TNP's Xmas pressy - better late than never

[geoff]

Yesterdays announcement

[The Natural Philosopher]

sadly that is rather old news, and its all been reversed now.

[brass monkey]

Ahhhh, so it's suddenly viable.

[The Natural Philosopher]

No, the government sat on Davey and told him to recant.

He was in danger of being sacked for telling the truth.

[Windmill]

Many have discovered that telling the truth is the one unforgiveable crime. It is therefore left to small boys to comment on the emperor's apparel.

[Andy Champ]

Comment in today's paper (not that one) that they seem to be wearing out rather faster than they were supposed to, and that this is reducing their output.

Original reference:

AKA

Andy

[tony sayer]

The results show that after allowing for variations in wind speed and site characteristics the average load factor of wind farms declines substantially as they get older, probably due to wear and tear. By 10 years of age the contribution of an average UK wind farm to meeting electricity demand has declined by a third.

This decline in performance means that it is rarely economic to operate wind farms for more than 12 to 15 years. After this period they must be replaced with new machines, a finding that has profound consequences for investors and government alike.

"Probably due to wear and tear"?.

Seems rather vague, what's to wear and tear to affect the output significantly?..

Bearings, generator slip rings, what?...

[The Natural Philosopher]

Professor Hughes is a well known and very respected critic of renewable energy. Unreliability is also one of the reasons why wind farms fail to reach theoretical capacity factors. Half the time half the windmills are shut down awaiting a service.

Making them more reliable involves extra cost and more energy in the manufacturing.

A bad idea whose time came and went hundreds of years ago.

mainlink worked for me.

[The Natural Philosopher]

Ah. You misunderstand. A generator that is down for maintenance ten percent of the time or breaks down at periods of high wind and high generation capacity has a lower AVERAGE output than a new one that is available when the wind is.

Largely bearings and gearboxes. (you don't get much output easily from an alternator doing 60 RPM).

The basic problem is a cantilevered bearing that is holding a massive propellor that is subject to massive flexing and torque variation as the wind gusts and as the blades pass through areas of ground turbulence. That massively stresses bearings. In addition if the shaft is hard coupled to the gearbox, that transmits the stress to that: newer designs are experimenting with flexible coupling to take the side loads and torque shocks off the gearbox but its still a bad thing really.

They did experiment with non gearbox designs but its hard to actually get the power out of them..

Then throw in things like salt spray and bronzesteel surfaces (typical of many bearings) and you have a perfect recipe for electrochemical corrosion, especially in the presence of strong magnetic fields..and guess what there is a a big generator - strong magnetic fields.

Ceramic bearings have been tried, but they take up a lot of power end get hotter, and are more expensive..and take more energy to make.

Finishing off on the mechanical side, squashed bugs general filth and ice can all throw the blades out of balance. So you need electrical blade heating and helicopters to pressure wash the blades..all of which cots money and takes energy..I don't know if there are things like regular oil changes which will of course take oil..and more cost and energy - to replace as well.

Then you need inverters to upconvert the power. Those are big - 2MW peak outputs may have to be catered for. And if you seal that lot against the wind and salt spray, its gonna get HOT. Not good. Then there are te control electronics and the head slew and blade pitch adjusters. More electronics, more bearings, more mechanicals. Any and all of which can and do fail. Sometimes with devastating results.

All; of which is stick up a pole in the wind and rain, not in a nice warm cosy sheltered turbine hall where a mechanic can get to it simply easily and quickly and perform routine maintenance.

Which is why the average MTBF is not years or even months. Its days. Yes folks, on average a turbine will need some non routine maintenance every

50 days or so. That may not stop it working, but if left, it will. Which is why after about 6 months of operation its not uncommon to see a third of the turbines in a given farm not working at any given time...

[dennis]

The air molecules.

[tim.....]

As is the "must be replaced".

I would have thought (I have no real idea) that about 95% of the costs of installing a windmill is in the cost of the structure and the blades.

It's only the turbine that going to wear out and need replacing.

[charles]

and not knowing about real costs, I'd have put that as the most expensive bit. As as for getting up there ....

>

[John Williamson]

What's the expected service life of the composites they use to make the blades?

[tim.....]

why

it's an off the shelf, standard part

putting up a 300 meter high building is not

agreed

tim

[charles]

I very much doubt if any product of that size is "off the shelf". They will be made to order, and just because it is a standard design doesn't mean it's cheap.

[The Natural Philosopher]

I don't think so. Blades are not expensive. neither is a prefab steel tower. Bearings gearboxes and electronics are.

[Jo Stein]

On 31.12.2012 11:17, tim..... wrote: ...

Here is a source for numbers:

The Institution of Engineers and Shipbuilders in Scotland

These estimates of levelised cost have been produced by Colin Gibson,

China show how to get cheap and clean energy:

[The Natural Philosopher]

Ah the great fraud of levelised costs where massive taxation on carbon and nuclear fuel magically makes windpower look attractive, and totally ignores the fact that since wind must be co-operated with fossil, there are other costs involved in providing wind dispatch.

And the resident Believer trots out all the usual fraudulent sources written by renewable energy shills..

[Tim Watts]

All I know is I am wearing out prematurely...

I am attempting to remedy this by adding lots of liquid lubricant.

Happy new year

or whatever...

:-o

[Huge]