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Mar 10·edited Mar 11Author

Here's a relevant new Substack post from David Turver at Eigen Values: Offshore Wind: Follow the Money - UK billpayers subsidising overseas investors and getting expensive, unreliable energy in return by David Turver, March 9, 2024.

https://davidturver.substack.com/p/offshore-wind-follow-the-money

While U.K. centric, this article will help you to understand why the economic elites advocating for fickle offshore wind oppose safe, reliable, abundant, cost-effective and zero - emission nuclear power, such as that produced at Diablo Canyon Power Plant.

For some historical context, here's an article from a dozen years ago that is spot on today:

Broken down and rusting, is this the future of Britain's 'wind rush'?

By Tom Leonard, Published 21:00 EDT, 18 March 2012, The Daily Mail (U.K.)

https://www.dailymail.co.uk/news/article-2116877/Is-future-Britains-wind-rush.html

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Here's a post by Robert Bryce that is complementary to several themes I wrote about in this article. https://robertbryce.substack.com/p/these-10-charts-caused-an-ngo-hissy My next article will cover how hydroelectric pumped storage is being used for grid frequency stabilization instead of bulk energy storage.

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Mar 13Liked by Gene Nelson, Ph.D.

Good one Gene,

There is a fundamental lack of understanding of the technical electrical power engineering theory and practice and how inductive and capacitative supply and loads on an electrical system.

The system is designed around synchronous generation which is inductive and renewables are capacitative on my understanding.

I'm not an electrical engineer, I was a Reactor Physicist and latterly an Operations Engineer for over 20 years, and a lot of people just think its power in and out.

They have no idea of the potential problems of large amounts of intermittent non synchronous generation might have on the reliability of a power grid system.

Thanks for attempting it! beyond my engineering skills!

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Thank you. I agree the AC power grid has been designed around synchronous generation. Please note my comments posted on March 13, 2024 above which outline the "TGFI problem."

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Thanks for this excellent write-up on this subject. A question occurred to me while reading - shouldn't it be possible to outfit inverters with a feedback circuit that tracks the instantaneous grid frequency and continously adjusts the output frequency to match it?

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The challenge is the massive amount of energy storage that would be required at each inverter based resource to achieve this frequency control (as well as the robust electronics required to handle the large instantaneous power requirements.) This is akin to the theoretical grid forming inverters (TGFI) mentioned in the article. Given that TGFIs are not yet available, I believe the best approach is to use synchronous grid inertia, as has been the case since about 1895. https://edisontechcenter.org/AC-PowerHistory.html

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Ah, gotcha. Thanks for pointing that out to me.

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Very informative read! Thank you for going over this critical topic.

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A very informative 2018 technical article regarding the importance of synchronous grid inertia [SGI] from the Electric Reliability Council of Texas (ERCOT) is "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

This article underscores that nuclear power plants (like DCPP) provide the largest amount of SGI. The article notes neither solar nor wind provide significant amounts of SGI. Since ERCOT has negligible interconnection to any other U.S. power grids, their grid functions effectively as the power grid on an island. ERCOT established a minimum SGI constraint they call "Critical Inertia;," described in section 6 of this report. Since ERCOT is a large system, the value of Critical Inertia is also large. To ERCOT's credit, their real-time system dashboard shows the amount of inertia available to ERCOT. CAISO needs to supply real-time inertia information on their website. "Inertia" appears 34 times using the CAISO website search tool.

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Here''s some additional information regarding grid inertia. (However, I disagree with the author's claim that wind power is capable of providing significant amounts of synchronous grid inertia. This glossary provides definitions for the acronyms included below.)

Glossary of Electric and Gas Industry Terms and Concepts - Indiana Utility Regulatory Commission, Updated and Revised February, 2022

https://pubs.naruc.org/pub/DD7DB67E-1866-DAAC-99FB-36526B06C7C6

Inertia – as Voltage Support (see also Automatic Generation Control - AGC, Area Control Error (ACE), Frequency, and Kinetic Energy): Baseload coal and nuclear generators, like natural gas generators other rotating machines (motors and generators) including wind turbines provide needed inertia to support frequency throughout an entire electric interconnection. At the instant load changes, the system must change generation to match so power into the system must equal power out. Since it is not feasible to change the fuel output or steam input of the generators on a split second basis, the rotating kinetic energy of every machine in the entire interconnection serves to help balance the system. For example, when a light is turned on, the energy needed comes from kinetic energy and the machines slow down and frequency drops. For a single light switch the drop in frequency is imperceptible. However, a rolling mill at a steel plant may cause a perceptible change. The Automatic Generation Control (AGC) system, on most large generating units, almost instantaneously recognizes the Area Control Error (ACE), which is a combination of the frequency drop and the importation of power from the rest of the interconnection as energy is supplied by their machines, and adjusts the output setting of the generators to restore frequency and tie-line flow. Thus, every piece of rotating equipment supplies inertia, including wind turbines (but not solar panels). Of course, large steam-powered turbines have considerably more inertia than a wind turbine (unless there are a few hundred of them) and wind turbines generally do not have the automatic generation control aspect of being able to react to the area control error.

