Shetland windfarm - Viking Energy

[Guest Anonymous]

du forgot aboot da track up weisdale hill ghosty. it is a mere piddle o a thing yet da erosion aroond it is hellish

[ArabiaTerra]

How much electricity does it take to run a windfarm?

 

No, not a trick question, but the answer is a surprising amount.

Somebody mentioned it to me a while back an I looked it up for a bit more information as I hadn't seen this particular element of the argument on this forum, but it is quite surprising.

 

For ultra-large wind turbines, which the proposed VE scheme would be, there are certain conditions when the turbines themselves require a fair amount of electricity from the grid to operate various functions.

 

For instance, when there are periods of low or no wind, they need to take power from the grid to keep the blades turning slowly. This is because if the whole assembly stops rotating for long periods of time it puts a lot of strain on the bearings and gearing of the hub, as the imbalance of weight distribution can warp and twist the shaft that the blades are mounted on.

On top of that, there are numerous ancillary devices that need power, including feathering pumps, hydraulic pumps, blade pitch control motors and computers, even the red anti collision lights on top need power.

 

However the biggest consumer of power is for the blades themselves when operating in low temperatures, to stop them icing up. Figures quoted show that up to 20% of the turbines' total output can be used simply to heat the blades to stop the formation of ice.

 

This shows that, on top of the construction of the turbines, the roads and infrastructure into them, the transportation of all the assembled parts and the carbon payback time for such a scheme, they really aren't as green as they are made out to be, and certainly don't give us 'free' energy.

 

How much energy does it take to run a diesel power station, or a coal, nuclear, hydro, gas, geothermal station, or even tidal and wave?

 

The fact is that all power generation systems need a small amount of power to run them. The thing about wind power (and wave, tide, hydro and geothermal) is that it doesn't need fuel to generate the power. That's where the "free" part comes from.

[Kevin]

For instance, when there are periods of low or no wind, they need to take power from the grid to keep the blades turning slowly. This is because if the whole assembly stops rotating for long periods of time it puts a lot of strain on the bearings and gearing of the hub, as the imbalance of weight distribution can warp and twist the shaft that the blades are mounted on.

 

 

How much energy does it take to run a diesel power station, or a coal, nuclear, hydro, gas, geothermal station, or even tidal and wave?

 

The fact is that all power generation systems need a small amount of power to run them. The thing about wind power (and wave, tide, hydro and geothermal) is that it doesn't need fuel to generate the power. That's where the "free" part comes from.

 

So where do you 'magic' the power from to run them on a cold,frosty, flat calm winters day?

[paulb]

the interconnector. power goes both ways.

[Grafter]

Not much wind anywhere in Scotland today. What backup power would be available when wind power is absent? Time the Scottish Government had a rethink on their energy policy.

Wind power is very over-rated as a major power source because of its intermittent nature. It cannot be relied on to produce power on demand.

I would be worried indeed if we were reliant on an interconnector for Shetland's backup power. We must have a back up power station here, what about a gas fired one?

[ArabiaTerra]

^^^ There will be a back-up power station built to replace Gremista. I think the plan is to build it at Dales Voe, but it will only be needed if some numpty drags an anchor over the interconnector.

 

As far as there being not much wind in Scotland today, that's when we import power from England or even the Continent as we will be able to do when the European supergrid is up and running.

So where do you 'magic' the power from to run them on a cold,frosty, flat calm winters day?

As paulb said:

the interconnector. power goes both ways.

And anyway, if there's no wind, why would you power them at all?

[paulb]

The idea is to scatter the sites all over the uk. tie them in with hydro wave and tide. the your nuclar power and whatever they invent. lets not get to worried over the nuclar option we have been using french nuclar power for years. aand if one of the reactors went pop we would still be stuffed. anyone been to the hydro mountin in wales multiply them a number of times and there is your storage.

anyone heard of the distict heating scheame that would work on wind heated water. then extreme energy saving and you should make a very big dent in our need for oil/gas and coal.

 

i still think it would make sense to build the new power plant near the new gas plant and buy from them. its got to be cleaner than shipping oil.

[MuckleJoannie]

SSE have plans to erect a wind farm at Gremista. I understand that the power generated will be used to heat water for district heating. The plans will be on view shortly. To my mind this is a much more sensible use of wind power, as the energy created will be stored until it is needed.

 

http://www.shetlandtimes.co.uk/2010/11/12/whats-on-in-shetland-a

 

TUESDAY 23rd to 25th:

Shetland Heat & Power Ltd & SSE Renewables – Public Exhibition re proposed Gremista Wind Farm in Bressay Hall on 23rd, 4-8pm; Tingwall Hall on 24th, 4-8pm; The Lerwick Hotel on 25th, 4-8pm

[Kevin]

So where do you 'magic' the power from to run them on a cold,frosty, flat calm winters day?

And anyway, if there's no wind, why would you power them at all?

