Something occurred to me.
In the old days we had tons and tons and TONS of spinning mass in the generators. This gave short term frequency stability in the grid - if
the frequency shifted a little bit all those tons had to speed up or
slow down to match, and as they did so they stopped it changing very
fast. Even if the grid waveform wasn't a sine wave they'd be correcting automatically.
We don't have as much spinning mass any more. As Spain has gone to
almost all "renewables" they've got *** all.
If you put me into a project designing the software to control an
inverter to change DC output from a solar farm or a windfarm into AC for
the grid I'd be monitoring the grid frequency so that I knew when I
ought to be putting power into the grid. This varies at 50Hz, and
doubtless has all sorts of higher frequency stuff laid on top which must
be ignored.
Suppose I got it slightly wrong, and my reaction to grid frequency
variations was a little bit slow. I put out my 50Hz power wave, monitor
the outgoing current, and if it isn't quite lined up with the sine wave
I expect I tweak the commands I send to the inverter.
But having got it slightly wrong there's a lag. Which means that when
the frequency drops I only start trying to push it back a few seconds
later. And similarly when it rises.
And suppose that software like this is running in all the inverters in
the entire grid.
The frequency drops a little. All the inverters notice, and push it back faster. Not quite at once, but a couple of seconds later.
Which means that the frequency rises. Perhaps a little higher than 50Hz.
All the inverters notice this, and push it back slower. After a few
seconds. And it overshoots again. And again. And again... A classic
positive feedback loop.
In the end a couple of them give up and turn off. Then some more.
And suddenly Spain is in darkness.
Andy
Something occurred to me.
In the old days we had tons and tons and TONS of spinning mass in the generators. This gave short term frequency stability in the grid - if
the frequency shifted a little bit all those tons had to speed up or
slow down to match, and as they did so they stopped it changing very
fast. Even if the grid waveform wasn't a sine wave they'd be correcting automatically.
We don't have as much spinning mass any more. As Spain has gone to
almost all "renewables" they've got *** all.
If you put me into a project designing the software to control an
inverter to change DC output from a solar farm or a windfarm into AC for
the grid I'd be monitoring the grid frequency so that I knew when I
ought to be putting power into the grid. This varies at 50Hz, and
doubtless has all sorts of higher frequency stuff laid on top which must
be ignored.
Suppose I got it slightly wrong, and my reaction to grid frequency
variations was a little bit slow. I put out my 50Hz power wave, monitor
the outgoing current, and if it isn't quite lined up with the sine wave
I expect I tweak the commands I send to the inverter.
But having got it slightly wrong there's a lag. Which means that when
the frequency drops I only start trying to push it back a few seconds
later. And similarly when it rises.
And suppose that software like this is running in all the inverters in
the entire grid.
The frequency drops a little. All the inverters notice, and push it back faster. Not quite at once, but a couple of seconds later.
Which means that the frequency rises. Perhaps a little higher than 50Hz.
All the inverters notice this, and push it back slower. After a few
seconds. And it overshoots again. And again. And again... A classic
positive feedback loop.
In the end a couple of them give up and turn off. Then some more.
And suddenly Spain is in darkness.
Andy
On 2025-05-07 11:28, Vir Campestris wrote:
Something occurred to me.
In the old days we had tons and tons and TONS of spinning mass in the
generators. This gave short term frequency stability in the grid - if
the frequency shifted a little bit all those tons had to speed up or
slow down to match, and as they did so they stopped it changing very
fast. Even if the grid waveform wasn't a sine wave they'd be
correcting automatically.
We don't have as much spinning mass any more. As Spain has gone to
almost all "renewables" they've got *** all.
If you put me into a project designing the software to control an
inverter to change DC output from a solar farm or a windfarm into AC
for the grid I'd be monitoring the grid frequency so that I knew when
I ought to be putting power into the grid. This varies at 50Hz, and
doubtless has all sorts of higher frequency stuff laid on top which
must be ignored.
Suppose I got it slightly wrong, and my reaction to grid frequency
variations was a little bit slow. I put out my 50Hz power wave,
monitor the outgoing current, and if it isn't quite lined up with the
sine wave I expect I tweak the commands I send to the inverter.
But having got it slightly wrong there's a lag. Which means that when
the frequency drops I only start trying to push it back a few seconds
later. And similarly when it rises.
And suppose that software like this is running in all the inverters in
the entire grid.
The frequency drops a little. All the inverters notice, and push it
back faster. Not quite at once, but a couple of seconds later.
Which means that the frequency rises. Perhaps a little higher than 50Hz.
All the inverters notice this, and push it back slower. After a few
seconds. And it overshoots again. And again. And again... A classic
positive feedback loop.
In the end a couple of them give up and turn off. Then some more.
And suddenly Spain is in darkness.
