Potential Pitfalls of Domestic Wind Power

Chipboard

I have always been a bit sceptical of wind energy in a domestic situation but the above posts have convinced me that there are alot of snakeoil salesmen operating in this field.

There is loads of 8 m/s (meters per second) and 10 m/s being thrown around and people might think that they live in a windy area but just cos it gets the washing dry doesn't mean it will run a turbine. It may run a turbine but will it produce enough electricity to have a decent payback. Also, the choice of turbine is highly dependent on the mean windspeed and distribution as different models have different power curves. Even if you didn't know specifically about wind energy you could figure this out if you think about it. If you have a particularly windy site you can erect a turbine with great big 12ft wide heavy blades which will turn a high ratio gearbox and a larger generator and produce tonnes of power - this will have a totally differerent power curve to a turbine which would be suitable for a less windy site. I realise that alot of domestic turbines may not have gearboxes but the point still holds - you can't pick your turbine based on sticking your finger in the air.

As well as the mean windspeed you need to know the distribution. A site with a mean windspeed of 10 m/s where the windspeed is 9 m/s 50% of the time and 11 m/s the other 50% of the time would be excellent. A site with a mean windspeed of 10 m/s where the windspeed is 2 m/s 50% of the time and 18 m/s the other 50% of the time (same average) would be useless as it would do nothing at 2 m/s and no domestic turbine would have a powercurve sufficient to maximise output from the 18 m/s. Also it would probably blow off the pole in no time at the max or atleast the bearings would go or it would require increased maintenance.

When erecting large turbines they also measure turbulence intensity as it is another factor which will decide how much maintenance is required - probably not as relevant for domestic turbines as they won't be catching as much wind but would be a factor in extreme wind sites. The landscape, buildings, trees etc can all affect turbulence of wind on the site.

Another factor is planning restrictions - you can't stick these up anywhere. You may not need planning permission but there are rules about the height and placement on the site.

Some posters on here were dismissing the fact that most domestic turbines have a long payback period - this is crazy - the payback period is important. Talking about payback periods of 10+ years is madness - most of these turbines will be sitting in a scrap yard in 10 years time even if they are properly maintained. I would also contend that the payback calculations used, as well as taking no account of wind speed or mean windspeed, also take no account of routine maintenance and replacement parts (even the huge turbines you see on the top of mountains which cost a couple of million each need this).

Sorry for being such a killjoy. I love the idea of wind energy but it has to be done correctly. There's a reason that I keep driving by houses with seized turbines in the garden. These things give wind energy a bad name.

homer911

The guys on the Dragon's Den last night (RTE) were hopeless!

djpbarry

Chipboard, I think your post is probably worthy of it's own thread...

...so here it is.

Chances are that the only domestic wind turbines that will ever outlast their payback time will be homemade diy ones made from scrap!

CJhaughey

Deleted User wrote: »

Chances are that the only domestic wind turbines that will ever outlast their payback time will be homemade diy ones made from scrap!

Thats likely to be because if someone is interested in actually making one and keeping it running they will have the tech knowledge to improve and optimise it for their situation.

quentingargan

It is true that domestic wind turbines don't make commercial sense without subsidy, but the more robust designs will easly outlast their payback time.

The issue is whether or not they should be subsidised. As an emerging technology, I think they should be. It will always be more cost effective to put a 2.5 megawatt turbine on top of a mountain than put a 2.5kw turbine 100 yards from your house. But there are issues such as supporting grids that imply benefits in electricity being, to some extent, generated and used within the locality.

Also, cost effectiveness and payback times for energy are absolutely impossible to predict. Oil is the only major commodity I know of that had a 700 percent increase in price in one year. OK - that has slipped back to 350%.

If energy prices rise by just 10% per annum, then payback times will decrease replidly during the life of the product, whether that is a solar panel, wind turbine or attic insulation - they all make sense in the long run, unless of course, you think that oil is plentiful somewhere in the bowels of the earth, and that the price rises were a conspiracy, rather than due to peak oil.

By the way, the distribution of wind speeds is described by a weighbull curve, and met offices have the data for this curve in various locations around the country. There is very little difference in this curve within Ireland...

Macha

quentingargan wrote: »

It is true that domestic wind turbines don't make commercial sense without subsidy, but the more robust designs will easly outlast their payback time.

The issue is whether or not they should be subsidised. As an emerging technology, I think they should be. It will always be more cost effective to put a 2.5 megawatt turbine on top of a mountain than put a 2.5kw turbine 100 yards from your house. But there are issues such as supporting grids that imply benefits in electricity being, to some extent, generated and used within the locality.

Community wind turbines are an interesting half-way solution between commercial developments and domestic turbines.

quentingargan

taconnol wrote: »

Community wind turbines are an interesting half-way solution between commercial developments and domestic turbines.

