Local solar farm
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Originally Posted By: Shannow
As I pointed out previously, you can only have so much unscheduled, non dispatchable generation in a system before stability becomes an issue.
Gas turbines work extremely well as a means to maintain frequency. You keep saying coal and nuclear maintain frequency. That is not true. They act as a base load. You know very well, or should since you work at one, that a coal unit cannot constantly be ramped. There are just too many systems interacting and the huge boiler can't be placed in a constant state of shock. Coal and nuclear have a very complex startup procedure and are not efficient or safe at partial loads. Its just too much stress and too complicated to constantly change the power output of these big complex plants.
So Coal and Nuclear run full tilt all the time and multiple gas turbine peaking plants run on a different governor droop to maintain frequency. These things amount to a jet engine on a skid turning a generator. Combined cycle allows reclamation of exhaust heat to heat a boiler which powers a steam turbine as a secondary process to get much better efficiency.
Now to address other ways of providing frequency control. The biggest is pump storage where you have 2 reservoirs where the top runs thru the gen on peak and the gen is reversed into a motor during off peak to pump from the lower reservoir to upper. The efficiency of this system is much better than batteries.
I worked with a company in Texas that use air pumps to pressurize underground caverns during off peak then generate using the pressure on peak. So there are new technologies emerging everyday to solve the frequency control problem you mention. Batteries would be another. Clean diesel running off biofuels. Heat sinks of different kinds. Flywheel storage.
To fold your arms and proclaim these problems are unsolvable is not the true spirit of engineering.
As I pointed out previously, you can only have so much unscheduled, non dispatchable generation in a system before stability becomes an issue.
Gas turbines work extremely well as a means to maintain frequency. You keep saying coal and nuclear maintain frequency. That is not true. They act as a base load. You know very well, or should since you work at one, that a coal unit cannot constantly be ramped. There are just too many systems interacting and the huge boiler can't be placed in a constant state of shock. Coal and nuclear have a very complex startup procedure and are not efficient or safe at partial loads. Its just too much stress and too complicated to constantly change the power output of these big complex plants.
So Coal and Nuclear run full tilt all the time and multiple gas turbine peaking plants run on a different governor droop to maintain frequency. These things amount to a jet engine on a skid turning a generator. Combined cycle allows reclamation of exhaust heat to heat a boiler which powers a steam turbine as a secondary process to get much better efficiency.
Now to address other ways of providing frequency control. The biggest is pump storage where you have 2 reservoirs where the top runs thru the gen on peak and the gen is reversed into a motor during off peak to pump from the lower reservoir to upper. The efficiency of this system is much better than batteries.
I worked with a company in Texas that use air pumps to pressurize underground caverns during off peak then generate using the pressure on peak. So there are new technologies emerging everyday to solve the frequency control problem you mention. Batteries would be another. Clean diesel running off biofuels. Heat sinks of different kinds. Flywheel storage.
To fold your arms and proclaim these problems are unsolvable is not the true spirit of engineering.
OVERKILL
$100 Site Donor 2021
Originally Posted By: turtlevette
So Coal and Nuclear run full tilt all the time
This is pretty much my understanding of the system as well. Places like Bruce and Darlington up here run full-bore all the time proving the "base" power for the province.
Originally Posted By: turtlevette
and multiple gas turbine peaking plants run on a different governor droop to maintain frequency. These things amount to a jet engine on a skid turning a generator. Combined cycle allows reclamation of exhaust heat to heat a boiler which powers a steam turbine as a secondary process to get much better efficiency.
Now to address other ways of providing frequency control. The biggest is pump storage where you have 2 reservoirs where the top runs thru the gen on peak and the gen is reversed into a motor during off peak to pump from the lower reservoir to upper. The efficiency of this system is much better than batteries.
I worked with a company in Texas that use air pumps to pressurize underground caverns during off peak then generate using the pressure on peak. So there are new technologies emerging everyday to solve the frequency control problem you mention. Batteries would be another. Clean diesel running off biofuels. Heat sinks of different kinds. Flywheel storage.
To fold your arms and proclaim these problems are unsolvable is not the true spirit of engineering.
