Severn barrage

[martinr]

http://news.bbc.co.uk/1/hi/scotland/glasgow_and_west/4951236.stm

now if 140 windmills can generate enough for 200000 homes.....

Scottish Power said its £300m Whitelee project .... will generate 322 megawatts of electricity - enough to power nearly every house in Glasgow. But that is peak output. It wont generate 322 megawatts continuously. So it will only generate enough to power nearly every house in Glasgow some of the time. Trouble is, Glasgow wants elec all of the time so will need traditional power stations on permanent standby to generate the shortfall

Are you sure that was a peak & not an average figure?

http://www.scottishrenewables.com/newsitem.asp?id=106
"Europe's largest windfarm with capacity to generate 322MW of electricity"

http://www.scottishrenewables.com/facts.asp
"Over the course of a year, a typical wind farm will generate about 30 per cent of its theoretical maximum, but this rises to over 50 per cent in very windy sites in the North of Scotland. "

Last time I looked, Glasgow was not in the North of Scotland. So the £300m Whitelee project will only generate about 30 per cent of its theoretical maximum. Incidentally, scottishrenewables are in favour of the project, not in opposition to it

 

[Roger W]

[quote="nickwilliams
Probably more relevant to this particular forum is the potential for the increase in the use of coal for power generation, which I would have said is pretty much a certainty. At the moment, something like 2500 tons of Peak District limestone is used every day at Drax alone for flue gas de-sulphurisation. If the amount of coal burned at power stations around the country goes up then the amount of limestone needed for FGD will also increase, and that means more of cavers' favourite landscapes being quarried away to provide it. How long before the country's energy demands means that quarries which we thought were dead for ever (Fairy Cave? Eldon Hill?) get opened up again?

Nick.[/quote]

And that is a worrying thought!

 

[Duncan]

At the moment, something like 2500 tons of Peak District limestone is used every day at Drax alone for flue gas de-sulphurisation.

A quick search reveals quite a density range for limestone, but 2500kg/m3 seems fairly typical and makes for nice round numbers:

At 2.5 tonnes per cubic metre, 2500 tons (or tonnes, they're only slightly different, and Nick was only giving an approx figure anyway) is 1000 m3. That's a cube of limestone ten metres on a side every day.

 

[tubby two]

And that is a worrying thought!

Yes, i'd never comsidered that aspect before.

This isn't quite the level of experience you were looking for nick, but i remember doing some interesting calculations on wind energy (in a-level physics), and one of the other problems was the land area required to generate the power, the turbines only being effective with 'clean' air, i.e. no turbulence caused by other turbines close by. It came to a huge amount, i think nearly 1/4 the area of the british isles!

The other aspect is the mismatch in demand/generation time, with the wind rarely blowing best at times of peak demand. Hence some form of power storage, such as the pump-storage facility in llanberis, is required, or possibly a tidal esturary based system?

Then again, if you go on the principles of physics you can prove most things, including that the majority of the worlds power needs can be met by nuclear energy, the waste problem being solved by dumping it at sea- it would dissolve out to an intensity far less than background energy from the planet, its just finding a way to spread it out thats a problem (well, there might be a few others too...).


Now for the usual silly point-

That's a cube of limestone ten metres on a side every day.

- cant we use this to make some awesome caves/mines to play in ;o).

tt.

 

[emgee]

[quote="nickwilliams
Probably more relevant to this particular forum is the potential for the increase in the use of coal for power generation, which I would have said is pretty much a certainty. At the moment, something like 2500 tons of Peak District limestone is used every day at Drax alone for flue gas de-sulphurisation. If the amount of coal burned at power stations around the country goes up then the amount of limestone needed for FGD will also increase, and that means more of cavers' favourite landscapes being quarried away to provide it. How long before the country's energy demands means that quarries which we thought were dead for ever (Fairy Cave? Eldon Hill?) get opened up again?

Nick.

And that is a worrying thought! [/quote]

Well I'd be very surprised if they re-opened Eldon Hill Quarry but then I find it hard to believe it was ever allowed in the first place (all that digging for one tight muddy passage with some nice pretties at the end). But can we get this 2500 tons a day in perspective. Anyone any idea what the total amount of limestone quarried everyday is? I have the horrible feeling that Drax may not be significant compared to the amount consumed as a result of say one TV "gardening" programme on the joys of a garden covered in bits of rock and that's before we get onto the big users. Does anyone know a figure though?

 

[nickwilliams]

Does anyone know a figure though?

UK consumption of limestone in 2004:

Constructional uses: 59.6 mt (million tonnes)
Cement making: 9.4 mt
Agricultural uses: 0.9 mt
Industrial uses: 6 mt

Source: BGS/ODPM (www.mineralsuk.com/britmin/mpflimestone.pdf)

At 2500 t/day, Drax uses a shade under a million tonnes a year.

Nick

 

[Peter Burgess]

Another impact of the Drax DeSox plant is that the bi-product, gypsum, is used in plasterboard manufacture, and has significantly cut back the demand for gypsum from the mines in Sussex, Cumbria, and Nottinghamshire.

I am told that you can tell where your plasterboard came from by its colour.