Andy
So:
make then react faster?
add some energy storage (small capacity but high instantaneous current)
so that they can work both ways, very short term adding or subtracting,
just as the rotating mass does? Needs a bi-directional inverter, but
they seem to be a thing already.
nib
On 07/05/2025 12:38, nib wrote:
On 2025-05-07 11:28, Vir Campestris wrote:Yep. The key is that the inverters are no good without the storage
Something occurred to me.
In the old days we had tons and tons and TONS of spinning mass in the
generators. This gave short term frequency stability in the grid - if
the frequency shifted a little bit all those tons had to speed up or
slow down to match, and as they did so they stopped it changing very
fast. Even if the grid waveform wasn't a sine wave they'd be
correcting automatically.
We don't have as much spinning mass any more. As Spain has gone to
almost all "renewables" they've got *** all.
If you put me into a project designing the software to control an
inverter to change DC output from a solar farm or a windfarm into AC
for the grid I'd be monitoring the grid frequency so that I knew when
I ought to be putting power into the grid. This varies at 50Hz, and
doubtless has all sorts of higher frequency stuff laid on top which
must be ignored.
Suppose I got it slightly wrong, and my reaction to grid frequency
variations was a little bit slow. I put out my 50Hz power wave,
monitor the outgoing current, and if it isn't quite lined up with the
sine wave I expect I tweak the commands I send to the inverter.
But having got it slightly wrong there's a lag. Which means that when
the frequency drops I only start trying to push it back a few seconds
later. And similarly when it rises.
And suppose that software like this is running in all the inverters in
the entire grid.
The frequency drops a little. All the inverters notice, and push it
back faster. Not quite at once, but a couple of seconds later.
Which means that the frequency rises. Perhaps a little higher than 50Hz. >>>
All the inverters notice this, and push it back slower. After a few
seconds. And it overshoots again. And again. And again... A classic
positive feedback loop.
In the end a couple of them give up and turn off. Then some more.
And suddenly Spain is in darkness.
Andy
So:
make then react faster?
add some energy storage (small capacity but high instantaneous current)
so that they can work both ways, very short term adding or subtracting,
just as the rotating mass does? Needs a bi-directional inverter, but
they seem to be a thing already.
Which is just another reason why wind and solar are a crock of shit
The Natural Philosopher <tnp@invalid.invalid> wrote:
On 07/05/2025 12:38, nib wrote:
On 2025-05-07 11:28, Vir Campestris wrote:Yep. The key is that the inverters are no good without the storage
Something occurred to me.
In the old days we had tons and tons and TONS of spinning mass in the
generators. This gave short term frequency stability in the grid - if
the frequency shifted a little bit all those tons had to speed up or
slow down to match, and as they did so they stopped it changing very
fast. Even if the grid waveform wasn't a sine wave they'd be
correcting automatically.
We don't have as much spinning mass any more. As Spain has gone to
almost all "renewables" they've got *** all.
If you put me into a project designing the software to control an
inverter to change DC output from a solar farm or a windfarm into AC
for the grid I'd be monitoring the grid frequency so that I knew when
I ought to be putting power into the grid. This varies at 50Hz, and
doubtless has all sorts of higher frequency stuff laid on top which
must be ignored.
Suppose I got it slightly wrong, and my reaction to grid frequency
variations was a little bit slow. I put out my 50Hz power wave,
monitor the outgoing current, and if it isn't quite lined up with the
sine wave I expect I tweak the commands I send to the inverter.
But having got it slightly wrong there's a lag. Which means that when
the frequency drops I only start trying to push it back a few seconds
later. And similarly when it rises.
And suppose that software like this is running in all the inverters in >>>> the entire grid.
The frequency drops a little. All the inverters notice, and push it
back faster. Not quite at once, but a couple of seconds later.
Which means that the frequency rises. Perhaps a little higher than 50Hz. >>>>
All the inverters notice this, and push it back slower. After a few
seconds. And it overshoots again. And again. And again... A classic
positive feedback loop.
In the end a couple of them give up and turn off. Then some more.
And suddenly Spain is in darkness.
Andy
So:
make then react faster?
add some energy storage (small capacity but high instantaneous current)
so that they can work both ways, very short term adding or subtracting,
just as the rotating mass does? Needs a bi-directional inverter, but
they seem to be a thing already.
Which is just another reason why wind and solar are a crock of shit
Orsted pulls out of huge wind farm due to high costs:
Quote:
Orsted said the project no longer made economic sense, despite signing a 15-year contract with the UK government guaranteeing to sell power at an agreed price.
[…]
Just over half of the country's power currently comes from wind, solar, nuclear and biomass – organic matter. The government wants to raise that to 95% by 2030 – so in just five years' time.
In order to meet that target the UK will need to triple offshore wind capacity and double the amount of solar and onshore wind power on the
system, according to estimates by Aurora Energy.
It will also need a significant upgrade to the electricity grid with 620 miles of new power lines as well as substations and other equipment.
