Go Back   EcoModder Forum > Off-Topic > The Lounge
Register Now
 Register Now
 

Closed Thread  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 02-28-2013, 05:24 PM   #501 (permalink)
The PRC.
 
Join Date: Oct 2009
Location: Elsewhere.
Posts: 5,304
Thanks: 285
Thanked 535 Times in 384 Posts
Quote:
Originally Posted by jamesqf View Post
The stations aren't the problem (assuming your probably government-run 3rd world utility can afford to buy fuel for the generating station), it's the grid. If you have sufficient generation on the grid to support demand, all is well*. If demand exceeds generation, then you get brownouts, blackouts, destroyed equipment, &c. See any EE text on powerflow & stability.
Our power generation is 1st world and is private, has been for 20 years - keep up at the back We also invented nuclear power, but the wrong kind but we do know what power is.

Think about "sufficient generation" for a moment, that is the problem.

Quote:
Originally Posted by jamesqf View Post
*Well, all is well until you get a wind or ice storm taking down a lot of lines. (My neighbor's kid works as an electric lineman in the Midwest, and you just wouldn't believe what he makes in a week after a big storm.) Or you maybe have a solar flare blowing out parts of the grid... Then you have the cost of running power lines all over the place - lines made of increasingly-expensive copper, which people will steal even when the lines are energized, lending a double meaning to "hot" merchandise :-)
Most lines in the UK are underground - ever wonder why we dig up the roads so much - guess where the lines went We do have some remote areas supplied by pylon lines but there are plans to move them underground as well.

Quote:
Originally Posted by jamesqf View Post
Now if you, as a person living in a 3rd-world country (or even a rural area of the US or Europe), just happen to want enough power to run lights, charge a cell phone or computer, maybe run a refrigerator or the occasional power tool, a solar or wind system looks like a pretty reliable alternative.
Have you thought this through fully ? What if you want to run your power tool and it is dark and the wind is not blowing, then what ?

Also think about this carefully - you are in charge of the grid - how do you plan for when all those people need their fridge or phone or lights ? And how many ? And what about if they all want Microwaves ? And how the hell do you run a fridge on interrupted power anyway - I mean cheaply.

To manage that you need reliable and "sufficient generation"

Quote:
Originally Posted by jamesqf View Post
You build your steel plant near a hydroelectric dam or nuclear plant, and ship the steel (or aluminum, etc) to where it's needed. Why do you think that most US aluminium production is (or was at one time) located near the Columbia River? And most other production is located where renewable hydroelectic power is plentiful?
You forgot the bit where you transport the ore to the plant, in trucks (which are not hybrids) or trains (which are not hybrids or cannot be built by hybrid machinery) and that transporting the stuff away again is also not on renewables. Thats before we think of the rails, and the track, and the landscaping to make a path and the machinery that does all of that bit.

Quote:
Originally Posted by jamesqf View Post
Sorry, but no. Properly designed peaking plants tend to be gas turbines, which can be brought from cold start to full power in minutes. They're also required for grids that are primarily powered by fossil fuels, since demand fluctuates.
What makes those gas turbines turn ?

__________________
[I]So long and thanks for all the fish.[/I]
 
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 02-28-2013, 07:29 PM   #502 (permalink)
Master EcoModder
 
Join Date: Jun 2008
Location: Earth
Posts: 5,209
Thanks: 225
Thanked 803 Times in 589 Posts
Quote:
Originally Posted by Arragonis View Post
Our power generation is 1st world and is private, has been for 20 years - keep up at the back
Then why do you need peaking plants that sit around burning fuel but not producing electricity?

Quote:
Most lines in the UK are underground - ever wonder why we dig up the roads so much - guess where the lines went
So you're claiming that your mostly fossil-fueled electric grid is 100% reliable? Sorry, but the facts don't back you up.

Quote:
What if you want to run your power tool and it is dark and the wind is not blowing, then what ?
Don't you folks have cordless power tools over there?

Quote:
Also think about this carefully - you are in charge of the grid - how do you plan for when all those people need their fridge or phone or lights ? And how many ? And what about if they all want Microwaves ?
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.

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.

Quote:
And how the hell do you run a fridge on interrupted power anyway - I mean cheaply.
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.

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.

Quote:
You forgot the bit where you transport the ore to the plant, in trucks (which are not hybrids) or trains (which are not hybrids or cannot be built by hybrid machinery) and that transporting the stuff away again is also not on renewables.
Humm... You live in Britain, and claim that trains can't be made to run on electricity?

Quote:
What makes those gas turbines turn ?
Methane from your local sewage plant :-)

--------------------------------------

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

Last edited by jamesqf; 03-01-2013 at 01:37 PM..
 
The Following User Says Thank You to jamesqf For This Useful Post:
Occasionally6 (07-11-2013)
Old 02-28-2013, 08:36 PM   #503 (permalink)
Master EcoModder
 
NeilBlanchard's Avatar
 
Join Date: May 2008
Location: Maynard, MA Eaarth
Posts: 7,539

Mica Blue - '05 Scion xA RS 2.0
Team Toyota
90 day: 42.48 mpg (US)

Forest - '15 Nissan Leaf S
Team Nissan
90 day: 156.46 mpg (US)

Number 7 - '15 VW e-Golf SEL
TEAM VW AUDI Group
90 day: 155.81 mpg (US)
Thanks: 2,883
Thanked 2,570 Times in 1,598 Posts
Methane digesters can use sewage which produces both methane and fixed nitrogen fertilizer. They also can be run on plant or animal farm waste; in Germany they use the corn *stalks* to produce biogas for their peaker plants. It can be produced and stored the same way natural gas can.
__________________
Sincerely, Neil

http://neilblanchard.blogspot.com/
 
Old 03-01-2013, 11:16 AM   #504 (permalink)
The PRC.
 