Inertial Response: This is the kinetic energy stored in the rotating mass of all of the synchronized turbine generators and motors on the interconnection. Produced by the slowing of the spinning inertial mass of rotating equipment on the interconnection that both releases the stored kinetic energy and arrests the decline of the interconnection frequency. This happens immediately following a disturbance.

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Nukes as all base load plants require off site power or emergency generators to keep the plant auxiliary equipment running when in startup or offline. Auxiliary systems are for example Coolant pumps to name one, but hundreds of other systems require vital power, both AC and DC. When a plant trips and goes offline the party is over. But an off line plant is not the same as an “Islanded Plant” requiring Black Start Power. Few understand the mechanics of elecric power generation let alone the transmission system and “Grid”. Last of all are the political hacks who are responsible for the mess they have created with a “Green Grid”. It takes a lifetime in the Industry to understand the dynamics of the Electric Power System. And no one knows it all.

My first month working in a 1200 MW plant I asked my Mentor where is the master frequency source for plants to sync to should the entire grid collapse. He said thats a good question son, and its a complicated answer. That began my long career in the Power Generation Industry. And I retired knowing that answer. Its too complicated for details here, but somewhere there will be a 60hz voltage available to synchronize to, even if it comes from a single Black Start plant that is islanded and becomes the master frequency generator at 60.8 hz for the next plant to sync to. Its a delicate dance to add loads and maintain frequency and voltage in increments as more plants are paralleled together. Sometimes it takes many tries at getting it right. Its so rare an event that few ever get to put into play what they think they know. The inertia of multiple rotating generators together adds stability as more loads and generators are added. And thats why what the Author of the Blog is telling is so terribly important. To my knowledge there are no Inverter based Black Start plants and for good reason. No rotational inertia.

And I ask are the Grid Modeling tools in use today good enough ? I dont know. My life in the industry was in Plant O&M. We had to make work what the Master Wizard Inventor Tesla gave us. We are literally back to the differences and shortcommings of Edisons DC system vs the Polyphase creations of Tesla.

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author

Thank you for your confirmation of the importance of synchronous grid inertial.

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Gene, are there any real and significant black start issues with the grid that has a high percentage of renewals?

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"Black start" cap;ability is not added via increasing amounts of solar or wind. With appropriate use of FLEX equipment in conjunction with the plant's emergency diesel generators, I believe that a nuclear power plant could "black start" (i.e. start up despite a region-wide blackout.) Here are a few more details from a 2014 article: https://www.power-technology.com/features/featureblack-start-how-do-you-restart-a-nuclear-power-station-when-the-grid-goes-off-4176366/

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Very good article on grid inertia. I am an electrical engineer that worked at Diablo Canyon Power Plant for 36 years. I appreciate your articles advocating for nuclear power. Just wanted to say. Your value for amperage on a Diablo Canyon generator is inaccurate. The rating is much closer to 30,000 A, I don’t remember the exact number. The MVA rating is approximately 1300.

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Thank you for your feedback and appreciation. Your reply regarding the DCPP amperage prior to step-up to 500 kV is puzzling. The product of primary voltage times amps is 1,300,000,000 for each unit. Primary voltage is 25,000 Volts. Dividing MVA by 25K yields 52,000 Amps. I'm using RMS values with the approximation that 3-phase AC power is equal to DC power.

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You need to multiply by the square root of 3 to calculate 3 phase power.

25,000 x 30,000 x 1.73 = 1298 MVA

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I understand! My approximation was incorrect. Thank you for the clarification. The disadvantage of three-phase power is that it requires three conductors, not two required for direct current. However, almost all AC power is three-phase power. The factor of 1.73 shows why. (The Pacific Intertie, which is 1 million Volts DC requires large earth return grounds connected to the Celilo and Sylmar Converter Stations. In a properly-balanced 3-phase system, there is very little alternating current moving through the fourth neutral wire.) When the 25 kV is stepped up to 500 kV, the turns ratio is 20:1, which reduces the current 20-fold, down to 1,500 Amps. Since the power dissipated in a transmission line is proportional to the square of the current, stepping up the voltage to 500 kV reduces the power loss to 1/400 of the value at 25 kV. )

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Thanks for explaining this!

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You are welcome!

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Looks like technology has caught up with the issue of IBRs providing ancillary services. Grid forming inverters (GFM) are now available and are providing grid inertia for grid frequency stabilization. These new inverters can also provide black start capability. They are successfully being used in a small grid in Kauai. A large grid like ERCOT is working towards adding more GFMs.