Unquote
<https://www.bbc.co.uk/news/articles/ce848g8l8vro>
The Natural Philosopher <tnp@invalid.invalid> wrote:
On 07/05/2025 12:38, nib wrote:
On 2025-05-07 11:28, Vir Campestris wrote:Yep. The key is that the inverters are no good without the storage
Something occurred to me.
In the old days we had tons and tons and TONS of spinning mass in the
generators. This gave short term frequency stability in the grid - if
the frequency shifted a little bit all those tons had to speed up or
slow down to match, and as they did so they stopped it changing very
fast. Even if the grid waveform wasn't a sine wave they'd be
correcting automatically.
We don't have as much spinning mass any more. As Spain has gone to
almost all "renewables" they've got *** all.
If you put me into a project designing the software to control an
inverter to change DC output from a solar farm or a windfarm into AC
for the grid I'd be monitoring the grid frequency so that I knew when
I ought to be putting power into the grid. This varies at 50Hz, and
doubtless has all sorts of higher frequency stuff laid on top which
must be ignored.
Suppose I got it slightly wrong, and my reaction to grid frequency
variations was a little bit slow. I put out my 50Hz power wave,
monitor the outgoing current, and if it isn't quite lined up with the
sine wave I expect I tweak the commands I send to the inverter.
But having got it slightly wrong there's a lag. Which means that when
the frequency drops I only start trying to push it back a few seconds
later. And similarly when it rises.
And suppose that software like this is running in all the inverters in >>>> the entire grid.
The frequency drops a little. All the inverters notice, and push it
back faster. Not quite at once, but a couple of seconds later.
Which means that the frequency rises. Perhaps a little higher than 50Hz. >>>>
All the inverters notice this, and push it back slower. After a few
seconds. And it overshoots again. And again. And again... A classic
positive feedback loop.
In the end a couple of them give up and turn off. Then some more.
And suddenly Spain is in darkness.
Andy
So:
make then react faster?
add some energy storage (small capacity but high instantaneous current)
so that they can work both ways, very short term adding or subtracting,
just as the rotating mass does? Needs a bi-directional inverter, but
they seem to be a thing already.
Which is just another reason why wind and solar are a crock of shit
Orsted pulls out of huge wind farm due to high costs:
Quote:
Orsted said the project no longer made economic sense, despite signing a 15-year contract with the UK government guaranteeing to sell power at an agreed price.
[…]
Just over half of the country's power currently comes from wind, solar, nuclear and biomass – organic matter. The government wants to raise that to 95% by 2030 – so in just five years' time.
In order to meet that target the UK will need to triple offshore wind capacity and double the amount of solar and onshore wind power on the
system, according to estimates by Aurora Energy.
It will also need a significant upgrade to the electricity grid with 620 miles of new power lines as well as substations and other equipment.
Unquote
<https://www.bbc.co.uk/news/articles/ce848g8l8vro>
On 07/05/2025 18:15, Spike wrote:
The Natural Philosopher <tnp@invalid.invalid> wrote:
On 07/05/2025 12:38, nib wrote:
On 2025-05-07 11:28, Vir Campestris wrote:Yep. The key is that the inverters are no good without the storage
Something occurred to me.
In the old days we had tons and tons and TONS of spinning mass in the >>>>> generators. This gave short term frequency stability in the grid - if >>>>> the frequency shifted a little bit all those tons had to speed up or >>>>> slow down to match, and as they did so they stopped it changing very >>>>> fast. Even if the grid waveform wasn't a sine wave they'd be
correcting automatically.
We don't have as much spinning mass any more. As Spain has gone to
almost all "renewables" they've got *** all.
If you put me into a project designing the software to control an
inverter to change DC output from a solar farm or a windfarm into AC >>>>> for the grid I'd be monitoring the grid frequency so that I knew when >>>>> I ought to be putting power into the grid. This varies at 50Hz, and
doubtless has all sorts of higher frequency stuff laid on top which
must be ignored.
Suppose I got it slightly wrong, and my reaction to grid frequency
variations was a little bit slow. I put out my 50Hz power wave,
monitor the outgoing current, and if it isn't quite lined up with the >>>>> sine wave I expect I tweak the commands I send to the inverter.
But having got it slightly wrong there's a lag. Which means that when >>>>> the frequency drops I only start trying to push it back a few seconds >>>>> later. And similarly when it rises.
And suppose that software like this is running in all the inverters in >>>>> the entire grid.
The frequency drops a little. All the inverters notice, and push it
back faster. Not quite at once, but a couple of seconds later.
Which means that the frequency rises. Perhaps a little higher than
50Hz.
All the inverters notice this, and push it back slower. After a few
seconds. And it overshoots again. And again. And again... A classic
positive feedback loop.
In the end a couple of them give up and turn off. Then some more.