Pink - Cumbria or Nottinghamshire
Grey - Sussex
White - Drax.

 

[emgee]

Does anyone know a figure though?

UK consumption of limestone in 2004:

Constructional uses: 59.6 mt (million tonnes)
Cement making: 9.4 mt
Agricultural uses: 0.9 mt
Industrial uses: 6 mt

Source: BGS/ODPM (www.mineralsuk.com/britmin/mpflimestone.pdf)

At 2500 t/day, Drax uses a shade under a million tonnes a year.

Nick

Thank you. I'm impressed.

 

[Roger W]

[quote="nickwilliams

UK consumption of limestone in 2004:

Constructional uses: 59.6 mt (million tonnes)
Cement making: 9.4 mt
Agricultural uses: 0.9 mt
Industrial uses: 6 mt

Nick[/quote]

Awesome! :shock:

That makes a total of 75.9 million tonnes per year.

Taking Duncan's figure of 2.5 tonnes per cubic metre, that equates to something like 30 million cubic metres - yes, 30,000,000 cubic metres.

That's a hole one kilometre each way by 30 metres - say 100 feet - deep!

Imagine that where your favourite 1 km square on the ordnance survey map used to be...

I'm a lousy mathematician - can someone please check my figures?

 

[emgee]

[quote="nickwilliams

UK consumption of limestone in 2004:

Constructional uses: 59.6 mt (million tonnes)
Cement making: 9.4 mt
Agricultural uses: 0.9 mt
Industrial uses: 6 mt

Nick

Awesome! :shock:

That makes a total of 75.9 million tonnes per year.

Taking Duncan's figure of 2.5 tonnes per cubic metre, that equates to something like 30 million cubic metres - yes, 30,000,000 cubic metres.

That's a hole one kilometre each way by 30 metres - say 100 feet - deep!

Imagine that where your favourite 1 km square on the ordnance survey map used to be...

I'm a lousy mathematician - can someone please check my figures?[/quote]

Very approximately that's about the size of Eldon Hill quarry.

 

[Roger W]

And if I've done my sums correctly, we are digging out a hole that big somewhere every year!

:shock:

 

[cap n chris]

.... and if you zoom out from Google Earth you'll quickly see that it should be possible to continue extracting huge quantities of stone for tens of thousands of years without any major problems for as long as there is fuel to power the vehicles to move it.

 

[andymorgan]

And if I've done my sums correctly, we are digging out a hole that big somewhere every year!

:shock:

If you look at East Mendip, then that figure sounds quite believable.

 

[cap n chris]

Which is better:

One large quarry (and cheap stone) or

Hundreds of small quarries (and expensive stone)?

 

[tubby two]

For who, quarry workforce (local?), stone consumers or cavers?

As a caver i'd say lots of little ones. Might uncover more caves then go bust!
Maybe.

tt.

 

[Peter Burgess]

So let's get this right - if we burn coal to make electricity, we put x amount of CO2 into the air. If we want the fumes to be clean, we dig up loads of limestone and transport it to the power station using y amount of fuel in the process. We then turn it into a slurry using z amount more power (more emissions) and then process the resulting waste product into gypsum using a bit more power. So what is the true carbon footprint of a clean coal-fired power station? It is sometimes pointed out how nuclear power isn't so carbon neutral in that energy is used to mine, refine and enrich the uranium fuel. Coal-burning also has its own hidden extras. Just an observation - I'm not trying to make a point here, except, perhaps that it is often a good idea to take a wide view on matters to get the better picture.

 

[Dep]

Not sure that I saw the same programme about a Severn barrage but an idea tha I have come across recently is not a dam/sluice which would indeed have a severe impact on the estuary ecosystem but a series of turbines set in the main channel - essential wind-turbines in the water.
These have no effect on water level, navigation, minimal and highly localised effects on wildlife and can generate a significant amount of power, although not as much as damming the Severn as per the original idea put out decades ago.

Synchronisation between tides and peak-consumption times is not a problem, surplus power can be stored simply by pumping water uhill into reservoirs as they do at Dinorwic (sp?) in Wales.

As for humans destroying the Earth...
I'm not so sure in the longer term...
What we really mean is destroying it for ourselves, life on this planet is virtually indestructable short of reducing the surface to a magma lake.
The day of our years are three-score and ten, etc etc, - we see things as a snap-shot of time and so like to believe in a status quo that does not really exist.
Look at the rocks you cave within and understand the long periods of time that the strata represent - and then consider how humans with their barely 10,000 years and only two centuries of industrialisation would show up in that...
Even if we were to nuke ourselves into oblivion life would recover (without us) and within a few millenia there would be little to see of us except to very sharp-eyed cockroach archaeologists.

 

[cap n chris]

Dep's right of course.

Planet Earth has nothing to fear from us since we're not going to be here long.

 

[paul]

Dep's right of course.

Planet Earth has nothing to fear from us since we're not going to be here long.

A bit like some fleas on a dog arguing over the mess they're making...

 

[whitelackington]

If they build this dam thing, will they have to suck all the mud up from the up-dam side to create more volume.
If they do, that's alot of mud to skirt away!