'Is global warming happening?' Poll discussion/results

magyar

ZTD wrote: »

Yes, but I was talking more from the "high winds stop generation" aspect, rather than no wind at all. Wind power seem to be in rather a cleft stick - too little wind and it stops working, and too much and it stops working.

But the range is very wide, usually 2 or 3 m/s up to 25 m/s.

ZTD wrote: »

But I would also expect those 9 minutes would be rather demanding of the blades.

It's the gearboxes, rather than the blades (the blades would happily manage several hundred miles an hour I imagine!). I'll get you the answer on gusting.

ZTD wrote: »

Well no - but the difference is thought provoking in itself. The turbines may be rated at X kW, but over an averaged hour you'd only get nX kWh (average) out of them (where n<1), depending on how good the site was. I assume you'd plan for the nX kWh.

All wind farms have a 'capacity factor' which is the 'n' you're describing. The UK average is 29% although newer sites tend to be 30-35% (many existing sites use quite old, less efficient turbines). Offshore is typically 35-40%.

The figure used in capacity planning is the 'P50' which is the amount of energy which will exceeded 50% of the time. This is pretty average over a year.

ZTD wrote: »

You get high pressure in winter too. Leads to clear skies and extreme cold. Which then leads to high demand, and no power lines blowing down to ease the load.

You do, in which case we will have to turn everything on! I reiterate, I'm not suggesting wind displaces capacity, merely it's capable of displacing generation. Your initial point was that conventional stations are inefficient when they run up and down, but this isn't really the case - due to the accuracy of forecasting.

ZTD

magyar wrote: »

It's the gearboxes, rather than the blades

Really? What's the loads on the gearboxes? The only problems I can see for that are if the blades are unbalanced, and that should be easy enough to sort.

magyar wrote: »

(the blades would happily manage several hundred miles an hour I imagine!).

Under static conditions yes, but remember there's the constant shedding of vortices which make the blades vibrate, and the "vibration" caused by any given blade approaching the tower, (causing compression and then moving away from the tower causing low pressure). Along with centripetal force, and blades made out of composites, that looks like a recipe for failure through fatigue if you let them get out of hand.

magyar wrote: »

I'll get you the answer on gusting.

Thanks.

magyar wrote: »

You do, in which case we will have to turn everything on! I reiterate, I'm not suggesting wind displaces capacity, merely it's capable of displacing generation.

But is the EU target not for capacity?

magyar wrote: »

Your initial point was that conventional stations are inefficient when they run up and down, but this isn't really the case - due to the accuracy of forecasting.

It actually wasn't my point - although it is true. But it's not one of the more important considerations.

Power plants are inefficient when allowed to cool down, (because they work best at their "operating temperature") and are inefficient when they are running when they don't need to be. They are financially inefficient when idle. Or in short - any state other than flat-out generating electicity is inefficient. Perfect forecasting can minimise those inefficiencies, but since they originate from the variability of the demand, it can never be eliminated. Wind power doesn't help because it brings it's own variability. That will increase inefficiency - but it's not fatal.

Now a question (from an accounting perspective) would be: If a coal powerstation stands unused, and hence not earning money because of a wind farm - should its general "costs" be attributed to the powerstation - or the wind farm?

magyar

ZTD wrote: »

Really? What's the loads on the gearboxes? The only problems I can see for that are if the blades are unbalanced, and that should be easy enough to sort.

It's to do with the fact that the theoretical power of the turbine is far greater than the rating of the generator.


So this turbine starts generating at ~4m/s and reaches its peak output at about 15m/s and the gearbox controls the speed of the generator. Once it reaches 15m/s the blades pitch to curtail the output to the maximum the generator can handle. You could theoretically have gearbox which allows you to go higher, but in practice it would be too heavy for the tower

ZTD wrote: »

Under static conditions yes, but remember there's the constant shedding of vortices which make the blades vibrate, and the "vibration" caused by any given blade approaching the tower, (causing compression and then moving away from the tower causing low pressure). Along with centripetal force, and blades made out of composites, that looks like a recipe for failure through fatigue if you let them get out of hand.

Not going to argue with that, it was an fairly flippant comment: as I say, it's not the blades that limit them.

ZTD wrote: »

But is the EU target not for capacity?

No, it's generation.