 

Read Seaflech's post again - I'm presuming what he writes is true, I've not researched this myself

[Seaflech]

^^^ There will be a back-up power station built to replace Gremista. I think the plan is to build it at Dales Voe, but it will only be needed if some numpty drags an anchor over the interconnector.

 

As far as there being not much wind in Scotland today, that's when we import power from England or even the Continent as we will be able to do when the European supergrid is up and running.

 

AT, you seem to have missed the point of my post, and also totally contradicted yourself.

Firstly:

The thing about wind power (and wave, tide, hydro and geothermal) is that it doesn't need fuel to generate the power. That's where the "free" part comes from.

No, you miss what I am saying completely. Wind energy may be free in the Utopian world that VE propaganda has laid before us, but it sadly isn't that simple. The point I was making (if you had read the post correctly) was that the turbines themselves require a surprisingly large amount of energy FROM THE GRID for various functions, such as keeping them turning in low wind conditions to avoid shaft bending (ouch), and that up to 20% of their own generated power can be used to heat the blades to stop ice forming. Now if the power they need in these conditions comes from the grid, then that is power that is generated from coal, diesel or gas, is it not?

 

 

So where do you 'magic' the power from to run them on a cold,frosty, flat calm winters day?

As paulb said:

the interconnector. power goes both ways.

And anyway, if there's no wind, why would you power them at all?

 

Secondly, When Kevin asked you where this 'magic' energy comes from, that you claim isn't required, you then agree with paulb that the interconnector works both ways, so we can get power back up it!

 

In my opinion anybody who trots out the mantra that wind energy is free energy (with respect to windfarms) is very deluded indeed. It's like the people who say that they have a great mobile phone contract that gives them 20,000 free minutes - for just £45 a month...... You don't get nowt for nowt.

There is an adage that yachting is the most expensive free energy you can have. I would say that windpower is in the same area.

[ArabiaTerra]

No, you miss what I am saying completely. Wind energy may be free in the Utopian world that VE propaganda has laid before us, but it sadly isn't that simple. The point I was making (if you had read the post correctly) was that the turbines themselves require a surprisingly large amount of energy FROM THE GRID for various functions, such as keeping them turning in low wind conditions to avoid shaft bending (ouch), and that up to 20% of their own generated power can be used to heat the blades to stop ice forming. Now if the power they need in these conditions comes from the grid, then that is power that is generated from coal, diesel or gas, is it not?

Firstly, why should it have to be coal oil or gas? Nuclear, hydro, other renewables are all connected to the grid.

 

Secondly, this problem applies to all electricity generation, not just wind. Every power station uses power to run it's control systems and systems for de-icing etc. Look at the Sullom Voe power station. You will see large silver metal boxes on the roof with slatted fronts. These are the air filters for the gas turbines and they also have de-icing apparatus built in.

 

Just stating that wind turbines use up to 20% of their output for something or other and nothing more, implies that this is something unique to wind mills. It isn't. All power generation systems use some of their output for their own purposes, and when they are starting up from cold they will draw this power from the grid, just as the VE turbines will draw power from the grid when they start up.

 

Also, I'd like to see sources for your figures. Saying that they have to be kept turning to avoid shaft bending sounds utterly ridiculous to me. If that were true then you would never see the Burradale turbines stopped. In fact it's not unusual to see one or more of them stopped.

 

In fact, now that I think about it, that shaft bending thing is just complete garbage. There is no reason the shaft would bend, it's a balanced load, so please give me a source for this.

[Seaflech]

No, you miss what I am saying completely. Wind energy may be free in the Utopian world that VE propaganda has laid before us, but it sadly isn't that simple. The point I was making (if you had read the post correctly) was that the turbines themselves require a surprisingly large amount of energy FROM THE GRID for various functions, such as keeping them turning in low wind conditions to avoid shaft bending (ouch), and that up to 20% of their own generated power can be used to heat the blades to stop ice forming. Now if the power they need in these conditions comes from the grid, then that is power that is generated from coal, diesel or gas, is it not?

Firstly, why should it have to be coal oil or gas? Nuclear, hydro, other renewables are all connected to the grid.

 

Secondly, this problem applies to all electricity generation, not just wind. Every power station uses power to run it's control systems and systems for de-icing etc. Look at the Sullom Voe power station. You will see large silver metal boxes on the roof with slatted fronts. These are the air filters for the gas turbines and they also have de-icing apparatus built in.

 

Just stating that wind turbines use up to 20% of their output for something or other and nothing more, implies that this is something unique to wind mills. It isn't. All power generation systems use some of their output for their own purposes, and when they are starting up from cold they will draw this power from the grid, just as the VE turbines will draw power from the grid when they start up.

 

Also, I'd like to see sources for your figures. Saying that they have to be kept turning to avoid shaft bending sounds utterly ridiculous to me. If that were true then you would never see the Burradale turbines stopped. In fact it's not unusual to see one or more of them stopped.

 

In fact, now that I think about it, that shaft bending thing is just complete garbage. There is no reason the shaft would bend, it's a balanced load, so please give me a source for this.

