Shetland windfarm - Viking Energy

[tabby]

The problem with having a GT taking up the slack from a windfarm is that unless you had a lot of small machines that could come on line in series then you will never have a steady load for the GT which may well be a very inefficient load for that machine i.e. 30% capacity which would then mean that any potential enviromental savings made by the windfarm would be wiped out by the GT having to run at an undesirable load.

[tabby]

On the subject of condensers if you can utilise the heat dumped from the condenser into work then your system efficiency gets much better. As we are going to move the new power station to the landfill at the Greenhead theoretically we could employ the heat dumped from the condenser or if only a GT is used then the heat from the Turbine Exhaust Gas to add energy to the district heating scheme. Cheap heat for the district heating and emproved efficiency for power station thats got to be a win win.

[MuckleJoannie]

The problem with having a GT taking up the slack from a windfarm is that unless you had a lot of small machines that could come on line in series then you will never have a steady load for the GT which may well be a very inefficient load for that machine i.e. 30% capacity which would then mean that any potential enviromental savings made by the windfarm would be wiped out by the GT having to run at an undesirable load.

 

That is why windfarms don't work. Wind generated electricity should be used to pump water for hydro electricity or heat water for district heating. The power generated fluctuates too much to save much energy in convential power stations.

[Urabug]

It is practical to convert wind power into hot water simply by connecting up big “immersion†heaters,

 

These tanks would be something like massive thermos flasks & able to keep the water hot/warm for quite some time allowing for the fluctuation due to the variation in the wind. Water could then be used for district heating schemes. This method is already being used I believe.

 

The other way I could envisage is probably more suited for the conversion of wave & tidal power, but it should be possible to use this energy to compress air which could also be “stored†then could be used to drive generators

[paulb]

don't know about the bigger picture but there are methods to store and use it. running air or ground sourcce heat pumps with it would be intresting to see the energy savings.

 

i know that our lecky bill has now dropped from £240 to around 70 a month. this will go down even more with our new multifuel stove. im hoping it should be down to around 30 a month.

 

if this works for us in a draughty old croft house then it could help a lot of country houses reduce their power demands.

 

i loved phoning the hydro people up aranging a smaller direct debit. it took the guy a while to work out how to do it.

[JGHR]

but it should be possible to use this energy to compress air which could also be “stored†then could be used to drive generators

 

This is an interesting idea, I heard a program on the wireless about a system that the university of Nottingham, i think it was, is developing.They are storing compressed air in underwater bags. Storing underwater gets around the requirement to construct massive pressure vessels. The underwater bags were to be filled by a wind driven compressor designed with the compressor pistons in the blades so no electricity generated directly.

Also I have read about systems which are showing much improved efficencies with cryogenic storage of liquid air/nitrogen, so wind generated energy will likely be able to provide a meaningful contribution in the future.

[ArabiaTerra]

Are you talking about load factor or capacity factor? the two are different. Do you happen to know what the capacity factor for Burradale is over the period that they have had 5 turbines running?

 

What's the difference?

[JGHR]

Are you talking about load factor or capacity factor? the two are different. Do you happen to know what the capacity factor for Burradale is over the period that they have had 5 turbines running?

 

What's the difference?

 

Well, that’s a good question and I’ll do my best to answer it. Load factor is the ratio of average generated power to actual maximum demand over a given period of time. Capacity factor is the ratio of average generated power to theoretical maximum output over a given period of time. Traditionally load factor was a measure of how efficiently a generator was being used(traditional generating plants run must efficiently at, or close to their rated load) and capacity factor is a measure of the generators ability or inability to deliver its full load over the time period. If Burradale has a load factor of 53% that means, to me at least, that its average power output over a given time period is 53% of the maximum power peak they have provided to the grid over the same time period. If Burradale has a capacity factor of 53% that means that its average power output is 53% of its theoretical maximum over the given time period.

 

I am really not sure why load factor would be of much relevance to windfarms, perhaps you can enlighten me?, or why a comparison between capacity factors for different types of generation could possibly be in any way useful, so I am curious why you would present either as a measure of Burradales supposed extraordinary efficiency.

