Wind turbines

[nightshade]

I think that there must be a better design the current crop of these
windmilling monsters do not seem to be very efficient,old technology?
The more disturbing turbines to my mind are the "must have home turbines"
These seem to be killing bats,I have no figures but have been told many tales

[Strontium]

I suppose if you can persuade a populous to put up with wind turbines why should powerlines be such a problem, in any case, the option of digging up the earth should be enough of a distruption to much more wildlife? (which is best anyway?) Is space necessarily a problem, or even how densely they are spaced, since there are surely turbulence issues that would mean they cannot be so dense. Arent there enough wild open spaces around the coasts that you could sneak in a few without many people noticing. I think the choice you give them is coal power = bad weather, no wildlife, not a nice walk in the country -> solution = wind turbines, good pollutionless energy source, wildlife, and weather. Thing is, if you use less and have local power supply, like solar or water wheel, then chances are you saved the wildlife too.

[kshotton45]

I found this - it's from a report by the Danish Wind Turbine Manufacturers Association, so it may be a bit biased.

Birds and Wind Turbines

Concern has been expressed in newspaper articles and by some bird lovers that wind turbines could be a danger to migrating birds and some even go so far as to call them ‘mincing machines’. Birds often collide with high voltage overhead lines, masts, poles, vehicles and the windows of buildings. Do wind turbines, with their large rotating blades, pose an even greater threat?

Studies of birds and wind turbines
According to the Danish Wind Turbine Manufacturers Association, birds are seldom bothered by wind turbines. Radar studies at a 2- megawatt wind turbine with 60 metre rotor diameter show that birds – by day or night – tend to change their flight route 100-200 metres before the turbine and pass above it at a safe distance.

There are several examples of falcons nesting on cages mounted on wind turbine towers.

The only known site with major bird collision problems is the Altamont Pass in California, which has a great number of lattice-tower type turbines. This has the effect of closing off the pass and bird kills from collisions have been reported.

Some birds get used to wind turbines very quickly; others take longer. The possibilities of siting wind farms next to bird sanctuaries therefore depend on the species in question.

Bird studies from the Yukon show that migratory birds do not collide with wind turbines, but migratory routes of birds will usually be taken into account when siting wind farms.

A study from the Danish Ministry of the Environment says that power lines, including those leading to wind farms, are a much greater danger to birds than the turbines themselves.

Studies from the Netherlands, Denmark and the US show that the total impact on birds from wind farms is negligible compared to the impact from road traffic.
A three-year study, carried out by the National Environmental Research Institute at Kalo, Denmark, concluded that offshore wind turbines have no significant effect on water birds. The overall conclusions from a series of experiments were that the eiders keep a safe distance from the turbines but do not get scared away from their foraging areas by revolving rotors. Also, the eiders showed normal landing behaviour until 100m from the turbines.

“Impact Assessment of an Off-shore Wind Park on Sea Ducks, NERI Technical Report No. 227"

Birds and planning
An environmental impact assessment was carried out before permission was granted for four wind turbines to be erected in an industrial area of Great Yarmouth. A part of that assessment looked at the impact on local bird life.
English Nature guidelines recommend that wind energy projects should be sited at least 800m from areas of high ornithological interest, away from bird migration routes and features attracting high densities of birds.

The study notes that the proposed wind park has been sited 4-6km away from both Breydon Water SPA/SSSI and Great Yarmouth North Denes SPA/SSSI. It is also sited away from migration routes and features attracting high densities of birds. Notable species of birds such as Bewick’s Swan, Ruff, Cormorant, European White-fronted Goose, Wigeon, Golden Plover, Common and Little Terns are identified, together with their use of the area (e.g. for over-wintering, breeding, and roosting). The movement of bird species for breeding, feeding and roosting and also migration routes are taken into account to assess the impact of the wind farm on local bird populations.

The report concluded that the siting of the proposed wind park would not affect the feeding, breeding or migration of the notable bird populations of these two sites.

The combination of evidence that in general birds are not affected by wind turbines, together with care taken over the siting of wind farms near sensitive areas should ensure that birds are not under threat from developments.