Join Date: Oct 2009
Location: Elsewhere.
Posts: 5,304
Thanks: 285
Thanked 535 Times in 384 Posts
Quote:
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 uk.gov 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.

Quote:
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.

Quote:
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 ?

Quote:
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.

Quote:
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.

Quote:
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

Quote:
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.

Quote:
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.

Quote:
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]
 
Old 03-01-2013, 11:20 AM   #505 (permalink)
The PRC.
 
Join Date: Oct 2009
Location: Elsewhere.
Posts: 5,304
Thanks: 285
Thanked 535 Times in 384 Posts
Quote:
Originally Posted by NeilBlanchard View Post
Methane digesters can use sewage which produces both methane and fixed nitrogen fertilizer. They also can be run on plant or animal farm waste; in Germany they use the corn *stalks* to produce biogas for their peaker plants. It can be produced and stored the same way natural gas can.
Even us evil skeptics are not against this, anything which increases efficiency is good, just no subsidies.

The largest Tomato grower in the UK uses biomass from older Tomato plants and other waste to produce enough energy and gas to power their hothouses.

They didn't need a bit of my power bill to do it.
__________________
[I]So long and thanks for all the fish.[/I]
 
Old 03-01-2013, 12:39 PM   #506 (permalink)
Not Doug
 
Xist's Avatar
 
Join Date: Jun 2012
Location: Show Low, AZ
Posts: 7,819

Chorizo - '00 Honda Civic HX, baby! :D
90 day: 35.35 mpg (US)

Mid-Life Crisis Fighter - '99 Honda Accord LX
90 day: 37.81 mpg (US)
Thanks: 4,989
Thanked 1,470 Times in 1,113 Posts
Quote:
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 consider bottles to be up to two or three litres and jugs being a gallon or more. I just do not have the room, but when I have my own place, I want a chest freezer!

In the Phoenix area, our small and man-made lakes do not freeze, although I have a picture of a giant frozen puddle on the sidewalk at Arizona State.

 
Old 03-01-2013, 12:49 PM   #507 (permalink)
Not Doug
 
Xist's Avatar
 
Join Date: Jun 2012
Location: Show Low, AZ
Posts: 7,819

Chorizo - '00 Honda Civic HX, baby! :D
90 day: 35.35 mpg (US)

Mid-Life Crisis Fighter - '99 Honda Accord LX
90 day: 37.81 mpg (US)
Thanks: 4,989
Thanked 1,470 Times in 1,113 Posts
Quote:
Originally Posted by Arragonis View Post
The largest Tomato grower in the UK uses biomass from older Tomato plants and other waste to produce enough energy and gas to power their hothouses.

They didn't need a bit of my power bill to do it.
I heard about a dairy that almost met their electrical needs on-site, then they started pumping oxygen into the mess and were actually able to sell electricity.
 
Old 03-01-2013, 01:11 PM   #508 (permalink)
The PRC.
 
Join Date: Oct 2009
Location: Elsewhere.
Posts: 5,304
Thanks: 285
Thanked 535 Times in 384 Posts
Quote:
Originally Posted by Xist View Post
I heard about a dairy that almost met their electrical needs on-site, then they started pumping oxygen into the mess and were actually able to sell electricity.
Think about that being "able to sell electricity" part though.

The grid has to match demand and supply.

Suddenly the farmer comes on and pumps some electricity into the grid.

The grid has to accept it (under our scheme) because it is renewable.

If demand is there it might power my PC (for about 10 seconds), or my kettle (for 0.001 seconds). You can't store this stuff* - it gets used when it gets made or not at all.

But he still gets paid by what he puts in. That money comes from an additional percentage of my power bill. Even if his energy actually doesn't do anything. And even if I don't use it.

Is that efficient ? Is it fair ?

*(There is Tech to store energy and electricity, everything from pumped storage (see postage above - it already uses excess energy and doesn't need any more) and huge batteries, and even heated salt bunkers - most are experimental and definitely not in use in the UK to a large extent).

EDIT - If he used it himself and cut his own usage that would be fine.
__________________
[I]So long and thanks for all the fish.[/I]
 
Old 03-01-2013, 02:25 PM   #509 (permalink)
Master EcoModder
 
Join Date: Jun 2008
Location: Earth
Posts: 5,209
Thanks: 225
Thanked 803 Times in 589 Posts
Quote:
Originally Posted by Arragonis View Post
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...
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.

Quote:
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.
And you could afford to build new nuclear, or invest in energy efficiency.

Quote:
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.
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.

Quote:
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 ?
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.

Quote:
And when the charge runs out and the power is not back on ?
And when you want to use a corded power tool, and the power's out?

Quote:
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 ?).
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.

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.
 
The Following User Says Thank You to jamesqf For This Useful Post:
Occasionally6 (07-11-2013)
Old 03-01-2013, 02:38 PM   #510 (permalink)
Not Doug
 
Xist's Avatar
 
Join Date: Jun 2012
Location: Show Low, AZ
Posts: 7,819

Chorizo - '00 Honda Civic HX, baby! :D
90 day: 35.35 mpg (US)

Mid-Life Crisis Fighter - '99 Honda Accord LX
90 day: 37.81 mpg (US)
Thanks: 4,989
Thanked 1,470 Times in 1,113 Posts
Quote:
Originally Posted by jamesqf View Post
And you could afford to build new nuclear, or invest in energy efficiency.



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.
I only have one experience with one third-world country, but they have a consistent problem with things they like blowing up.

I tell you, bridges are handy!

I wonder if they will ever have power lines.

 
Closed Thread  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com