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Old 03-01-2013, 03:18 PM   #511 (permalink)
Arragonis
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Quote:
Originally Posted by jamesqf View Post
You completely missed my point, which was NOT that you don't need peaker plants. Of course you do, even in the current system (as your graphs demonstrate). My point is that you don't need to design them in such a way that they idle all the time, burning fuel without generating electricity.

Typical peaker plants are gas turbines, which are basically jet engines. Now does your average airliner sit around idling and burning fuel when it's not flying (or taxiing)? How long does it take to spool up from engine start to takeoff thrust? A few seconds.

Then you figure that wind generation (since that's what you have in the UK) just isn't going to change all that quickly - the wind doesn't suddenly start or stop blowing simultaneously all over Britain, does it? So peaker plants are/should be designed to come on line within that small time.

That also answers your problem with farm/sewage gas generation. Since peaker power is more valuable than baseload, it would pay to store some fraction of the generated gas to use at periods of high demand, rather than supplying baseload.
OK - I misread the idea of turbines being like this - fuel (nuclear / gas / coal / biomass) -> Steam -> turbine -> power

Your idea is fuel (oil or gas really) -> turbines -> power -> grid

So the idea would be that this could smooth the supply from renewables which is unreliable. I need to do more research - is it more efficient to start / stop a gas turbine multiple times vs maintaining nuclear or CCGT as a baseload ? And how do you model it because the wind and solar is so variable ?

Interesting stuff though.

Quote:
Originally Posted by jamesqf View Post
And you could afford to build new nuclear, or invest in energy efficiency.
Power companies here won't build new nuclear because of the lack of clarity on the energy policy - they get paid on what the grid consumes from them.

If uk.gov continue to give "renewables" a priority then if you build nuclear and in the unlikely event renewables do produce a lot of power, you may end up not delivering power to the grid which means no income.

Same for gas at the moment. And nuclear also involves a promise on the costs of removing the station and dealing / storing the waste.

This is where the Climate Change Act comes in because uk.gov has promised a reduced CO2 output, and at the same time has also said we can have growth. So they give renewables a legislative advantage which it doesn't deserve IMHO.

Madness.

Did you know the UK has the largest amount of nuclear waste anywhere ? We kind of promised to "reprocess" it but that didn't work out so we have to store it - for 100,000 years...

Quote:
Originally Posted by jamesqf View Post
Which costs money, no? So the question is whether it's more economical for 3rd world countries, which don't have an existing infrastructure, to build one, or to use distributed power systems.
Depends on the country and the region. In the African cities then central power is better, in the remote areas self generation is probably the only resource available.

Maybe if one source was very efficient maybe that would be better than loads of generators ?

Quote:
Originally Posted by jamesqf View Post
Given competent engineers with a mandate to design for efficiency, this should be no problem. Plug the tool in, it charges when power is available. The "vampire power" used by the current generation of "wall warts" is an artifact of careless design coupled with a 120/220 volt A/C distribution system.
Agreed.

We have a rating for the power usage of domestic items like fridges and cookers - this seems like something to extend here. Perhaps it could also include every device - laptop, smartphone, power tool, plug-in hybrid - anything we plug in.

That would be good.

Quote:
Originally Posted by jamesqf View Post
And when you want to use a corded power tool, and the power's out?
But I don't want the power out at all.

Quote:
Originally Posted by jamesqf View Post
Well, no, it's not simple at all. Remember that inertia thing? If you dump a major load like an arc furnace on to the system, it's analogous to letting out the clutch with your engine at idle. The system effectively stalls: voltage drops (AKA brownout), the local frequency can degrade enough that it gets out of synch with the rest of the grid, you get separation & islanding. Worst case you can get a blackout over the whole system.

So if you want to put your arc furnace out in the desert, quite a long ways from most generation, you obviously have problems.
Well I don't disagree with what you say - you have studied this after all. Here in the UK no place is much more than 500 miles from any other place so our scale is different.

Here if a company wants to build a plant which is going to suddenly consume that level of power then they will also have to agree with a power supplier to provide that level of energy to a schedule. Something like - "Hi I'm Tata steel and I'm about to take (megaenergy) from you in (insert schedule here)" and the energy producer gears up for it. If the consumer (the steel works) misses their power "window" then they pay anyway. This is a commercial thing, it happens now.

This will probably be arranged seperately to the regular grid supply - which is why a lot of steel places and power plants are quite close together - direct supply as you tapped.

Quote:
Originally Posted by jamesqf View Post
The bottom line of all this is that it seems that a lot of people insist on saying "can't", when what they really mean is "that's not the way we've always done it". All the problems are fairly simple, technically, and probably less expensive in the long run than maintain the current system. (And that's without even considering the environmental effects of CO2 & fracking.) You just have a lot of people emotionally & financially invested in business as usual.
With respect that is very simplistic. Like you I would love a much more radical and up to date energy system, but we have a huge "installed base" of households, industry and government using the old system to deal with. Transferring all of that to some new tech. means someone has to pay for it all, and someone has to tell them to do it. And maybe it needs a technology change, which in turn needs more energy, materials and so on.

And at that point we enter the world of politics - government regulation vs the market deciding for itself or costs paid by consumers or by taxpayers.

EDIT - or mandated government charges to consumers which is then taken back by government and spent on something else - which is what happens to 11% of my energy bill each year. I think this is another tax, ~80% of my income goes back the uk.gov each year.

Its a tricky one.

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