[Interpreter]

I don't see any problem in laying underground electricity cables. Many years ago there were machines which dug a trench, laid a cable or pipe and back-filled the trench. The only difficulty being access due to the many buildings which are in the way.

It is unfortunate that British technology lags behind other countries in the production of efficient power stations. Generally powerstations run at 2000 psi pressure. Running them at 3000 psi gives a great increase in output for a lower amount of input. Other countries have managed to produce superheated boilers, but we have not.

Modern powerstations produce very little polution due to the use of efficient precipitators. Cameras monitor the output from chimneys and what people think of as polution coming from these powerstations is actually condensed steam. It must be a bind living downwind of a powerstation as it must always be raining!

I think that the only real way forward is Nuclear fusion. Although having a piece of the sun held in place my magnetic fields looks more science fiction than science fact. The days of coal fired boilers powering hydrogen cooled generators must surely be coming to an end.

[Esmo]

Originally Posted by Tormentil

Hate them.

They're noisy, not cost effective, and will not provide enough power for the UKs needs.

They're a blot on the landscape and a danger to birds.

I shall probably be in trouble again, but I don't believe that these photographs are genuine. Birds of prey can out manouver a windmill blade. Windmills are not pretty, but we need them for our future energy supplies. Wave power and solar power are other ways we can make electricity and we have to do it. It may not look pretty but it's the future. I wonder where Holland would be today if folks had objected to all their windmills , Did they get bird strikes ?
Esmo.

[John D]

Originally Posted by Interpreter

I don't see any problem in laying underground electricity cables. Many years ago there were machines which dug a trench, laid a cable or pipe and back-filled the trench. The only difficulty being access due to the many buildings which are in the way.

It is unfortunate that British technology lags behind other countries in the production of efficient power stations. Generally powerstations run at 2000 psi pressure. Running them at 3000 psi gives a great increase in output for a lower amount of input. Other countries have managed to produce superheated boilers, but we have not.

Modern powerstations produce very little polution due to the use of efficient precipitators. Cameras monitor the output from chimneys and what people think of as polution coming from these powerstations is actually condensed steam. It must be a bind living downwind of a powerstation as it must always be raining!

I think that the only real way forward is Nuclear fusion. Although having a piece of the sun held in place my magnetic fields looks more science fiction than science fact. The days of coal fired boilers powering hydrogen cooled generators must surely be coming to an end.

No problem running cables underground. However what would be the physical size of an underground cable to transmit say 300MW to say 2400MW in the case of a power station over several miles????
Tell me how you would go about, even if it was technically possible, laying an underground cable through the Scottish Highlands or The Lake District ??????? Mechanical cable laying diggers ?????????

Fuel fired power stations in the UK are as efficient in terms of 'thermal efficiency' as any where else in the world. Some countries do have more power from nuclear and because of the operation of such stations they run at a higher 'load factor' and can be said to be more efficient in terms of energy output.
All power stations have 'SUPER-HEATED STEAM' going to the turbines, that in turn drive the alternators, yes even in the UK. Super-heated steam is associated with the high pressure you mention and that pressure becomes critical if optimum conditions have to be met. It is not the case that you just increase pressure from 2000psi to 300psi as you say. Would be very difficult to generate very much at low pressure, would it not? Pressure does become lower as passes through the various stages in the turbine however as energy is extracted from the pressurised steam.
Would be interested to know where there are 'hydrogen cooled' generators in coal fired stations.( by the way it is the TURBINES that requires cooling for optimum operation not the generators/alternators) From my experience in 40 years in the supply industry water was used as the cooling medium. That is why some stations are built on the coast where sea water is abundant or where cooling towers are necessary in power stations built inland, such as in Yorkshire etc)
Sorry for going on a bit but felt some points needed clarification!
John D

[Interpreter]

Originally Posted by John D

Would be interested to know where there are 'hydrogen cooled' generators in coal fired stations.( by the way it is the TURBINES that requires cooling for optimum operation not the generators/alternators) From my experience in 40 years in the supply industry water was used as the cooling medium. That is why some stations are built on the coast where sea water is abundant or where cooling towers are necessary in power stations built inland, such as in Yorkshire etc)
Sorry for going on a bit but felt some points needed clarification!
John D

