Thank you for tackling these important and related topics!
It's always a struggle to explain the constraints on the physical grid. Too easy to be facile (and look like you're talking down to people) and too easy to go down a mathematical rabbit hole (where nobody wants to follow you).
Thank you, Kilovar 1959 for this informative article. I recall some of the mathematics I used during my undergraduate years at Harvey Mudd College in Claremont, CA. However, I graduated more than 50 years ago. I will reference your article in the notes to "Why is Grid Inertia Important?" at https://greennuke.substack.com/p/why-is-grid-inertia-important. I'm working on some follow-on articles. I will be discussing synchronous grid inertia in hydroelectric pumped storage plants and the conversion of DC to AC at the ends of DC interties. in upcoming articles at the GreenNUKE Substack.
Could you please edit the typography and lack of a space between the two words in your Substack? Note also that a megaVAR is a 1,000 times as large as a kiloVAR. VAR is an acronym for "Volt-Ampere Reactive." Google informs us that ....The unit of reactive power is Volt-Ampere-Reactive (VAR), which indicates the amount of electrical power required in a system for the formation of electromagnetic fields in inductive devices or to compensate for capacitive loads.
Gene if you're referring to forefront, that word appears in the Merrium Webster dictionary. Regarding Kilovar1959, that's my handle, it's not intended to be a correct electrical term. I have used that handle for 30 some years. Now regarding the correct format. The correct would be kiloVAr for kilo Volt Amps reactive, abriviated to kVAr. Next it would be Mega Volt Amps reactive, or MVAr. The M is capitalized. Small m = milli not Mega.
Kilovar 1959: My request is that you change Green Nuke to GreenNUKE. (I see where the confusion arose as a consequence of my lack of specificity. ) Thank you.
Rod thank you, but you wayvover estimate my mastery of math. 😆 Honesty that's engineer/ mathematician level calculations just because of all the inputs. I think Bonneville Power Agency (BPA) may be working on just that animal, it's takes some pretty significant computer power.
Thanks for your reply. From Gene Nelson’s linked earlier piece, and other tidbits I’ve gleaned, it’s not uncommon to find stories such as, “Australia went 5 days using only VRE!”
But when one digs further…there’s ALWAYS gas or coal turbines spinning somewhere on the system.
VRE proponents love to crow about batteries providing synthetic inertia.
But it seems likely to this layman that an awful lot of fire-prone storage would be required if that was the main way a grid or utility kept a system up and running.
Correct, I planned to circle back to renewables a little later, but you are on track. Check "The Electric Grandma" Substack for additional posts. The issue with synthetic inertia is one reaction time, because the logic has to recognize then respond to an event, and two the response is limited by the momentary capacity of the inverter and batteries. Electronics do not like overloads.
PS , I should point out that large rotating sychronous machines are allowed to be momentarily overloaded quite significantly by their protection. Those machines have a thermal damage curve based I-squared-T function. The protection will allow the overloaded as long as it does not approach the thermal damage curve. So during an event, these machines can put out a lot of energy in short bursts
I reference this ERCOT paper regarding the superior ability of nuclear power plants to supply synchronous grid inertia (SGI) in the notes to "Why is Grid Inertia Important?" See "Inertia: Basic Concepts and Impacts on the ERCOT Grid," April 4, 2018, Electric Reliability Council of Texas (ERCOT,) Austin, Texas, USA.
Fascinating article - thanks. I think you might be able to help me understand a topic that is somewhat closely related - "back EMF". If you have time, could you give a brief explanation? You have a way of making complicated things easy to understand.
Certainly, every conductor with AC current has a magnetic field that builds and collapses each half cycle. The change in that magnetic field is the same as moving a wire in a permanent magnetic field, it induces electricity into the wire. The negative is the induced current/voltage is in opposition to the primary current flow. That's why we call it back EMF. It's useful in a transformer where the back EMF limits current flow through the primary winding. When you put a load on the secondary winding it reduces the magnetic flux and increases the current flow in the primary winding.
Yes, thank you. My physics degree was earned over 50 years ago and I was fuzzy on some of the details. In my mind, I’ve been thinking that back EMF is a little like the law of diminishing returns. And I also liken it to the way the CO2phobes don’t seem to realize that for every wind or solar installation they put up, another gas power plant will be needed, which gives them net zero or close to it on their efforts’ effectiveness, even though that’s not the kind of net zero they say they want. Likewise, for every EV battery that gets built, lots of emissions and tons of earth were moved to mine the lithium. so I like the concept of back EMF as an analogy.
Thank you for tackling these important and related topics!
It's always a struggle to explain the constraints on the physical grid. Too easy to be facile (and look like you're talking down to people) and too easy to go down a mathematical rabbit hole (where nobody wants to follow you).
I enjoy reading your articles. Good job!
I think this covers it Meredith
https://substack.com/@whatarethechances/note/c-74297845?r=23kggy
Thank you, Kilovar 1959 for this informative article. I recall some of the mathematics I used during my undergraduate years at Harvey Mudd College in Claremont, CA. However, I graduated more than 50 years ago. I will reference your article in the notes to "Why is Grid Inertia Important?" at https://greennuke.substack.com/p/why-is-grid-inertia-important. I'm working on some follow-on articles. I will be discussing synchronous grid inertia in hydroelectric pumped storage plants and the conversion of DC to AC at the ends of DC interties. in upcoming articles at the GreenNUKE Substack.