And suddenly Spain is in darkness.
Andy
So:
make then react faster?
add some energy storage (small capacity but high instantaneous current) >>>> so that they can work both ways, very short term adding or subtracting, >>>> just as the rotating mass does? Needs a bi-directional inverter, but
they seem to be a thing already.
Which is just another reason why wind and solar are a crock of shit
Orsted pulls out of huge wind farm due to high costs:
Quote:
Orsted said the project no longer made economic sense, despite signing a
15-year contract with the UK government guaranteeing to sell power at an
agreed price.
[…]
Just over half of the country's power currently comes from wind, solar,
nuclear and biomass – organic matter. The government wants to raise
that to
95% by 2030 – so in just five years' time.
In order to meet that target the UK will need to triple offshore wind
capacity and double the amount of solar and onshore wind power on the
system, according to estimates by Aurora Energy.
It will also need a significant upgrade to the electricity grid with 620
miles of new power lines as well as substations and other equipment.
Unquote
<https://www.bbc.co.uk/news/articles/ce848g8l8vro>
Don't worry, HMG will just find a way of increasing electricity
prices even more to slip another lucrative long-term bung to Orsted.
On 2025-05-07 19:36, Andrew wrote:It seems deliberately obfuscating and hand wavey to me.
On 07/05/2025 18:15, Spike wrote:
The Natural Philosopher <tnp@invalid.invalid> wrote:
On 07/05/2025 12:38, nib wrote:
On 2025-05-07 11:28, Vir Campestris wrote:Yep. The key is that the inverters are no good without the storage
Something occurred to me.
In the old days we had tons and tons and TONS of spinning mass in the >>>>>> generators. This gave short term frequency stability in the grid - if >>>>>> the frequency shifted a little bit all those tons had to speed up or >>>>>> slow down to match, and as they did so they stopped it changing very >>>>>> fast. Even if the grid waveform wasn't a sine wave they'd be
correcting automatically.
We don't have as much spinning mass any more. As Spain has gone to >>>>>> almost all "renewables" they've got *** all.
If you put me into a project designing the software to control an
inverter to change DC output from a solar farm or a windfarm into AC >>>>>> for the grid I'd be monitoring the grid frequency so that I knew when >>>>>> I ought to be putting power into the grid. This varies at 50Hz, and >>>>>> doubtless has all sorts of higher frequency stuff laid on top which >>>>>> must be ignored.
Suppose I got it slightly wrong, and my reaction to grid frequency >>>>>> variations was a little bit slow. I put out my 50Hz power wave,
monitor the outgoing current, and if it isn't quite lined up with the >>>>>> sine wave I expect I tweak the commands I send to the inverter.
But having got it slightly wrong there's a lag. Which means that when >>>>>> the frequency drops I only start trying to push it back a few seconds >>>>>> later. And similarly when it rises.
And suppose that software like this is running in all the
inverters in
the entire grid.
The frequency drops a little. All the inverters notice, and push it >>>>>> back faster. Not quite at once, but a couple of seconds later.
Which means that the frequency rises. Perhaps a little higher than >>>>>> 50Hz.
All the inverters notice this, and push it back slower. After a few >>>>>> seconds. And it overshoots again. And again. And again... A classic >>>>>> positive feedback loop.
In the end a couple of them give up and turn off. Then some more.
And suddenly Spain is in darkness.
Andy
So:
make then react faster?
add some energy storage (small capacity but high instantaneous
current)
so that they can work both ways, very short term adding or
subtracting,
just as the rotating mass does? Needs a bi-directional inverter, but >>>>> they seem to be a thing already.
Which is just another reason why wind and solar are a crock of shit
Orsted pulls out of huge wind farm due to high costs:
Quote:
Orsted said the project no longer made economic sense, despite signing a >>> 15-year contract with the UK government guaranteeing to sell power at an >>> agreed price.
[…]
Just over half of the country's power currently comes from wind, solar,
nuclear and biomass – organic matter. The government wants to raise
that to
95% by 2030 – so in just five years' time.
In order to meet that target the UK will need to triple offshore wind
capacity and double the amount of solar and onshore wind power on the
system, according to estimates by Aurora Energy.
It will also need a significant upgrade to the electricity grid with 620 >>> miles of new power lines as well as substations and other equipment.
Unquote
<https://www.bbc.co.uk/news/articles/ce848g8l8vro>
Don't worry, HMG will just find a way of increasing electricity
prices even more to slip another lucrative long-term bung to Orsted.
A summary of grid inertia that I found useful:
https://docs.nrel.gov/docs/fy20osti/73856.pdf
(Though it appears to have been written by "greens" so maybe not allowed here!)
nib
On 08/05/2025 11:24, nib wrote:
On 2025-05-07 19:36, Andrew wrote:It seems deliberately obfuscating and hand wavey to me.