Dead easy this one. Ratcliffe-on-Soar Power Station. The turbines are cooled by hydrogen gas. Hydrogen has the highest latent heat capacity of any of the gases. Before working on the turbines, the hydrogen is purged by carbon dioxide. It is interesting to see the pipes freezing up as the carbon dioxide travels through them. The CO2 is then purged with air to make it safe for the APOs and engineers to work on them.
What I think you are talking about is the cooling of the water before being returned to the river from whence it came. Water is used to cool this as it passes through the cooling towers. This is a completely different part of the system and water has absolutely nothing to do with the cooling of the generators, if my memory serves me correctly. It is a long time since I was there.
I believe that Germany has superheated boilers. We do not.

[Gill Catton]

Originally Posted by Esmo

I shall probably be in trouble again, but I don't believe that these photographs are genuine. Birds of prey can out manouver a windmill blade. Windmills are not pretty, but we need them for our future energy supplies. Wave power and solar power are other ways we can make electricity and we have to do it. It may not look pretty but it's the future. I wonder where Holland would be today if folks had objected to all their windmills , Did they get bird strikes ?
Esmo.

No unfortunately I suspect these pictures are genuine at least the bottom one, the kite must have flow into a stationary blade because I doubt it would have survived otherwise.

I went to a conference about renewable energy and potential impact on birds and the vultures in the bottom pic are probably one of the case studies that was presented. The problem here came from placing the turbines on top of a ridge that was part of a larger escarpment. Vultures have traditionally glided up on the thermals that naturally form against this escarpment for all time, now this spiral of hot air once it reaches the top and has no wall to curl against pushes rapidly inland and carries the vultures with it ..... straight into the turbines resulting in deaths because the birds don't see them coming.......

Other problems have come for example I think it was in California, eagles and other birds of prey were perching on the tops of the turbines while looking out for prey, they'd spy something on the ground and drop down to catch it but pass straight through the path of the blades whenever that was their line of sight - not recognising them as a threat - as owls don't percieve traffic as a threat (presumably because it doesn't pursue them as a traditional predator might).

I think most birds on days with good visibility are very able to avoid turbines the problems come in when there's poor visibility or low cloud during migration periods which forces large numbers of birds into valleys with turbines....

On balance so long as the lessons above are learnt and so long as turbines aren't placed directly in major migration routes I think the benefits outweigh the costs.

There are lots of exciting potential new energy sources coming up but they are just not yet viable and it could take years before they are....... Its possible that we just don't have years to stand a chance of making things better......

[John D]

Originally Posted by Interpreter

Dead easy this one. Ratcliffe-on-Soar Power Station. The turbines are cooled by hydrogen gas. Hydrogen has the highest latent heat capacity of any of the gases. Before working on the turbines, the hydrogen is purged by carbon dioxide. It is interesting to see the pipes freezing up as the carbon dioxide travels through them. The CO2 is then purged with air to make it safe for the APOs and engineers to work on them.
What I think you are talking about is the cooling of the water before being returned to the river from whence it came. Water is used to cool this as it passes through the cooling towers. This is a completely different part of the system and water has absolutely nothing to do with the cooling of the generators, if my memory serves me correctly. It is a long time since I was there.
I believe that Germany has superheated boilers. We do not.

I did wonder if you meant the cooling of the stator windings and casing etc.
Hydrogen cooling is the norm for cooling within the casing as it is around 7% the density of air and has ten times the thermal capacity of air, thus passing hydrogen rather than air reduces significantly the 'windage losses' and provides greater heat removal.
However the stator windings which are tubular are water cooled.
Must say we are getting away from the original thread!
John D

[Gill Catton]

Originally Posted by John D

It is not practical, efficient or economic to transmit large electrical loads underground. Large electrical loads are transmitted at 'high voltage' on overhead transmission systems.
John D

but it must be from the turbines to whatever contraption then gets the electricity in into the national grid or they would do it this way.