This is the part where I think we have an issue in Ontario. We are trying to implement all of these inconsistent green power efforts whilst lacking the regulation infrastructure to compensate for their flux. The stalwarts are dams and nuclear for the most part which, as noted, aren't capable of reactive response. This creates what Shannow is talking about, which is instability.
That said, I don't think these are, as you've said, unsolvable problems. You've cited a number of examples of ways of dealing with it. It would seem though that it is common to put the cart before the horse in terms of creating the instability and then trying to deal with it rather than a proper planning process that caters to inconsistent power production first and subsequently avoids the issues
So Coal and Nuclear run full tilt all the time
This is pretty much my understanding of the system as well. Places like Bruce and Darlington up here run full-bore all the time proving the "base" power for the province.
Originally Posted By: turtlevette
and multiple gas turbine peaking plants run on a different governor droop to maintain frequency. These things amount to a jet engine on a skid turning a generator. Combined cycle allows reclamation of exhaust heat to heat a boiler which powers a steam turbine as a secondary process to get much better efficiency.
Now to address other ways of providing frequency control. The biggest is pump storage where you have 2 reservoirs where the top runs thru the gen on peak and the gen is reversed into a motor during off peak to pump from the lower reservoir to upper. The efficiency of this system is much better than batteries.
I worked with a company in Texas that use air pumps to pressurize underground caverns during off peak then generate using the pressure on peak. So there are new technologies emerging everyday to solve the frequency control problem you mention. Batteries would be another. Clean diesel running off biofuels. Heat sinks of different kinds. Flywheel storage.
To fold your arms and proclaim these problems are unsolvable is not the true spirit of engineering.
This is the part where I think we have an issue in Ontario. We are trying to implement all of these inconsistent green power efforts whilst lacking the regulation infrastructure to compensate for their flux. The stalwarts are dams and nuclear for the most part which, as noted, aren't capable of reactive response. This creates what Shannow is talking about, which is instability.
That said, I don't think these are, as you've said, unsolvable problems. You've cited a number of examples of ways of dealing with it. It would seem though that it is common to put the cart before the horse in terms of creating the instability and then trying to deal with it rather than a proper planning process that caters to inconsistent power production first and subsequently avoids the issues
electric vehicles and locomotives can act as generation sources to support frequency.
Heck let's put a generator in every yuppie's stationary cycle.
The other side of this is smart grid. Loads can be shed in the same way that generation can be dispatched. You can put some on special discount rates to shed selected loads on peak.
Voltage reduction is another grid management tool. Lowering voltage reduces connected load by a few percent. You can go in 2% steps. You won't even notice the difference if voltage drops 10%.
Heck let's put a generator in every yuppie's stationary cycle.
The other side of this is smart grid. Loads can be shed in the same way that generation can be dispatched. You can put some on special discount rates to shed selected loads on peak.
Voltage reduction is another grid management tool. Lowering voltage reduces connected load by a few percent. You can go in 2% steps. You won't even notice the difference if voltage drops 10%.
Originally Posted By: SHOZ
You just plug it into the outlet.
Electricity is metered and comes off the transformers as 220V. You can't get that by pluging into a 120V receptacle.
You just plug it into the outlet.
Electricity is metered and comes off the transformers as 220V. You can't get that by pluging into a 120V receptacle.
Originally Posted By: Al
Originally Posted By: SHOZ
You just plug it into the outlet.
Electricity is metered and comes off the transformers as 220V. You can't get that by pluging into a 120V receptacle.
Sure you can. It's 240 not 220. Half of 240 is 120. You have 2 legs of 120. Its all in the firing angle on the inverter. You sure can make power flow in either direction on any voltage level.
Whether the utility will accept it is another matter. But why tell them?
Originally Posted By: SHOZ
You just plug it into the outlet.
Electricity is metered and comes off the transformers as 220V. You can't get that by pluging into a 120V receptacle.
Sure you can. It's 240 not 220. Half of 240 is 120. You have 2 legs of 120. Its all in the firing angle on the inverter. You sure can make power flow in either direction on any voltage level.
Whether the utility will accept it is another matter. But why tell them?