 

The shaft bending 'garbage' is exactly the same principal as leaving a car sitting for ages without turning the wheels - you will get flat spots where it has been sitting. A constantly turning wheel will get no flat spot as its weight is not resting on one spot for a continuous period of time. Same goes for the shafts on wind turbines, and very large ship propellers. Because there is a large weight at the end of a horizontal shaft, gravity acting downwards wants to 'bend' the shaft. As the turbine turns, this weight is evenly distributed between all the bearings in the case, but if it stops turning then almost all the weight is being supported by relatively few bearings at the bottom of the hub, which causes uneven wear on the bearings, which in turn causes warping or bending of the horizontal shaft on which they are mounted.

 

I appreciate exactly what you say about other power sources needing to use power to start up etc, but this quote of up to 20% of a turbine's output being used to keep the blades heated to avoid icing seems like a massive amount, and I only brought it up because I thought it was an interesting point that I hadn't seen mentioned on this forum. Food for thought!

 

My source is a simple google search - there's lots of it out there!

[paulb]

Seaflech is that a constant 20% or does it vary. its not likely that they keep the deicer/heater on all the time. the turbines that we have now must operate under the same set up so do they make a profit. they also turn slowly when its calm. the only time that they should be stopped is when there is work being done. i agree that it would damage them if they stopped for long periods.

[ArabiaTerra]

The shaft bending 'garbage' is exactly the same principal as leaving a car sitting for ages without turning the wheels - you will get flat spots where it has been sitting. A constantly turning wheel will get no flat spot as its weight is not resting on one spot for a continuous period of time. Same goes for the shafts on wind turbines, and very large ship propellers. Because there is a large weight at the end of a horizontal shaft, gravity acting downwards wants to 'bend' the shaft. As the turbine turns, this weight is evenly distributed between all the bearings in the case, but if it stops turning then almost all the weight is being supported by relatively few bearings at the bottom of the hub, which causes uneven wear on the bearings, which in turn causes warping or bending of the horizontal shaft on which they are mounted.

And under what circumstances can you envision the VE windturbines sitting idle for "ages without turning"? Going by the Burradale data, this will be the most efficient windfarm in the world. The longest period any of the turbines will be likely to be idle is a matter of days, and if any one of them was likely to be idle for longer, it could quite easily be cranked around every few days by hand while whatever problem which caused it to be taken out of service was resolved (And if the problem prevented you from turning it by hand, turning it using electrical power wouldn't be possible either).

 

I just don't see this as being a problem which will ever exist in normal operation of the windfarm.

[Seaflech]

Seaflech is that a constant 20% or does it vary. its not likely that they keep the deicer/heater on all the time. the turbines that we have now must operate under the same set up so do they make a profit. they also turn slowly when its calm. the only time that they should be stopped is when there is work being done. i agree that it would damage them if they stopped for long periods.

 

The 20% power required was a maximum value (the range given in most of the quotes on this is 10-20% of total output) for heating the blades, which would only be required in extreme conditions to stop the blades icing up. The problem I can see is that it could be periods of weeks at a time when the blades need anti-icing, like when the ambient temperature is below about +4 deg c with visible moisture. If ice formed on the blades then they would lose their aerodynamic shape and wouldn't turn with any efficiency, if at all. They certainly wouldn't be efficient if they were each using one fifth of their power simply to keep themselves operational.

 

The shaft bending 'garbage' is exactly the same principal as leaving a car sitting for ages without turning the wheels - you will get flat spots where it has been sitting. A constantly turning wheel will get no flat spot as its weight is not resting on one spot for a continuous period of time. Same goes for the shafts on wind turbines, and very large ship propellers. Because there is a large weight at the end of a horizontal shaft, gravity acting downwards wants to 'bend' the shaft. As the turbine turns, this weight is evenly distributed between all the bearings in the case, but if it stops turning then almost all the weight is being supported by relatively few bearings at the bottom of the hub, which causes uneven wear on the bearings, which in turn causes warping or bending of the horizontal shaft on which they are mounted.

And under what circumstances can you envision the VE windturbines sitting idle for "ages without turning"? Going by the Burradale data, this will be the most efficient windfarm in the world. The longest period any of the turbines will be likely to be idle is a matter of days, and if any one of them was likely to be idle for longer, it could quite easily be cranked around every few days by hand while whatever problem which caused it to be taken out of service was resolved (And if the problem prevented you from turning it by hand, turning it using electrical power wouldn't be possible either).

 

I just don't see this as being a problem which will ever exist in normal operation of the windfarm.

 

You obviously don't see it as a problem, I was merely highlighting an aspect of the wind turbine 'efficiency' which I hadn't seen mentioned on this forum, and thought worthy of discussion as the group who are championing this 'wonderful' 'free' (cough cough) energy source have omitted to point out this negative aspect of the operation of wind turbines.

It is, of course, up to you to take it on board or not.