On 07/05/2025 18:15, Spike wrote:
The Natural Philosopher <tnp@invalid.invalid> wrote:
On 07/05/2025 12:38, nib wrote:
On 2025-05-07 11:28, Vir Campestris wrote:Yep. The key is that the inverters are no good without the storage
Something occurred to me.
In the old days we had tons and tons and TONS of spinning mass in >>>>>>> the
generators. This gave short term frequency stability in the grid >>>>>>> - if
the frequency shifted a little bit all those tons had to speed up or >>>>>>> slow down to match, and as they did so they stopped it changing very >>>>>>> fast. Even if the grid waveform wasn't a sine wave they'd be
correcting automatically.
We don't have as much spinning mass any more. As Spain has gone to >>>>>>> almost all "renewables" they've got *** all.
If you put me into a project designing the software to control an >>>>>>> inverter to change DC output from a solar farm or a windfarm into AC >>>>>>> for the grid I'd be monitoring the grid frequency so that I knew >>>>>>> when
I ought to be putting power into the grid. This varies at 50Hz, and >>>>>>> doubtless has all sorts of higher frequency stuff laid on top which >>>>>>> must be ignored.
Suppose I got it slightly wrong, and my reaction to grid frequency >>>>>>> variations was a little bit slow. I put out my 50Hz power wave,
monitor the outgoing current, and if it isn't quite lined up with >>>>>>> the
sine wave I expect I tweak the commands I send to the inverter.
But having got it slightly wrong there's a lag. Which means that >>>>>>> when
the frequency drops I only start trying to push it back a few
seconds
later. And similarly when it rises.
And suppose that software like this is running in all the
inverters in
the entire grid.
The frequency drops a little. All the inverters notice, and push it >>>>>>> back faster. Not quite at once, but a couple of seconds later.
Which means that the frequency rises. Perhaps a little higher
than 50Hz.
All the inverters notice this, and push it back slower. After a few >>>>>>> seconds. And it overshoots again. And again. And again... A classic >>>>>>> positive feedback loop.
In the end a couple of them give up and turn off. Then some more. >>>>>>>
And suddenly Spain is in darkness.
Andy
So:
make then react faster?
add some energy storage (small capacity but high instantaneous
current)
so that they can work both ways, very short term adding or
subtracting,
just as the rotating mass does? Needs a bi-directional inverter, but >>>>>> they seem to be a thing already.
Which is just another reason why wind and solar are a crock of shit
Orsted pulls out of huge wind farm due to high costs:
Quote:
Orsted said the project no longer made economic sense, despite
signing a
15-year contract with the UK government guaranteeing to sell power
at an
agreed price.
[…]
Just over half of the country's power currently comes from wind, solar, >>>> nuclear and biomass – organic matter. The government wants to raise
that to
95% by 2030 – so in just five years' time.
In order to meet that target the UK will need to triple offshore wind
capacity and double the amount of solar and onshore wind power on the
system, according to estimates by Aurora Energy.
It will also need a significant upgrade to the electricity grid with
620
miles of new power lines as well as substations and other equipment.
Unquote
<https://www.bbc.co.uk/news/articles/ce848g8l8vro>
Don't worry, HMG will just find a way of increasing electricity
prices even more to slip another lucrative long-term bung to Orsted.
A summary of grid inertia that I found useful:
https://docs.nrel.gov/docs/fy20osti/73856.pdf
(Though it appears to have been written by "greens" so maybe not
allowed here!)
nib
On 5/8/25 13:10, The Natural Philosopher wrote:
On 08/05/2025 11:24, nib wrote:Seemed okish to me.
On 2025-05-07 19:36, Andrew wrote:It seems deliberately obfuscating and hand wavey to me.
On 07/05/2025 18:15, Spike wrote:
The Natural Philosopher <tnp@invalid.invalid> wrote:
On 07/05/2025 12:38, nib wrote:Orsted pulls out of huge wind farm due to high costs:
On 2025-05-07 11:28, Vir Campestris wrote:Yep. The key is that the inverters are no good without the storage >>>>>>
Something occurred to me.
In the old days we had tons and tons and TONS of spinning mass >>>>>>>> in the
generators. This gave short term frequency stability in the grid >>>>>>>> - if
the frequency shifted a little bit all those tons had to speed >>>>>>>> up or
slow down to match, and as they did so they stopped it changing >>>>>>>> very
fast. Even if the grid waveform wasn't a sine wave they'd be
correcting automatically.
We don't have as much spinning mass any more. As Spain has gone to >>>>>>>> almost all "renewables" they've got *** all.
If you put me into a project designing the software to control an >>>>>>>> inverter to change DC output from a solar farm or a windfarm
into AC
for the grid I'd be monitoring the grid frequency so that I knew >>>>>>>> when
I ought to be putting power into the grid. This varies at 50Hz, and >>>>>>>> doubtless has all sorts of higher frequency stuff laid on top which >>>>>>>> must be ignored.