Originally Posted By: turtlevette
That is not true. They act as a base load. You know very well, or should since you work at one, that a coal unit cannot constantly be ramped. There are just too many systems interacting and the huge boiler can't be placed in a constant state of shock. Coal and nuclear have a very complex startup procedure and are not efficient or safe at partial loads. Its just too much stress and too complicated to constantly change the power output of these big complex plants.
OK, now I know you are talking out your fundamental orifice...
Citations please...
Lack of frequency control and Safety will do...because it simply is not true.
I agree with a lot of you other parts...the loss of that compressed air storage company was sad...see my rolling coal thread in another area for novel uses of lignite.
That is not true. They act as a base load. You know very well, or should since you work at one, that a coal unit cannot constantly be ramped. There are just too many systems interacting and the huge boiler can't be placed in a constant state of shock. Coal and nuclear have a very complex startup procedure and are not efficient or safe at partial loads. Its just too much stress and too complicated to constantly change the power output of these big complex plants.
OK, now I know you are talking out your fundamental orifice...
Citations please...
Lack of frequency control and Safety will do...because it simply is not true.
I agree with a lot of you other parts...the loss of that compressed air storage company was sad...see my rolling coal thread in another area for novel uses of lignite.
Originally Posted By: Shannow
OK, now I know you are talking out your fundamental orifice...
Citations please...
Lack of frequency control and Safety will do...because it simply is not true.
It's professional opinion. You don't think maximum efficiencies are close to full output? Most engineers know this.
It's always safer not to trip a reactor you want to bring it down in a controlled manner. More chance of a trip during power ramps.
Talk to your operators if you don't believe me. I suppose you have nuclear experience too.
OK, now I know you are talking out your fundamental orifice...
Citations please...
Lack of frequency control and Safety will do...because it simply is not true.
It's professional opinion. You don't think maximum efficiencies are close to full output? Most engineers know this.
It's always safer not to trip a reactor you want to bring it down in a controlled manner. More chance of a trip during power ramps.
Talk to your operators if you don't believe me. I suppose you have nuclear experience too.
No, I know thermal efficiency...am talking coal...you were too...happy to limit it to that.
Coal
inability to provide Frequency Control.
inability to operate safely at low load.
I'll refresh your post...
Originally Posted By: turtlevette
That is not true. They act as a base load. You know very well, or should since you work at one, that a coal unit cannot constantly be ramped. There are just too many systems interacting and the huge boiler can't be placed in a constant state of shock. Coal and nuclear have a very complex startup procedure and are not efficient or safe at partial loads. Its just too much stress and too complicated to constantly change the power output of these big complex plants.
Coal
inability to provide Frequency Control.
inability to operate safely at low load.
I'll refresh your post...
Originally Posted By: turtlevette
That is not true. They act as a base load. You know very well, or should since you work at one, that a coal unit cannot constantly be ramped. There are just too many systems interacting and the huge boiler can't be placed in a constant state of shock. Coal and nuclear have a very complex startup procedure and are not efficient or safe at partial loads. Its just too much stress and too complicated to constantly change the power output of these big complex plants.
Originally Posted By: Shannow
No, I know thermal efficiency...am talking coal...you were too...happy to limit it to that.
Coal
inability to provide Frequency Control.
inability to operate safely at low load.
Heres' a an IEEE abstract:
Power plants are increasingly located far from demand centers in Japan due to siting difficulties. As a result, these power plants are connected to a weak part of the network where severe contingencies could separate them from the main grid. This is a particular concern for coal-fired thermal power plants because of their larger footprints and environmental impact. Coal-fired thermal power plants, which have a relatively slow frequency response, can account for a majority of generation in an islanded system. In order to establish countermeasures for this problem and to maintain stable operation of the islanded system, the authors have developed models of coal-fired thermal power plants for system studies. This paper describes important findings obtained from analyses using the developed models, such as the necessity of modeling the power plant control system including main steam pressure dynamics which can limit the governor response to bring back frequency.
No, I know thermal efficiency...am talking coal...you were too...happy to limit it to that.
Coal
inability to provide Frequency Control.
inability to operate safely at low load.
