Based on the latest year's worth of *real data* from power generation across the contiguous United States (US48), what might be needed to displace medium- and high-CO2 power generation?
Regarding your comments about over-production of energy by renewable generating resources, is it not possible simply to balance this in real time by preventing the renewable resources from generating ? I can understand that it is difficult or impossible to switch nuclear or coal or gas fired thermal plants on and off rapidly. On the other hand can you not simply feather a wind generator and disconnect a PV panel? With the granular nature of wind and solar, it would be possible to do this with a fine level of adjustment. I do not really understand the problems of network balancing so maybe this is a stupid question.
The Balancing Authorities across all grids act to make sure electrical supply = electrical demand 60/24/365 to close tolerances, otherwise grid frequency is affected and that's bad. In the UK our grid operates at 50Hz (cycles per second) and the tolerance is a fraction of a Hz. I believe it's broadly similar in the US except the grid operates at 60 Hz.
"As supply and demand change, this impacts frequency. For example, if there’s more demand for electricity than supply then frequency will fall, but if supply is higher than demand, frequency will rise.
We’re required to routinely keep the frequency within one percent (0.5Hz) of 50Hz, but in aiming to meet that requirement we set ourselves a tighter operational target than required, and aim to maintain frequency within 0.2Hz of 50Hz in normal conditions."
It absolutely *is* possible to get a wind farm operator to adjust blade pitch etc. to adjust power, coordinated by the Balancing Authority.
My understanding is that it's *much* more difficult to turn solar farms down. If the power generated is not taken away safely, I guess really bad stuff happens. So solar tends to operate as negative load, which leads to 'duck curves' as less and less net load remains at peak output times.
Chris, is this the de-carbonisation of the current electricity generation grid? In other words, not transportation, heating, manufacturing, etc? Because those numbers would be far higher, I would guess. In the UK, if we converted all 28 million households' gas boilers (approx 30kW each) to electric (say, 10kW), that would be an extra 280GW load on the national grid, about 7 times the current size.
Hello Pat. Absolutely the post is about US48 electricity only. Take a look at the EIA website.
The UK 'plan' is for home heating to be provided using heat pumps not gas boilers. They use (round numbers) one third of the power, so e.g. a 10kW heat duty requires approx 3.3kW power. But that is still an increase in power consumption compared with 10kW of heat from burning gas.
Despite a lot of negative press, some data I've seen shows heat pumps *can* work fine in UK conditions - after all, they are very common in the Nordics. However, I don't think there is yet sufficient expertise among designers or technicians in the UK, so it's currently too much of a gamble for my liking.
Comments received via email Tuesday August 1 2023 9:35:32AM
"Looking forward to going through this obviously well researched info. On a VERY quick scan so far = this will be great to have some real numbers to support what I have been saying for over two years: 'they are greatly understating the time, the costs and the alternate environmental impacts for going 100% green/all electric.
Also, to Chris's comments on 'would the Grid be able to handle the transmission of all the new green electricity' = I have no hard numbers but would give 100:1 on any bet that the answer is currently NO WAY. As examples:
Last week in this current heat wave a major transmission company for 13 States declared a stage 1 emergency warning = They had less than the required reserve capacity.
Earlier this year California asked folks not to plug-in their EVs for a few days to recharge due to very high regional transmission/distribution demands.
Therefore, IF we have these issues now, now can you guess what would happen to the Grid if there were no gasoline/diesel cars and trucks only EVs; no gas stoves or hot water heaters only electric as the Biden Admin. is pushing towards.
Follow-up comments received via email Tuesday, 1 August 2023 at 21:07:57 BST
"Me again Chris, been doing some searches on the USA Grid; I would not have to pay on any bets.
The following two references show that current transmission/distribution cannot even support the current major heavy/medium truck fleets if all went to EV.
"Preparing grids for EV buses to enable a sustainable future. A contribution by Anthony Allard, Hitachi Energy Head of North America". Sustainable Bus. 2022-08-12. Retrieved 2022-08-28.
"Fleet Electrification Provides Great Opportunity — If Done Right". www.utilityproducts.com. 2022-05-13. Retrieved 2022-08-28.