NERC issued a standard for them in 2023, “GFM specs for Battery Systems” BESS

https://www.nrel.gov/docs/fy24osti/90256.pdf

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Oct 2·edited Oct 2Author

Thank you for the new reference. Per https://www.kiuc.coop/generation-portfolio, their Tesla BESS system is rated at 13 MW for 4 hours. It is a tiny start, but a far cry from DCPP, which is rated at 2,256 MW and runs for about 13,500 hours between refueling outages. The link I provided shows that the KIUC generation fleet is mostly fossil-fired instead of solar. This makes sense as the solar generation runs only about 25% of the time. Solar plus batteries would not be a cost-effective power grid for Kauai.

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Ben Heard et al wrote about this in "Burden of proof: A comprehensive review of the feasibility of 100% renewable-electricity systems." Renewable and Sustainable Energy Reviews, 76:1122–1133, September 2017. https://www.sciencedirect.com/science/article/pii/S1364032117304495. Thanks for the additional details and deeper explanation.

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You are welcome. Ben Heard's 2017 article reveals the "Achilles Heel" of solar and wind - their inability to provide meaningful contributions to ancillary services which maintain grid stability. His paper mentions "ancillary" 21 times. "Frequency" is mentioned 14 times. As I study this problem more, I conclude the purpose of solar and wind is a delaying tactic by fossil fuel interests that refuse to acknowledge the wise counsel of the expert scientists and engineers of the California Council of Science and Technology who were requested by the California Energy Commission in 2011 to develop a plan to cost-effectively decarbonize the California electric power grid. Their answer was to emulate France or Sweden and build about 30 new nuclear power plants. https://tinyurl.com/CCST-Nuclear-1

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Thank you also for this (read and saved it). Was really glad to read Gene's post on grid inertia because, as a non-expert supporter of "green" 'n clean nuclear power, my first read on the critical role of inertia was via the Oxford Energy Institute (https://www.oxfordenergy.org/wpcms/wp-content/uploads/2023/09/Insight-135-Meeting-the-Challenge-of-Reliability-on-Todays-Electricity-Grids.pdf) so I read more by Staffan Qvist (and will keep an eye out for co-authors Mohammad Al Hammadi , David G. Victor's). This was before I found Gene Nelson's Substack and site, which I also greatly appreciate!

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Thank you Daph for your endorsement and informative link from 2023.

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Would it be correct to say that inverter-based resources not having their own frequency means that the inverter has to follow the existing phase and try to match that - but if there isn't a sufficiently large base of sources with an intrisnic phase, they don't have a signal to follow?

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I believe there is an adequate signal to follow. Again, the problem for IBRs and TGFIs is the lack of energy storage and electronics capable of handling large instantaneous power flows. That is the strength of large synchronous generators such as Diablo Canyon Power Plant. Over a million pounds rotating at 1800 RPM is beneficial. The next installment will be discussing pumped hydroelectric storage units. PG&E designed Diablo Canyon in conjunction with Helms Pumped Storage whose three motor-generators rotors rated at 404 MW weigh a million pounds each. See: https://web.archive.org/web/20160104221648/http://www.pgecurrents.com/2015/12/16/helms-pumped-storage-facility-team-safely-successfully-completes-unit-1-planned-outage/

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Mar 14Liked by Gene Nelson, Ph.D.

I'll be looking forward to that. With no education in energy, I've got a lot of catching up to do if I want to translate this stuff for my fellow laymen.

From another read of the article, my understanding of the problem is more that IBRs and TGFIs cannot dump large amounts of electricity on the grid immediately to restore frequency in event of a fault - very fast reactions is something only really available with pumped hydro from my reading.

Let me know where I've gone wrong - as one usually does when new to a field. :)

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Your analysis regarding the instantaneous provision of energy (or the absorption of energy) applies to all synchronous generators such as DCPP, not just pumped storage.

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Is the issue a lack of suitable electronics, rather than something with the generation? And the inertia inherent in massive flywheels being able to resist such changes physically rather than compensate for them with electrical output?

This is where I'm at with the Guides, by the way:

https://argomend.substack.com/p/the-laymans-guide-to-electricity

https://argomend.substack.com/p/the-laymans-guide-to-electricity-bde

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Jul 2·edited Jul 2Author

The key concept is that a generator is a machine that can instantaneously convert rotational kinetic energy into electricity and vice versa, as you mention in one of your guides. I will be discussing the use of "spin" in hydroelectric pumped storage plants in an upcoming GreenNUKE article. At plants such as Helms Pumped Storage, east of Fresno, California, the plant simultaneously pumps and generates to create "spin" to help stabilize voltage and frequency on the grid. Each of the three pump-generator systems have rotating components weighing a million pounds per system. With so much solar and wind on the California power grid, this grid stabilization is more important than bulk energy storage.

I've offered some comments to some of your informative guides regarding electricity. I count four guides as of 01 July 2024. Keep them coming!

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