Heres' a an IEEE abstract:
Power plants are increasingly located far from demand centers in Japan due to siting difficulties. As a result, these power plants are connected to a weak part of the network where severe contingencies could separate them from the main grid. This is a particular concern for coal-fired thermal power plants because of their larger footprints and environmental impact. Coal-fired thermal power plants, which have a relatively slow frequency response, can account for a majority of generation in an islanded system. In order to establish countermeasures for this problem and to maintain stable operation of the islanded system, the authors have developed models of coal-fired thermal power plants for system studies. This paper describes important findings obtained from analyses using the developed models, such as the necessity of modeling the power plant control system including main steam pressure dynamics which can limit the governor response to bring back frequency.
Turtlevette, you've picked the wrong paper...that's about islanded plants in a grid separation, not normal grid response...islanded wind and solar produce nada.
Two types of response turtlevette.
The first is the governing margin that the Units are operating at. If the frequency drops, the governor opens the throttle valves, and the unit reacts...instantly, giving everything it can...and it's usually required to be about 10% of rated load...instantly. Advanced power plants will have bled steam throttling, or feedwater cut for additional short term capacity...that's 5 second max response. Failure to respond means fines.
a GT on standby will be there 5 minutes later.
Once the initial load is gained, the control system has to increase pressure and firing rate to sustain it...Oz system stability requirements are 1% of rating per minute...during commissioning, we test them at 10% per minute to be sure that they are there...that has to be held for a minute if the grid requires it.
Then there's the 5 minute hold, where a machine must remain in service (think it's 49Hz) for 5 minutes.
The biggest coal fired Station in Oz (connected to the grid, not islanded as per your paper) are 750MW units (4 in the station).
Each Unit is capable of sustained market operation at 7.5MW/Min raise lower, does 750MW during the day/peak, and drops to 150MW overnight, 20% of rated capacity.
They do it every night...they also have the capability of turning them off at night, and restarting in the morning (on turbine bypass) if market dictates...design life is 2,000+ hot starts.
Now explain how this is
a) impossible and
b) unsafe...
as per your quote.
Two types of response turtlevette.
The first is the governing margin that the Units are operating at. If the frequency drops, the governor opens the throttle valves, and the unit reacts...instantly, giving everything it can...and it's usually required to be about 10% of rated load...instantly. Advanced power plants will have bled steam throttling, or feedwater cut for additional short term capacity...that's 5 second max response. Failure to respond means fines.
a GT on standby will be there 5 minutes later.
Once the initial load is gained, the control system has to increase pressure and firing rate to sustain it...Oz system stability requirements are 1% of rating per minute...during commissioning, we test them at 10% per minute to be sure that they are there...that has to be held for a minute if the grid requires it.
Then there's the 5 minute hold, where a machine must remain in service (think it's 49Hz) for 5 minutes.
The biggest coal fired Station in Oz (connected to the grid, not islanded as per your paper) are 750MW units (4 in the station).
Each Unit is capable of sustained market operation at 7.5MW/Min raise lower, does 750MW during the day/peak, and drops to 150MW overnight, 20% of rated capacity.
They do it every night...they also have the capability of turning them off at night, and restarting in the morning (on turbine bypass) if market dictates...design life is 2,000+ hot starts.
Now explain how this is
a) impossible and
b) unsafe...
as per your quote.
I like this dashboard of what's running in the UK (and France). Time of posting, the UK demand is 43.53GW.
http://www.gridwatch.templar.co.uk/
Out of interest, if every Chevvy Volt ever sold was connected to the UK grid and discharged it's battery over an hour to help support it, it would add 0.0000035% to the grid...one off shot...releasing the same amount of power as OVERKILL's solar station produces in 9 mins.
http://www.gridwatch.templar.co.uk/
Out of interest, if every Chevvy Volt ever sold was connected to the UK grid and discharged it's battery over an hour to help support it, it would add 0.0000035% to the grid...one off shot...releasing the same amount of power as OVERKILL's solar station produces in 9 mins.
Originally Posted By: Al
Originally Posted By: SHOZ
You just plug it into the outlet.
Electricity is metered and comes off the transformers as 220V. You can't get that by pluging into a 120V receptacle.