Also here is an attached pdf [CB- not attd. in this copied comment], which indicates major east-west interconnection additions are needed IF the USA wants to keep costs down and ensure future stability etc.
Finally, I found a reference today that this past weekend none other than Elon Musk is predicting that the USA electricity demand will " triple by 2045"! He notes not only EVs but for all the AI computing systems = ?
I'd be interested to know why you can't simply disconnect a PV panel. The energy input is limited to the solar radiation falling on it and there is no energy being created in the panel. There is no energy being stored in the panel except as heat. The panel will get a bit hotter than it would if some energy is being taken off as electricity but I don't see why it should get any hotter than any other dark object in full sunlight.
I had a look too. There is a lot of stuff from non scientific and non engineering sources that I don't think you can set much store by. Some say yes, some say no. The problem with the Internet is there are often so many layers of rubbish to get through before you get to anything useful. I haven't found anything scientific or engineering yet. There is a difference between disconnecting and disconnecting under load. It is always touchy to disconnect stuff under load but it is done even at high tension. But we are not talking high tension here. Maybe disconnecting under load might create a spike which would damage the cells? Surely something which could be managed. After all a PWM controller is just a switch. I suspect there might be an financial reason why they dont want to switch off. After all, if you switch off you don't get paid.
The key to it may be related to your original "balance this in real time" comment?
In real time poss = middle of the day when the panels are all generating.
Disconnect them from the load and they are still generating that DC potential... which (I am guessing) is when you can get an arc flash discharge at a 'weak point' in the system.
So (I am still guessing) if the Balancing Authority plans ahead 24 hours and decides they don't want the output from that farm, they tell them while it's still dark... maybe?
Or maybe the commercial agreements give Solar PV farms first preference regardless, hence duck curves...?
I don't think residential users would be encouraged to try to throttle / turn off their output middle of the day for same reasons but even worse because of safety implications. Of course there'll be an 'off' switch/breaker but presumably extreme caution advised.
Regarding your comments about over-production of energy by renewable generating resources, is it not possible simply to balance this in real time by preventing the renewable resources from generating ? I can understand that it is difficult or impossible to switch nuclear or coal or gas fired thermal plants on and off rapidly. On the other hand can you not simply feather a wind generator and disconnect a PV panel? With the granular nature of wind and solar, it would be possible to do this with a fine level of adjustment. I do not really understand the problems of network balancing so maybe this is a stupid question.
Hello Andrew, thank you for your comments.
The Balancing Authorities across all grids act to make sure electrical supply = electrical demand 60/24/365 to close tolerances, otherwise grid frequency is affected and that's bad. In the UK our grid operates at 50Hz (cycles per second) and the tolerance is a fraction of a Hz. I believe it's broadly similar in the US except the grid operates at 60 Hz.
Our grid operator has this info on their website: https://www.nationalgrideso.com/electricity-explained/how-do-we-balance-grid
Under frequency they say:
"As supply and demand change, this impacts frequency. For example, if there’s more demand for electricity than supply then frequency will fall, but if supply is higher than demand, frequency will rise.
We’re required to routinely keep the frequency within one percent (0.5Hz) of 50Hz, but in aiming to meet that requirement we set ourselves a tighter operational target than required, and aim to maintain frequency within 0.2Hz of 50Hz in normal conditions."
It absolutely *is* possible to get a wind farm operator to adjust blade pitch etc. to adjust power, coordinated by the Balancing Authority.
My understanding is that it's *much* more difficult to turn solar farms down. If the power generated is not taken away safely, I guess really bad stuff happens. So solar tends to operate as negative load, which leads to 'duck curves' as less and less net load remains at peak output times.
I hope that makes sense.
Chris, is this the de-carbonisation of the current electricity generation grid? In other words, not transportation, heating, manufacturing, etc? Because those numbers would be far higher, I would guess. In the UK, if we converted all 28 million households' gas boilers (approx 30kW each) to electric (say, 10kW), that would be an extra 280GW load on the national grid, about 7 times the current size.
Hello Pat. Absolutely the post is about US48 electricity only. Take a look at the EIA website.
The UK 'plan' is for home heating to be provided using heat pumps not gas boilers. They use (round numbers) one third of the power, so e.g. a 10kW heat duty requires approx 3.3kW power. But that is still an increase in power consumption compared with 10kW of heat from burning gas.