Suppose I got it slightly wrong, and my reaction to grid frequency >>>>>>>> variations was a little bit slow. I put out my 50Hz power wave, >>>>>>>> monitor the outgoing current, and if it isn't quite lined up
with the
sine wave I expect I tweak the commands I send to the inverter. >>>>>>>>
But having got it slightly wrong there's a lag. Which means that >>>>>>>> when
the frequency drops I only start trying to push it back a few
seconds
later. And similarly when it rises.
And suppose that software like this is running in all the
inverters in
the entire grid.
The frequency drops a little. All the inverters notice, and push it >>>>>>>> back faster. Not quite at once, but a couple of seconds later. >>>>>>>>
Which means that the frequency rises. Perhaps a little higher
than 50Hz.
All the inverters notice this, and push it back slower. After a few >>>>>>>> seconds. And it overshoots again. And again. And again... A classic >>>>>>>> positive feedback loop.
In the end a couple of them give up and turn off. Then some more. >>>>>>>>
And suddenly Spain is in darkness.
Andy
So:
make then react faster?
add some energy storage (small capacity but high instantaneous
current)
so that they can work both ways, very short term adding or
subtracting,
just as the rotating mass does? Needs a bi-directional inverter, but >>>>>>> they seem to be a thing already.
Which is just another reason why wind and solar are a crock of shit >>>>>
Quote:
Orsted said the project no longer made economic sense, despite
signing a
15-year contract with the UK government guaranteeing to sell power
at an
agreed price.
[…]
Just over half of the country's power currently comes from wind,
solar,
nuclear and biomass – organic matter. The government wants to raise >>>>> that to
95% by 2030 – so in just five years' time.
In order to meet that target the UK will need to triple offshore wind >>>>> capacity and double the amount of solar and onshore wind power on the >>>>> system, according to estimates by Aurora Energy.
It will also need a significant upgrade to the electricity grid
with 620
miles of new power lines as well as substations and other equipment. >>>>> Unquote
<https://www.bbc.co.uk/news/articles/ce848g8l8vro>
Don't worry, HMG will just find a way of increasing electricity
prices even more to slip another lucrative long-term bung to Orsted.
A summary of grid inertia that I found useful:
https://docs.nrel.gov/docs/fy20osti/73856.pdf
(Though it appears to have been written by "greens" so maybe not
allowed here!)
nib
It made clear, to me, that in the new world, inverters should not just
follow grid frequency but should be responsible for establishing and maintaining grid voltage and frequency. i.e. they should dictate frequency.
The problem in the old world was that turbines could only increase
mechanical power slowly, what they called primary frequency response
(PFR). This is effectively how fast they can generate extra power from
extra gas, akin to how fast a car engine responds to stepping on the accelerator. With traditional turbine generators, this is a 0.3%-2%
increase per second. So, using these figures, it might take a generator 15-100 seconds to increase from 60% to 90% output. Too slow, which is
why you need inertia if a power plant suddenly drops off the grid in an instant.
However, inverters can have a much faster response, going from 0 to 100%
in 0.5 seconds.
So we don't need inverters to have inertia, we just need them to have
spare headroom to *generate extra power*
and for them to dictate grid
frequency rather than just follow it. Batteries can produce sudden
bursts of extra power, when needed.
This whole thing isn't about any great technological difficulty, it is
just about politicians/grid controllers cost-cutting, delaying making
the changes they know are needed. i.e. It is due to politics not science.
Not a conclusion that will surprise many here.
and for them to dictate grid frequency rather than just follow it.All masters and no slaves. Fighting each other.
Batteries can produce sudden bursts of extra power, when needed.
Yes, batteries can, but they are expensive addons to an already
fiendishly over budget technology
You cant have many inverters dictating frequency. The Grid is one synchronised thing and everybody has to synch to it. No one generator
sets the pace.
What happens is that as frequency drop more power is fed
into to fossil and hydro turbines to restore it. Because they run off
stored energy. But they are not themselves master clocks. The guts
running the grid are simply doing their job adding more power up to the
max when demand calls for it and easing back if the grid overspeeds.
Renewables can't do that.
Battery packs can BUT the peak power demands are very high which makes
for a very expensive set of batteries.
This whole thing isn't about any great technological difficulty, it is
just about politicians/grid controllers cost-cutting, delaying making
the changes they know are needed. i.e. It is due to politics not science.
In this case it is exactly about technology and about cost. As well as politics and profit
You cant have many inverters dictating frequency. The Grid is one synchronised thing and everybody has to synch to it. No one generator
sets the pace. What happens is that as frequency drop more power is fed
into to fossil and hydro turbines to restore it. Because they run off
stored energy. But they are not themselves master clocks. The guts
running the grid are simply doing their job adding more power up to the
max when demand calls for it and easing back if the grid overspeeds.