The solar inverters are 12/24/48VDC in and 120c AC out. Yes you just plug it into an outlet to backfeed the house wiring. The panels is feed 2x120 at the top. So if you had more panels you would want to pick the other phase to help balance it out.
Originally Posted By: SHOZ
You just plug it into the outlet.
Electricity is metered and comes off the transformers as 220V. You can't get that by pluging into a 120V receptacle.
The solar inverters are 12/24/48VDC in and 120c AC out. Yes you just plug it into an outlet to backfeed the house wiring. The panels is feed 2x120 at the top. So if you had more panels you would want to pick the other phase to help balance it out.
Originally Posted By: turtlevette
Al said:Sure you can. It's 240 not 220. Half of 240 is 120. You have 2 legs of 120. Its all in the firing angle on the inverter. You sure can make power flow in either direction on any voltage level.
Whether the utility will accept it is another matter. But why tell them?
OK. I am not the arging mode. I am in the learning mode.
If you use a receptacle that comes off of say your right bus bar in your breaker panel and that's all you use and you have no other loads in your house will it go out into the grid and effectively turn the meter backward? Now if you used another solar panel and hooked it up to the left bus bar at the same time then, and only then could you operate things in your house like water heaters, range, 240 motors, etc. Presumably it would also turn the meter "backward"?
How does it synchronize with incoming power? Is its (square tooth cycle pattern I presume) just forced to adapt to the cycle timing of the grid? I could look all this up but I am sure you can provide a quicker answer.
I wonder how the electry supplier feels about a different wave form going back to their system? Probably ignorance is bliss or does it tryly matter. I suspect the second speculation is correct.
Thanks.
Originally Posted By: Donald
We really need to get nuclear fusion working so it puts out more than it needs as input. Everything else is just short term. Think of fusion as having the same kind of energy the sun puts out, just less of it and without the 93 million mile distance and inefficiency.
Watch a recent NOVA on volcanoes and consider that it might be nice to have a power source that did not depend upon the sun.
That will never happen in NY ... the controlling powers that be (NYC) are afraid of it. But they have no problem taking all of the power generated by the nuclear plants here in Upstate NY
Originally Posted By: OVERKILL
Originally Posted By: Rolla07
I doubt wind farms are any better
That's my point. We could have added the extra capacity to Darlington and been ahead of the game. Instead, we are left chasing the "green" pipe dreams which don't provide reliable power and don't last.
There was recently a wind farm put up by my parents. Unrelated, but I believe Donald brings one of his vehicles near there for rust proofing. MASSIVE government subsidy. I think the only people who made out are the people with (relatively) worthless farmland who now get paid a pretty good amount to house these and the "green" companies.
It is on top of a hill, so there is wind sometimes ... but when there is not wind, guess what happens - they have to take power OFF of the grid to keep turning. Seems like they take a good portion of what they make.
Solar isn't a viable option up here in NY, either. Especially around the time Winter starts. It's only sunny from about 7A-4P ... that doesn't seem like it would work so well.
If Fossil fuels are going away (and thanks to the anti fracking propaganda folks - the natural gas under NY state won't ever be used) our only viable options are nuclear or hydro. When I say "our", I mean Upstate NY. We generally don't have huge droughts and nuclear power ... well it's pretty reliable and efficient. The problems is all of the power generated here goes to NYC.
We really need to get nuclear fusion working so it puts out more than it needs as input. Everything else is just short term. Think of fusion as having the same kind of energy the sun puts out, just less of it and without the 93 million mile distance and inefficiency.
Watch a recent NOVA on volcanoes and consider that it might be nice to have a power source that did not depend upon the sun.
That will never happen in NY ... the controlling powers that be (NYC) are afraid of it. But they have no problem taking all of the power generated by the nuclear plants here in Upstate NY
Originally Posted By: OVERKILL
Originally Posted By: Rolla07
I doubt wind farms are any better
That's my point. We could have added the extra capacity to Darlington and been ahead of the game. Instead, we are left chasing the "green" pipe dreams which don't provide reliable power and don't last.
There was recently a wind farm put up by my parents. Unrelated, but I believe Donald brings one of his vehicles near there for rust proofing. MASSIVE government subsidy. I think the only people who made out are the people with (relatively) worthless farmland who now get paid a pretty good amount to house these and the "green" companies.