Could you please edit the typography and lack of a space between the two words in your Substack? Note also that a megaVAR is a 1,000 times as large as a kiloVAR. VAR is an acronym for "Volt-Ampere Reactive." Google informs us that ....The unit of reactive power is Volt-Ampere-Reactive (VAR), which indicates the amount of electrical power required in a system for the formation of electromagnetic fields in inductive devices or to compensate for capacitive loads.
Gene, ?? Error in the text of the document, or the title to my Substack that's causing an ich?
Kilovar 1959: The error is in the first paragraph of your text.
Gene if you're referring to forefront, that word appears in the Merrium Webster dictionary. Regarding Kilovar1959, that's my handle, it's not intended to be a correct electrical term. I have used that handle for 30 some years. Now regarding the correct format. The correct would be kiloVAr for kilo Volt Amps reactive, abriviated to kVAr. Next it would be Mega Volt Amps reactive, or MVAr. The M is capitalized. Small m = milli not Mega.
Kilovar 1959: My request is that you change Green Nuke to GreenNUKE. (I see where the confusion arose as a consequence of my lack of specificity. ) Thank you.
Ahhhhh, my pleasure sir
Great read! Thank you!
Excellent piece! Will you be presenting a formula that a layman could use to determine how much inertia is required to keep a grid stable?
We often see something like, “Iowa produces half of all In-State electricity with wind power!”
But I have a feeling each individual utility in a particular state uses much less…
Rod thank you, but you wayvover estimate my mastery of math. 😆 Honesty that's engineer/ mathematician level calculations just because of all the inputs. I think Bonneville Power Agency (BPA) may be working on just that animal, it's takes some pretty significant computer power.
Thanks for your reply. From Gene Nelson’s linked earlier piece, and other tidbits I’ve gleaned, it’s not uncommon to find stories such as, “Australia went 5 days using only VRE!”
But when one digs further…there’s ALWAYS gas or coal turbines spinning somewhere on the system.
VRE proponents love to crow about batteries providing synthetic inertia.
But it seems likely to this layman that an awful lot of fire-prone storage would be required if that was the main way a grid or utility kept a system up and running.
Correct, I planned to circle back to renewables a little later, but you are on track. Check "The Electric Grandma" Substack for additional posts. The issue with synthetic inertia is one reaction time, because the logic has to recognize then respond to an event, and two the response is limited by the momentary capacity of the inverter and batteries. Electronics do not like overloads.
PS , I should point out that large rotating sychronous machines are allowed to be momentarily overloaded quite significantly by their protection. Those machines have a thermal damage curve based I-squared-T function. The protection will allow the overloaded as long as it does not approach the thermal damage curve. So during an event, these machines can put out a lot of energy in short bursts
I reference this ERCOT paper regarding the superior ability of nuclear power plants to supply synchronous grid inertia (SGI) in the notes to "Why is Grid Inertia Important?" See "Inertia: Basic Concepts and Impacts on the ERCOT Grid," April 4, 2018, Electric Reliability Council of Texas (ERCOT,) Austin, Texas, USA.
https://www.ercot.com/files/docs/2018/04/04/Inertia_Basic_Concepts_Impacts_On_ERCOT_v0.pdf I will be discussing the importance of SGI in upcoming articles at the GreenNUKE substack.
Thank you both, not only for this interesting discussion, but for all the time you both take to make such subjects understandable for the layperson.
I believe these inertial concepts will become much more important, and relevant, if Harris’ “Clean Power 2.0” ridiculousness is upheld.
I agree regarding your assessment of "Clean Power 2.0"
Fascinating article - thanks. I think you might be able to help me understand a topic that is somewhat closely related - "back EMF". If you have time, could you give a brief explanation? You have a way of making complicated things easy to understand.
Certainly, every conductor with AC current has a magnetic field that builds and collapses each half cycle. The change in that magnetic field is the same as moving a wire in a permanent magnetic field, it induces electricity into the wire. The negative is the induced current/voltage is in opposition to the primary current flow. That's why we call it back EMF. It's useful in a transformer where the back EMF limits current flow through the primary winding. When you put a load on the secondary winding it reduces the magnetic flux and increases the current flow in the primary winding.
Does that make sense?
Yes, thank you. My physics degree was earned over 50 years ago and I was fuzzy on some of the details. In my mind, I’ve been thinking that back EMF is a little like the law of diminishing returns. And I also liken it to the way the CO2phobes don’t seem to realize that for every wind or solar installation they put up, another gas power plant will be needed, which gives them net zero or close to it on their efforts’ effectiveness, even though that’s not the kind of net zero they say they want. Likewise, for every EV battery that gets built, lots of emissions and tons of earth were moved to mine the lithium. so I like the concept of back EMF as an analogy.
That's pretty good Al, I like that.
Thanks.