 

So were you talking about load factor or capacity factor and do you happen to know the capacity factor of Burradale since they have had 5 turbines available?

[crofter]

So were you talking about load factor or capacity factor and do you happen to know the capacity factor of Burradale since they have had 5 turbines available?

 

The 53% quoted for burradale is capacity factor, ie 53% of nameplate capacity. But I am not sure if that is for 5 turbines or if it is from stats for the original 3.

 

I am a bit confused confused about reliability theory - although I agree that the probability of breakdowns will increase with an increasing number of components, is there not a trade-off with redundancy? For example, if one turbine at burradale shuts down, they have lost 20%, but if it is only one turbine out of 100, that is just 1%?

[MuckleJoannie]

but it should be possible to use this energy to compress air which could also be “stored†then could be used to drive generators

 

This is an interesting idea, I heard a program on the wireless about a system that the university of Nottingham, i think it was, is developing.They are storing compressed air in underwater bags. Storing underwater gets around the requirement to construct massive pressure vessels. The underwater bags were to be filled by a wind driven compressor designed with the compressor pistons in the blades so no electricity generated directly.

 

There is a series of videos on this project, which is being tested off Orkney.

 

[ArabiaTerra]

So were you talking about load factor or capacity factor and do you happen to know the capacity factor of Burradale since they have had 5 turbines available?

 

The 53% quoted for burradale is capacity factor, ie 53% of nameplate capacity. But I am not sure if that is for 5 turbines or if it is from stats for the original 3.

 

The figures I was given from VE covered the Burradale system over the first 10 years of it's operation. I would quote the e-mail, but I lost it after a computer crash a while ago.

 

I am a bit confused confused about reliability theory - although I agree that the probability of breakdowns will increase with an increasing number of components, is there not a trade-off with redundancy? For example, if one turbine at burradale shuts down, they have lost 20%, but if it is only one turbine out of 100, that is just 1%?

 

Agreed, unless the problem is with the converter station itself, in which case you would lose 100%. But I'm pretty sure any gas turbine station up here exporting South would also need a converter station as the HVDC link is needed to reduce transmission losses over the cable, so this would be irrelevant.

[Urabug]

MuckleJoannie:--- Looks good but I think it will need to be a bit more substantial to stand up to the weather the like of what we may experience in the next couple of days

 

I do see compressed air being used . I would not think that high pressure tanks would be any more danger than say the gas plant at Sullom Voe'

 

Compressed air tanks could be buried say in old disused quarries out of sight & would cause minimal damage if they ruptured.

 

I would think the necessary contraptions required on shore to top up these tanks would be less obtrusive than say 103 wind turbines

 

Allsorts of problems with this methoud ,moisture in the air ect, but I'm sure it could be overcome.

[ArabiaTerra]

MuckleJoannie:--- Looks good but I think it will need to be a bit more substantial to stand up to the weather the like of what we may experience in the next couple of days

 

I do see compressed air being used . I would not think that high pressure tanks would be any more danger than say the gas plant at Sullom Voe'

 

Compressed air tanks could be buried say in old disused quarries out of sight & would cause minimal damage if they ruptured.

 

I would think the necessary contraptions required on shore to top up these tanks would be less obtrusive than say 103 wind turbines

 

Allsorts of problems with this methoud ,moisture in the air ect, but I'm sure it could be overcome.

 

The necessary contraptions onshore to top these things up are the 103 windturbines.

[Urabug]

ArabiaTerra:-- I was thinking more along the line of tidal & wave.

[ArabiaTerra]

ArabiaTerra:-- I was thinking more along the line of tidal & wave.

 

Absolutely, it would be great with any of the new renewable generating systems. But the thing you have to account for is that tidal and wave are still at the prototype stage and even when they do go in to commercial operation they will be significantly more expensive than onshore wind.

 

It all depends on how much extra you're willing to pay for your electricity. Are you willing to see your electric bill more than double in order to keep the windmills off the hills?