European Union leaders have agreed on a binding target of 20% of EU energy consumption to come from renewable sources by 2020.

ZTD wrote: »

Now a question (from an accounting perspective) would be: If a coal powerstation stands unused, and hence not earning money because of a wind farm - should its general "costs" be attributed to the powerstation - or the wind farm?

It wouldn't be financially inefficient from the perspective of the coal station operator, because if there was no wind and you had to run less efficient power stations, the price would go up.

indigo8

After seeing the Despaches programme a few months ago,it certainly makes you wonder what all the fuss is about. It was claimed that Co2 in the atmosphere was made up of only 0.45% and recorded times in the past if the scientific scare mongers were right when coal output / petrol vehicles / industry / ECT ECT were churning out these polutions the tempreture should have risen over 2/3 decades to alarming proportiones, but in fact the global tempreture went down and there were fears at one point that we were heading for an Ice Age which also didn't materialize.
There is always a Dept looking to cash in either on taxes or penalties which continue to bleed the people of this Country where will it end?

indigo 8.

ZTD

magyar wrote: »

No, it's generation.

I can see all sorts of fun and games in the lies, damned lies and statistics department if there turns out to be a "still" year with not much wind...

magyar wrote: »

It wouldn't be financially inefficient from the perspective of the coal station operator, because if there was no wind and you had to run less efficient power stations, the price would go up.

But on the flip side of the coin, if there was wind, you'd have a coal powerstation sitting there doing nothing.

The reason I was wondering from an accounting point of view is in the case of someone owning "both sides of the coin" as it were. If the use of wind turbines was to decrease the profitability of coal powerstations (assuming the accounting went that way) then that might encourage companies to ditch the coal stations in a rather short-sightedly eerie echo of "the dash for gas". As you've pointed out - a lot of powerstations are up for renewal soon.

The reason why I was wondering at all was in researching various bits, it was pointed out that wind achieves a lot of its apparent profitability by externalising its costs. Backup in case of calm days being one of them.

magyar

ZTD wrote: »

I can see all sorts of fun and games in the lies, damned lies and statistics department if there turns out to be a "still" year with not much wind...

If only! Sadly, it doesn't work like that. The generating companies would just get heavily fined. But you don't get 'still' years, anyway. You just don't.

But on the flip side of the coin, if there was wind, you'd have a coal powerstation sitting there doing nothing.

ZTD wrote: »

The reason I was wondering from an accounting point of view is in the case of someone owning "both sides of the coin" as it were. If the use of wind turbines was to decrease the profitability of coal powerstations (assuming the accounting went that way) then that might encourage companies to ditch the coal stations in a rather short-sightedly eerie echo of "the dash for gas". As you've pointed out - a lot of powerstations are up for renewal soon.

The reason why I was wondering at all was in researching various bits, it was pointed out that wind achieves a lot of its apparent profitability by externalising its costs. Backup in case of calm days being one of them.

I think your last point is fair. Coal probably is going to drop in use, and I think it's got a place even in a renewable world: carbon capture and storage is possible (although very expensive). The profitability or otherwise of wind at the moment is entirely down to one thing: the price of turbines. There are few credible manufacturers and it's a supply-led market, so prices are 'whatever the market will bear'. So it's almost impossible to do a comparison.

By the way, nice to debate with you ZTD; it's good to have a chat with someone and not be called a lentil-knitting tree-hugger for a change. :beer:

Al-boy

Global warming? we are being conditioned to accept that taxes will increase, as we have been for the last 30 years that I know of. If CO2 was the threat then the late 1800's until the 1960's would have caused planetary meltdown. The chimneys in every town in the UK were still spewing out the waste from coal burnig until very recently. growing up in the 60's I have vivid recollection of my home town under a blanket of smog when viewed from the hill road and the vast array of smoke belching stacks peircing the artificialy created horizon.

They now blame the car, excuse being that car numbers have grown 10 fold. Sorry, but the vehicle emmissions have fallen 1000 fold in the last 15 years. They now have advanced electronic control to acheive stochiometric fuel/air ratios. exhaust gas recirculation to eliminate Oxides of nitrogen ((nox) cause of acid rain). And Catyitic convertors to further reduce CO and CO2 level, as everyone who submits a car for MOT will know, if the readings are above a phenominally low level the vehicle will fail the test. you can no longer commit suicide with a hose up the exhaust.