Renewables can't do that.
Battery packs can BUT the peak power demands are very high which makes
for a very expensive set of batteries.
A summary of grid inertia that I found useful:
https://docs.nrel.gov/docs/fy20osti/73856.pdf
(Though it appears to have been written by "greens" so maybe not allowed here!)
On 08/05/2025 11:24, nib wrote:
A summary of grid inertia that I found useful:
https://docs.nrel.gov/docs/fy20osti/73856.pdf
(Though it appears to have been written by "greens" so maybe not
allowed here!)
I found it an interesting read. One of the conclusions was that to
maintain grid stability some solar/wind plants must be run at a level
below their maximum so that they can be called upon in an emergency.
Their maximum is of course not their theoretical maximum, but the
maximum they can produce with the wind/sun as it is at that moment.
I have a feeling that is not compatible with the contracts they have in
the UK, but I may be wrong there.
Andy
On 09/05/2025 00:22, The Natural Philosopher wrote:
You cant have many inverters dictating frequency. The Grid is one
synchronised thing and everybody has to synch to it. No one generator
sets the pace. What happens is that as frequency drop more power is
fed into to fossil and hydro turbines to restore it. Because they run
off stored energy. But they are not themselves master clocks. The guts
running the grid are simply doing their job adding more power up to
the max when demand calls for it and easing back if the grid overspeeds.
Renewables can't do that.
Battery packs can BUT the peak power demands are very high which makes
for a very expensive set of batteries.
Peak power output is exactly what battery packs are good for. Look at
the performance of a Tesla.
It's the long term output where they suffer. Keeping the grid running
through one of those dunkelflaute periods is the challenge that
batteries cannot meet.
Andy
On 09/05/2025 17:34, Vir Campestris wrote:
On 09/05/2025 00:22, The Natural Philosopher wrote:Well no, you risk a lot of damage if you flatten a battery in 9 seconds.
You cant have many inverters dictating frequency. The Grid is one
synchronised thing and everybody has to synch to it. No one generator
sets the pace. What happens is that as frequency drop more power is
fed into to fossil and hydro turbines to restore it. Because they run
off stored energy. But they are not themselves master clocks. The guts
running the grid are simply doing their job adding more power up to
the max when demand calls for it and easing back if the grid overspeeds. >>>
Renewables can't do that.
Battery packs can BUT the peak power demands are very high which makes
for a very expensive set of batteries.
Peak power output is exactly what battery packs are good for. Look at
the performance of a Tesla.
Which is the sort of toime period you need to replace spinning mass.
It's the long term output where they suffer. Keeping the grid runningWell of course they can, but as with grid stabilisation it needs to be massive and expensive.
through one of those dunkelflaute periods is the challenge that
batteries cannot meet.
On 09/05/2025 17:34, Vir Campestris wrote:
On 09/05/2025 00:22, The Natural Philosopher wrote:Well no, you risk a lot of damage if you flatten a battery in 9 seconds.
You cant have many inverters dictating frequency. The Grid is one
synchronised thing and everybody has to synch to it. No one generator
sets the pace. What happens is that as frequency drop more power is
fed into to fossil and hydro turbines to restore it. Because they run
off stored energy. But they are not themselves master clocks. The guts
running the grid are simply doing their job adding more power up to
the max when demand calls for it and easing back if the grid overspeeds. >>>
Renewables can't do that.
Battery packs can BUT the peak power demands are very high which makes
for a very expensive set of batteries.
Peak power output is exactly what battery packs are good for. Look at
the performance of a Tesla.
Which is the sort of toime period you need to replace spinning mass.
It's the long term output where they suffer. Keeping the grid runningWell of course they can, but as with grid stabilisation it needs to be >massive and expensive
through one of those dunkelflaute periods is the challenge that
batteries cannot meet.
Andy
In article <vvlof0$3113m$2@dont-email.me>, The Natural Philosopher <tnp@invalid.invalid> scribeth thus
On 09/05/2025 17:34, Vir Campestris wrote:
On 09/05/2025 00:22, The Natural Philosopher wrote:Well no, you risk a lot of damage if you flatten a battery in 9 seconds.
You cant have many inverters dictating frequency. The Grid is one
synchronised thing and everybody has to synch to it. No one generator
sets the pace. What happens is that as frequency drop more power is
fed into to fossil and hydro turbines to restore it. Because they run
off stored energy. But they are not themselves master clocks. The guts >>>> running the grid are simply doing their job adding more power up to
the max when demand calls for it and easing back if the grid overspeeds. >>>>
Renewables can't do that.
Battery packs can BUT the peak power demands are very high which makes >>>> for a very expensive set of batteries.
Peak power output is exactly what battery packs are good for. Look at
the performance of a Tesla.
Which is the sort of toime period you need to replace spinning mass.
