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Old 03-01-2013, 11:16 AM   #504 (permalink)
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Originally Posted by jamesqf View Post
Then why do you need peaking plants that sit around burning fuel but not producing electricity?
Take a look here
U.K. National Grid status

This is a real time set of gauges that show demand and supply in the UK system.

Because of that when oy read it it will be different, so note the weekly and monthly graphs - note how coal and nuclear stay stable. They are used as baseload because a) they work all the time, and b) its harder to start / stop one quickly as demand changes.

Note the Hydro, Wind etc. Hydro is small in the UK - only in the Scottish highlands and in Wales, but is it regular and reliable. Bio is also minimal but stable at 0.75GW - again like coal and nuclear you can't switch it on and off. We don't have a lot of solar.

So wind - it goes up and down all the time.

Because of the way the grid has been told to behave by Greenpeace, oh sorry, I mean it has to take whatever "renewables" generate, which is sometimes not all that it could - it is what the owners of the fans want to provide and when they want to provide it.

So if you look at CCGT (aka Gas) it has to go up and down to compensate - that is the idling, using fuel, making CO2 "backup" to that oh so reliable, and cheap wind stuff. And if our European friends have some spare we take from them too top up too (ICT).

The bottom line is the UK is an industrial country (still) so we need more baseload - new nuclear, or more gas, or get on with fracking asap - we have potentially a world record deposit in Cumbria. We can afford to do this if we didn't subsidise windmills and solar.

Originally Posted by jamesqf View Post
So you're claiming that your mostly fossil-fueled electric grid is 100% reliable? Sorry, but the facts don't back you up.
Its not 100% no, the overground lines in some places come down and the infrastructure is in dire need of an upgrade - as is Transport, comms - the lot. A whole lot of digging and putting new stuff in.

Originally Posted by jamesqf View Post
Don't you folks have cordless power tools over there?
So I have to know when the power is off to charge them, or just leave then on charge all the time ? Is that efficient ? And when the charge runs out and the power is not back on ?

Originally Posted by jamesqf View Post
What exactly do you think happens now when one of those (statistically rare) events happen? How does the current system smooth out all those peaks & valleys? You have what is called "spinning reserve" on the grid. This is essentially inertia - the rotational inertia of spinning generators (you may or may not have noticed that wind turbines spin), and the electromagnetic equivalent in inductance & capacitance. This supports system frequency & voltage long enough for that gas turbine to come up to speed, or the gates on the hydro dam to be opened a little more.
What happens here is that as demand rises, pumped storage is used to keep the grid up whilst the CCGT begins to generate. Wind is not reliable enough. As our pumped storage is limited (and should be expanded) CCGT is kept more online than it needs to be.

Originally Posted by jamesqf View Post
But note that when we're talking about supplying power to 3rd world areas, where there isn't an existing grid, this simply isn't an issue. Everyone has their own system, and knows (or should know) what they have in reserve, just as you know how much fuel you have in your tank.
Well, see those graphs above - the UK is being told (by the EU) to close 10% of our capacity (coal) due to CO2 allegedly. Oh, we can build new ones with CCS except nobody has that working anywhere yet, because it doesn't work.

That means we will be down to under 5% of spare capacity compared to peak demand.

So maybe I need to buy a generator too. And if we all do then how is that better for CO2, I'm going to run it on Diesel. And no I can't burn wood - clean air act came into force to get rid of those "pea souper" London fogs.

Originally Posted by jamesqf View Post
Actually this is almost trivially simple. You put several plastic jugs of water in the freezer. This serves as thermal mass: if the power is interrupted for more than a few hours, you move the jugs to the refrigerator compartment. Or you might look up the original "icebox" Icebox - Wikipedia, the free encyclopedia that people used before mechanical refrigeration was invented. Ice was harvested from lakes and stored year round.
I might need make use of that

Originally Posted by jamesqf View Post
A more interesting problem is how you support a major intermittent draw, for instance an electric arc furnace used for steel recycling. This is a problem I actually worked on, back when I worked for the local power company. The answer turned out to be "We can't, unless you want to pay for building a couple hundred miles of high voltage transmission line." But that's why you put those such things near reliable electric generation - which as I pointed out earlier, is usually renewable hydro.
That problem seems simple to solve if you have the baseload to supply it, transmission can be solved up to some distances (we use AC over here, I believe that makes transmission less loss-y ?). If you use coal then it can be transported as you say by train - good point, gas can go by train or better by pipeline.

Hydro ? The UK has some limited Hydro (see above) but it is only located in the highlands of Scotland and some in Wales (see pumped storage above). The UK is small so flooding a new area to install a dam is going to be a difficult proposition, if for no other reason than the lack of space to do it and all those areas are "protected" by law.

And as I keep saying, Wind doesn't do it.

Originally Posted by jamesqf View Post
Humm... You live in Britain, and claim that trains can't be made to run on electricity?
Funnily enough though that electricty has to be reliable too or the trains shut down, just like the steelworks. I prefer Diesel electric Hybrids which we had in the 1960s. An electric train brought down 1km of it's overhead cable in South England last week - the network returned to Diesels.

Originally Posted by jamesqf View Post
Methane from your local sewage plant :-)
I'll use my own Methane thank you Its a possibility, I just don't want power bills to rise to subsidise it - if someone does it commercially thats OK, it is also reliable too.

And on a related point, remember all those "skeptics" claiming that CO2 can't cause warming, because in the past the warming always came before the rise in CO2? Well, turns out that might not be the case after all: CO2 Warmed Antarctica In the Past | Climate Change | LiveScience[/QUOTE]

It was a climate scientist, Nir Shaviv who said it depends on the samples and frequency and that it might be tricky to draw any conclusions at all.

Still any new paper is to be welcomed - we all like science

Is the guy who did this one is after some kind of group funding for an expedition or something ?
[I]So long and thanks for all the fish.[/I]