What is actually happening is that farmers are being government subsidised to keep cows, which produce millions of tons of greenhouse gas. the motorist is being forced to pay this subsidy. The answer, to the alleged problem would be get rid of the cows

magyar

Al-Boy, I'm not entering into the debate about whether global warming is man-made or not (I don't think that's going to be won or lost on this thread!) but just a couple of factual points.

Al-boy wrote: »

The chimneys in every town in the UK were still spewing out the waste from coal burnig until very recently. growing up in the 60's I have vivid recollection of my home town under a blanket of smog when viewed from the hill road and the vast array of smoke belching stacks peircing the artificialy created horizon.

Smog is caused by particulates and sulphur dioxides from coal combustion and is nothing to do with the level of CO2, and smoke is basically lumps of carbon. Modern combustion doesn't cause these effects, because of the clean air acts of the 50s and 60s. But burning 'clean coal' (as well as gas and oil) produces CO2. Since our energy consumption levels have increased dramatically, so has the CO2.

Al-boy wrote: »

And Catyitic convertors to further reduce CO and CO2 level, as everyone who submits a car for MOT will know, if the readings are above a phenominally low level the vehicle will fail the test. you can no longer commit suicide with a hose up the exhaust.

Catalytic converters don't reduce CO2 levels, in fact they technically increase it slightly as it ensures that the CO is fully converted to CO2.

ZTD

magyar wrote: »

If only! Sadly, it doesn't work like that. The generating companies would just get heavily fined.

You mean they wouldn't lie? Or collude? Of course they wouldn't... :rolleyes:

I can see wind farms being built near existing powerstations to "efficiently share infrastructure" and of course make it impossible to externally audit exactly how much of the electricity coming from the site is green and how much is brown.

But of course I'm a cynic.

magyar wrote: »

But you don't get 'still' years, anyway. You just don't.

I'm not talking about the whole year being still all over the country - I'm just talking about there being significantly less amounts of wind for a year. I believe it's El Nino that does that, and La Nina increases the winds - at least over the UK/Atlantic.

Indeed we get wet years, dry years, hot years and cold years. And then of course hot&wet, hot&dry etc etc... For wind not to be part of that variability would certain be worth studying. But of course it is part of that.

I actually remember saying to a friend in 1987 "Is it just me, or has this year been really windy?" He of course replied "It's just you." But 10 days later, half the country blew over.

magyar wrote: »

I think your last point is fair. Coal probably is going to drop in use,

It depends on what you mean by that and over what time scale. Gas use is going to drop - both in relative and absolute terms. The ole "Dash from Gas". I think that's pretty obvious. The question being what will replace it. It's a lot easier to replace gas burners with coal burners (I'm discounting oil for obvious reasons), than knock the (relatively new) gas powerstations down and replace them with nuclear.

"Easier" probably being the understatement of the century.

Even that's assuming nuclear goes ahead. I have the feeling its going to take a few people freezing to death before people start to get the hint. So over the short term/medium term I think coal will rise both in relative and absolute terms being mostly driven by gas swaps. After that...it depends on the rise (or otherwise) of nuclear and of changes in demand.

It may very well be coal drops in relative terms, but capacity rises.

magyar wrote: »

and I think it's got a place even in a renewable world: carbon capture and storage is possible (although very expensive).

Well the Mexicans are using CO2 injection (as well as every other method including kitchen-sink injection) to try to maintain production volume on their Cantrell oilfield. Though to no avail. We too have an oilfield that has passed its production peak - so there is an opportunity there.

Of course whether it should be done at all is an entirely different debate.

magyar wrote: »

The profitability or otherwise of wind at the moment is entirely down to one thing: the price of turbines. There are few credible manufacturers and it's a supply-led market, so prices are 'whatever the market will bear'. So it's almost impossible to do a comparison.

That's only at the moment. If it's that profitable, other manufacturers will come into the fray. In a couple of years time they'll all be made in China - just like everything else.

magyar wrote: »

By the way, nice to debate with you ZTD; it's good to have a chat with someone and not be called a lentil-knitting tree-hugger for a change. :beer:

And you too :beer: You've not called me a blind creationist simpleton (in denial) who works for oil companies.

Yet...

ZTD

And I'm shocked (yes it's possible) - no one has added to this...

More grist for the mill...