It is on top of a hill, so there is wind sometimes ... but when there is not wind, guess what happens - they have to take power OFF of the grid to keep turning. Seems like they take a good portion of what they make.
Solar isn't a viable option up here in NY, either. Especially around the time Winter starts. It's only sunny from about 7A-4P ... that doesn't seem like it would work so well.
If Fossil fuels are going away (and thanks to the anti fracking propaganda folks - the natural gas under NY state won't ever be used) our only viable options are nuclear or hydro. When I say "our", I mean Upstate NY. We generally don't have huge droughts and nuclear power ... well it's pretty reliable and efficient. The problems is all of the power generated here goes to NYC.
Originally Posted By: turtlevette
Whether the utility will accept it is another matter. But why tell them?
The same reason you shouldn't backfeed a generator by plugging it into a dryer outlet, in addition to the frequency and load balancing issues Al pointed out in his other post. These inverters you plug into a wall outlet are garbage and I would never recommend anyone use them. If you want to generate your own power, get some proper inverters hardwired to your panel or don't do it all.
And WHEN (not if) your utility finds out you're using these things, they will shut your power off and/or fine you until you agree to not use them anymore.
Whether the utility will accept it is another matter. But why tell them?
The same reason you shouldn't backfeed a generator by plugging it into a dryer outlet, in addition to the frequency and load balancing issues Al pointed out in his other post. These inverters you plug into a wall outlet are garbage and I would never recommend anyone use them. If you want to generate your own power, get some proper inverters hardwired to your panel or don't do it all.
And WHEN (not if) your utility finds out you're using these things, they will shut your power off and/or fine you until you agree to not use them anymore.
Here is what the seller had to say about their inverters regarding the sync and back feed.
It(inverter)is designed to sync(phase)to the grid power. If the grid goes down the inverter will also stop working which is required by law. You can not send power back into the grid if the utility is down for safety reasons. Thanks ,ML SOLAR
It(inverter)is designed to sync(phase)to the grid power. If the grid goes down the inverter will also stop working which is required by law. You can not send power back into the grid if the utility is down for safety reasons. Thanks ,ML SOLAR
Originally Posted By: Shannow
The biggest coal fired Station in Oz (connected to the grid, not islanded as per your paper) are 750MW units (4 in the station).
All of OZ can be considered an electrical island. It's all relative. You're whole system is puny compared to here. If we ever got 1 hz below 60 it'd be because the zombie apocalypse. The big boys have spinning reserve, ie a GT or other plant that is connected but generating almost nothing so there is no multi minute lag.
I think you'd agree some large steam turbines do not like being in certain frequency zones below their nominal design which makes it dangerous for the turbine. We've seen cracks in shafts here when operating turbines in rough zones for too long.
From a ramping standpoint boilers do not like to be ramped. Too much cold feed water shocks the system. Here we operate on 5% governor droop so each unit contributes a small portion of the frequency maintenance instead of having the governor go full open. I'd check with your operators to see if that is really true. Its called zero governor droop and only used in emergency situations here.
You operate your system differently. I'll accept that. You don't need to keep on to prove anything.
The biggest coal fired Station in Oz (connected to the grid, not islanded as per your paper) are 750MW units (4 in the station).
All of OZ can be considered an electrical island. It's all relative. You're whole system is puny compared to here. If we ever got 1 hz below 60 it'd be because the zombie apocalypse. The big boys have spinning reserve, ie a GT or other plant that is connected but generating almost nothing so there is no multi minute lag.
I think you'd agree some large steam turbines do not like being in certain frequency zones below their nominal design which makes it dangerous for the turbine. We've seen cracks in shafts here when operating turbines in rough zones for too long.
From a ramping standpoint boilers do not like to be ramped. Too much cold feed water shocks the system. Here we operate on 5% governor droop so each unit contributes a small portion of the frequency maintenance instead of having the governor go full open. I'd check with your operators to see if that is really true. Its called zero governor droop and only used in emergency situations here.
You operate your system differently. I'll accept that. You don't need to keep on to prove anything.
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