It's the long term output where they suffer. Keeping the grid runningWell of course they can, but as with grid stabilisation it needs to be
through one of those dunkelflaute periods is the challenge that
batteries cannot meet.
massive and expensive
Andy
Just a question..
Is the "grid" as well linked as we seem to think it is or is it switched around depending on capacity of generation and load thereon. In
differing areas?.
Or..
Is a gas turbine spinning gas genset in say the far north of Scotland actually providing power here in say Cambridge?.
Is it linked to say another spinning mass gas genset in Cornwall?..
If you see what i mean..
Just a question..
Is the "grid" as well linked as we seem to think it is or is it switched >around depending on capacity of generation and load thereon. In
differing areas?.
Or..
Is a gas turbine spinning gas genset in say the far north of Scotland >actually providing power here in say Cambridge?.
Is it linked to say another spinning mass gas genset in Cornwall?..
If you see what i mean..
On Fri, 9 May 2025 23:13:34 +0100, tony sayer <tony@bancom.co.uk> wrote:
Just a question..
Is the "grid" as well linked as we seem to think it is or is it switched
around depending on capacity of generation and load thereon. In
differing areas?.
Or..
Is a gas turbine spinning gas genset in say the far north of Scotland
actually providing power here in say Cambridge?.
Is it linked to say another spinning mass gas genset in Cornwall?..
If you see what i mean..
I think an adequate analogy would be a sheet of heavy horizontal material, call
it a tabletop, supported by many legs. North Scotland is a leg, Cornwall is a leg. If Cornwall is low, ie not feeding enough power, the tabletop sinks.
If there are many legs, some will press up against the tabletop more, others will "hang" from the tabletop, dragging it down. This last is (or was) done: spin an unused generator by feeding from the grid. The only energy this uses is
friction and some resistive losses. The frequency drops: the tabletop moves closer to the floor -- the "leg" of the spinning generator now isn't hanging, but supporting the table. As the generator isn't hooked up to anything turning
it, it will start to slow: the leg isn't particularly solid, but squishy. But the inertia will keep the table supported for a bit, so like a battery that goes
flat quickly.
Also, this models the difficulty of lifting a tabletop off the floor if it has
collapsed, and some of the legs are unable to push until it is X off the ground.
Either push harder, or unload the tabletop, or break it up into smaller bits that can be lifted, ...
Thomas Prufer
On 08/05/2025 11:24, nib wrote:
A summary of grid inertia that I found useful:
https://docs.nrel.gov/docs/fy20osti/73856.pdf
(Though it appears to have been written by "greens" so maybe not allowed
here!)
I found it an interesting read. One of the conclusions was that to maintain grid stability some solar/wind plants must be run at a level below their maximum so that they can be called upon in an emergency.
Their maximum is of course not their theoretical maximum, but the maximum they can produce with the wind/sun as it is at that moment.
I have a feeling that is not compatible with the contracts they have in the UK, but I may be wrong there.
On Fri, 9 May 2025 23:13:34 +0100, tony sayer <tony@bancom.co.uk> wrote:
Just a question..
Is the "grid" as well linked as we seem to think it is or is it switched
around depending on capacity of generation and load thereon. In
differing areas?.
Or..
Is a gas turbine spinning gas genset in say the far north of Scotland
actually providing power here in say Cambridge?.
Is it linked to say another spinning mass gas genset in Cornwall?..
If you see what i mean..
I think an adequate analogy would be a sheet of heavy horizontal material, call
it a tabletop, supported by many legs. North Scotland is a leg, Cornwall is a leg. If Cornwall is low, ie not feeding enough power, the tabletop sinks.
If there are many legs, some will press up against the tabletop more, others will "hang" from the tabletop, dragging it down. This last is (or was) done: spin an unused generator by feeding from the grid. The only energy this uses is
friction and some resistive losses. The frequency drops: the tabletop moves closer to the floor -- the "leg" of the spinning generator now isn't hanging, but supporting the table. As the generator isn't hooked up to anything turning
it, it will start to slow: the leg isn't particularly solid, but squishy. But the inertia will keep the table supported for a bit, so like a battery that goes
flat quickly.
Also, this models the difficulty of lifting a tabletop off the floor if it has
collapsed, and some of the legs are unable to push until it is X off the ground.
Either push harder, or unload the tabletop, or break it up into smaller bits that can be lifted, ...
Thomas Prufer
Most of this massive thread is outside my technical knowledge but, I can >claim (so far) to be the only respondent who has actually started up a >generator and linked it to the local main supply!
Clywedog Dam West Wales, 1967 or thereabouts. 500kW hydraulic generator. >200ft. head available at the time. Juggling the initial flow allowed the >isolated generator output frequency to be matched with that of the mains >incomer. With the frequency matched and the isolator closed, more water
was allowed to flow through the generator creating power. Perhaps
briefly supplying Llanidloes, the local town.
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