Despite a lot of negative press, some data I've seen shows heat pumps *can* work fine in UK conditions - after all, they are very common in the Nordics. However, I don't think there is yet sufficient expertise among designers or technicians in the UK, so it's currently too much of a gamble for my liking.
Comments received via email Tuesday August 1 2023 9:35:32AM
"Looking forward to going through this obviously well researched info. On a VERY quick scan so far = this will be great to have some real numbers to support what I have been saying for over two years: 'they are greatly understating the time, the costs and the alternate environmental impacts for going 100% green/all electric.
Also, to Chris's comments on 'would the Grid be able to handle the transmission of all the new green electricity' = I have no hard numbers but would give 100:1 on any bet that the answer is currently NO WAY. As examples:
Last week in this current heat wave a major transmission company for 13 States declared a stage 1 emergency warning = They had less than the required reserve capacity.
Earlier this year California asked folks not to plug-in their EVs for a few days to recharge due to very high regional transmission/distribution demands.
Therefore, IF we have these issues now, now can you guess what would happen to the Grid if there were no gasoline/diesel cars and trucks only EVs; no gas stoves or hot water heaters only electric as the Biden Admin. is pushing towards.
Hope Chris keeps up the information flow.
Cheers, John"
Follow-up comments received via email Tuesday, 1 August 2023 at 21:07:57 BST
"Me again Chris, been doing some searches on the USA Grid; I would not have to pay on any bets.
The following two references show that current transmission/distribution cannot even support the current major heavy/medium truck fleets if all went to EV.
"Preparing grids for EV buses to enable a sustainable future. A contribution by Anthony Allard, Hitachi Energy Head of North America". Sustainable Bus. 2022-08-12. Retrieved 2022-08-28.
"Fleet Electrification Provides Great Opportunity — If Done Right". www.utilityproducts.com. 2022-05-13. Retrieved 2022-08-28.
Also here is an attached pdf [CB- not attd. in this copied comment], which indicates major east-west interconnection additions are needed IF the USA wants to keep costs down and ensure future stability etc.
Finally, I found a reference today that this past weekend none other than Elon Musk is predicting that the USA electricity demand will " triple by 2045"! He notes not only EVs but for all the AI computing systems = ?
Cheers, John"
I'd be interested to know why you can't simply disconnect a PV panel. The energy input is limited to the solar radiation falling on it and there is no energy being created in the panel. There is no energy being stored in the panel except as heat. The panel will get a bit hotter than it would if some energy is being taken off as electricity but I don't see why it should get any hotter than any other dark object in full sunlight.
I searched and came up with this:
https://solvoltaics.com/disconnecting-solar-panel-under-load/
Sun => electricity => arc, electrocution, bad stuff.
There were quite a few results for a search "disconnecting solar panels under load" - and most seemed to come with similar warnings.
I had a look too. There is a lot of stuff from non scientific and non engineering sources that I don't think you can set much store by. Some say yes, some say no. The problem with the Internet is there are often so many layers of rubbish to get through before you get to anything useful. I haven't found anything scientific or engineering yet. There is a difference between disconnecting and disconnecting under load. It is always touchy to disconnect stuff under load but it is done even at high tension. But we are not talking high tension here. Maybe disconnecting under load might create a spike which would damage the cells? Surely something which could be managed. After all a PWM controller is just a switch. I suspect there might be an financial reason why they dont want to switch off. After all, if you switch off you don't get paid.
Hi Andrew, agreed.
The key to it may be related to your original "balance this in real time" comment?
In real time poss = middle of the day when the panels are all generating.
Disconnect them from the load and they are still generating that DC potential... which (I am guessing) is when you can get an arc flash discharge at a 'weak point' in the system.
So (I am still guessing) if the Balancing Authority plans ahead 24 hours and decides they don't want the output from that farm, they tell them while it's still dark... maybe?
Or maybe the commercial agreements give Solar PV farms first preference regardless, hence duck curves...?
I don't think residential users would be encouraged to try to throttle / turn off their output middle of the day for same reasons but even worse because of safety implications. Of course there'll be an 'off' switch/breaker but presumably extreme caution advised.