Yes, and a shame that ESB has so far refused to allow this sort of development. Even autoproduction where a number of factories might share a large turbine is not allowed as yet. Unless a single consumer is big enough to use all the power produced (e.g. Tesco on another post here) they have to export to the grid, and if that is more than 11kw, you have to join a very large queue of windfarms looking to get connected.

Marcelproust

quentingargan wrote: »

Yes, and a shame that ESB has so far refused to allow this sort of development. Even autoproduction where a number of factories might share a large turbine is not allowed as yet. Unless a single consumer is big enough to use all the power produced (e.g. Tesco on another post here) they have to export to the grid, and if that is more than 11kw, you have to join a very large queue of windfarms looking to get connected.

Wind turbines can be quite dangerous as the blades can fly off and cause damage and the current thinking is that they should be sited away from domestic dwellings and habited areas as much as possible.

As has been said on other threads, wind power is neither reliable or dependable, so to have a number of factories dependant on a wind turbine seems foolish, to be in a situation where your factory was only guaranteed power around 30% of the time.

bladespin

Marcelproust wrote: »

Wind turbines can be quite dangerous as the blades can fly off and cause damage and the current thinking is that they should be sited away from domestic dwellings and habited areas as much as possible.

As has been said on other threads, wind power is neither reliable or dependable, so to have a number of factories dependant on a wind turbine seems foolish, to be in a situation where your factory was only guaranteed power around 30% of the time.

Wow, where did you buy your turbine? I'm not sure who's thinking you refer to as current but most installations I know of are within 100m of the household they supply.

Most turbines sold in Ireland are class 1, they must be able to withstand windspeeds of up to 70m.sec -International elector technical commission

Modern turbines are grid-tied, there's a constant buy/sell relationship with the grid so no user will be dependant on the turbine alone, that would be madness, I'd love to see one site that has constant wind all year long.

The idea is to build up enough credit with the ESB as to cancel out your bill.

I honestly think you've misread the entire concept of micro generation.

OP you're quite right this field does have it's snake oil salespeople, the idea of a payback time being anything less than ten years is pie in the sky bar you're putting the thing on a platform in the atlantic, most good sites will achieve break even after about 13 years, not bad considering a reputable turbine should last about 25 years or more, there are several low maintenance turbines for sale now, none that I know of have gearboxes, 5 year checks and greasing (usually can be done by the owner), downtime would be about 2hrs for that.

The vast majority of windy sites in Ireland have average windspeeds below 7m.sec at 10m high (generator height approx), if a salesman is telling you you have a 10m.sec site I'd be asking for a second opinion TBH.

Planning permission exemption is straightforward, the turbine mustn't be more than 13m high at upper blade tip, it has to be behind the front wall of the dwelling, distance to the boundary has to be 14m and there's a noise limit.

I don't know anyone that invests €15,000 or more in anything without doing their homework first, a windsurvey for your site is a wise investement if you're serious about installing a turbine, this will give a feasability study for the different grads of turbines that you could buy, generally they're done by an indedendant and cost is usually around €250-300.

Marcelproust

bladespin wrote: »

Wow, where did you buy your turbine? I'm not sure who's thinking you refer to as current but most installations I know of are within 100m of the household they supply.

Let’s hope the blades don’t spin off and cause damage. There are many instances of blades becoming detached from the tower, just as also happens with helicopters. Anyone who advises you to site a wind turbine beside or on a domestic dwelling is irresponsible, unless it’s a small and non commercial turbine.

bladespin wrote: »

Modern turbines are grid-tied, there's a constant buy/sell relationship with the grid so no user will be dependant on the turbine alone, that would be madness, I'd love to see one site that has constant wind all year long.

The idea is to build up enough credit with the ESB as to cancel out your bill.

I’m aware of that and assumed most people are. I was, of course, replying to this

quentingargan wrote: »

… autoproduction where a number of factories might share a large turbine is not allowed as yet.

where the member seemed to be suggesting that a single turbine might power a few factories.

bladespin

Marcelproust wrote: »

Let’s hope the blades don’t spin off and cause damage. There are many instances of blades becoming detached from the tower, just as also happens with helicopters. Anyone who advises you to site a wind turbine beside or on a domestic dwelling is irresponsible, unless it’s a small and non commercial turbine.

Reference please, I've never heard of this happening here.

The op is referring to domestic wind turbines not commercial units.

djpbarry

Marcelproust wrote: »

Let’s hope the blades don’t spin off and cause damage. There are many instances of blades becoming detached from the tower, just as also happens with helicopters. Anyone who advises you to site a wind turbine beside or on a domestic dwelling is irresponsible...

If we extend your logic, anyone who flies a helicopter over a residential area is irresponsible, as the aircraft might fall apart mid-flight.