, unless they start virtually giving turbines away for almost nothing.

muffler wrote: »

I haven't moderated any of your posts nor have I took issue with the apparent "facts" that you have put forward as you are more than welcome to debate and discuss matters here till the cows come home.

However I dont want to see people who use a particular product and dont subscribe to your opinion being referred to as "mugs"

The choice is entirely yours as to whether you find this forum an acceptable place to post in or not.

Something I'm glad of as I prefer to see the unedited version, Knipex has provided accurate technical information, I have to say i also agree with bladespin on some things but grid ties/invertors cost money, so I'm more in favour of knipex

bladespin wrote: »

I understood all your post, I'm questioning your credibility.


Every unit of electricity has both an economic and carbon cost, therefore every unit generated from something with a much lower carbon cost has to be saving money both as cash and as Carbon levies saved.


Of course the wind is variable that's why the trade system works well, you buy and sell based on your need. Or you could just buy an outback inverter and a big block of batteries.



Expensive maintenance, these are domestic turbines, it's not rocket science to maintain them yourself.


I really don't know where you're getting your information from but it's way off the mark, I've never been busier shipping inverters all over the world, Germany has exploded thanks to new incentives, so has Spain and the UK, there's muted talk here too, if anything our tarrif will increase to match those countries.


To you maybe but to many they're a sound investment.

I think thats a bit unfair, and I dont like to say, you have if you look at impartially which I am trying to do have a vested interest (not an attack) but are those invertors for small scale turbines? what location are they used in, that would make all the difference as their are so many locations where it would be viable to feed into the grid, but also overall what is the percentage of invertors being sold in total compared to the amount of installations??

bladespin

Merch wrote: »

I think thats a bit unfair, and I dont like to say, you have if you look at impartially which I am trying to do have a vested interest (not an attack) but are those invertors for small scale turbines? what location are they used in, that would make all the difference as their are so many locations where it would be viable to feed into the grid, but also overall what is the percentage of invertors being sold in total compared to the amount of installations??

Inverters are up to 6kw (the majority) and all are for small scale domestic use. The inverters are bought by installers and turbine owners from all sorts of places from the ideally suited for turbines to the not quite so ideal.

I don't really understand the rest of your question, could you clarify?

Merch

I mean turbines the invertors are suited for may well be located in areas very suitable for wind power generation, the capacity factor may be greater, the wind velocity may be consistent and higher but the area of small turbines still limits its power generating ability, and if turbines are used in areas that are less suitable such as semi urban or other areas where turbulence is created then the cost/efficiency of turbines power generating ability doesnt outweigh the cost to produce/install/maintain it.

also
There are many millions of electrical installations (indivdual residences), if you are even selling thousands of invertors, that is a tiny dent in the electrical demand and a tiny amount of the power produced.

Small scale wind power cant recoup the cost fewer significantl larger turbine installations can.

I'll have to check it up but for exact figures but if you double the diameter the potential power generated is significantly increased (4 times)
bigger turbine means greater height and not in a semi/sub urban environment means higher wind speeds, as velocity is a cubed function, doubling the wind speed increases potential power generated by 8 times
so small turbines cant compete with larger ones, ie about 32 small turbines in unsuitable areas would not amount to even 1 large turbine in a suitable area

how much are these invertors? how much to install in ireland?

quentingargan

Merch wrote: »

I think that unless you were in a really remote location where electricity is not available then it would be cheaper to use any power generated to dump into a heat sink to offset your water heating costs?? as the added cost of supplying back to the grid means it takes even longer to payback.

IMO small turbines are an absolute no no, I'd agree with large or even supper large turbines with blades that spin at a lower speed but develop more power as a consequence of their swept area.

Contrary to popular belief, you can't really hook a turbine directly to a heater - you need to harvest power from the blades in a more dynamic manner. The ratio between voltage and available power is exponential. So either way, you need a power tracking device such as an inverter to harvest the power from a turbine.

I would agree with much of what you say - it is obviously cheaper to build a 2 megawatt turbine on a mountain, than it is to build a thousand 2kw ones. But you have to rold out a grid to districute the power from mega turbines.

The main reason to incentivise small turbines is to encourage diversity of power sources, and to create local supplies which need no grid.

However, it is also worth supporting a fledgling industry in Ireland producing such turbines. These can then find a market in overseas areas for off-grid phone masts, remote villages, and a myriad other uses. We are never going to beat Denmark and Germany at building mega turbines, but we may manage to have Ireland develop successful industries in the micro-wind market, and if that means paying 19c per Kw Hr for the power from these machines, it might be a low price to pay for dabbling in a new industry during its formative years.

Oh - and 6kw inverters sell for about €1,900 plus VAT. If you were to build the electronics to control a heat dump load, it would probably cost about €400 for a production version to handle 2kw. But you would also need a DC load, DC cabling and other modifications for a PWM based heater.

Samich

it's time for local councils to build a large turbine to be used for town use for everyone, people in the town pay an annual charge. Rather than building lots of domestic turbines

BryanF

Samich wrote: »

it's time for local councils to build a large turbine to be used for town use for everyone, people in the town pay an annual charge. Rather than building lots of domestic turbines

Mods appoligies for digressing from the OP topic but throughout the thread the poor effeciency of domestic turbines and a lack of understanding of what can actually be generated exists....
Samich, i don't think the council will be doing much:) but heres the thing:

Are we in agreement that for the most part (unless were on an island or really remote) that from an efficiency and cost perspective that group schemes are where our money would be better spent?

also, do domestic producers just hold up the gird connections for larger more efficient producers? and rather than suggest the 'self-sufficent' route should we pool finances and set up group schemes?

there seem to some enlightened posters here. so: what does a six kw unit cost, lets say for a simplicity, 10g all in. so if there were 100 people wiling to give ten g to a group scheme, thats a mill to go to the banks with as a deposit (say 15% in the current climate) to develop a reasonable goup scheme (say 6 million pot) a generating X MW's (someone else can guess that) at what 20 times the efficiency ?

how many would opt for this over domestic install given the option?

chris85

I would also be interest in some maintenance cost figures on various turbines.

quentingargan

chris85 wrote: »

I would also be interest in some maintenance cost figures on various turbines.

Good question. I have seen turbines that produce €1K worth of power a year, requiring a €500 annual maintenance schedule.

The simpler the turbine, the less often it should require maintenance. Turbines with complex furling arrangements will tend to need more maintenance, so to my mind, that sort of complexity can only be justified on larger turbines - not on 2.5kw ones.

chris85

quentingargan wrote: »

Good question. I have seen turbines that produce €1K worth of power a year, requiring a €500 annual maintenance schedule.

The simpler the turbine, the less often it should require maintenance. Turbines with complex furling arrangements will tend to need more maintenance, so to my mind, that sort of complexity can only be justified on larger turbines - not on 2.5kw ones.

The simplier the better absolutely. No point in having a money pit of a maintenance schedule and gaining nothing decent out of the process. I would imagine some people have invested in a small domestic turbine without researching the maintenance end or the sales man neglecting to tell them and then find their payback period drastically extended due to this cost.