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Domestic mains voltage and frequency
Domestic mains voltage and frequency
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Old 13th August 2019, 03:41 PM   #171
BeanAnimal is offline BeanAnimal  United States
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Originally Posted by DF96 View Post
The sort of energy-intensive industry which can cope with controlled load shedding cannot cope with the cost of green electricity so has mainly moved elsewhere.
And the industry that CAN NOT cope - has also moved.

You can't allow a rolling blackout or load shed event to shut down an arc furnace, ladle or extrusion mill. Damages can easily be in the tens of millions and/or cause fatal catastrophic events.

You can't allow a rolling blackout or load shed event to shut down the ventilation fans, conveyors, long walls, etc, at a coal mine. Again the damages can easily be in the millions of dollars and/or cause fatal catastrophic events.

On the flip side - It is my understanding that historically, the demand of arc furnaces and their production schedules, are what have in-fact prompted rolling blackouts to ensure that the furnaces do not go down. This was when there were no codified "green energy" quotas or artificial limits on energy production.

With each passing day, as we remove the ability to scale to demand in real-time, we put more stress on the stability of the system and users of that system.
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Old 13th August 2019, 04:44 PM   #172
mondogenerator is offline mondogenerator  England
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^This is true of course.

In days past, not all that long ago (I'm 40) large hubs of industry had provision for on site generation, certainly in the rotating machine industry (and perhaps others, as I speak of only my experience).

Those provisions kept the factories running, and in times of slack, and increased grid demand these were spun up to supply instead. OK so it isnt rapid response to demands, but a small leveller. But industry has seemed to abandon such assets, preferring instead to blame it on weakness in state infrastructure, during times where the state has retreated into hiding and also seems to shun responsibility (privatisation).

Sadly the populace still bears the brunt, and industry make money regardless, while seeking to avoid all costs in maintaining the infrastructure it needs to exist.

I've been saying for years to my friends that there is already no need for regional warfare, the wars are already fought won and lost, by business. And we, countries, governments, society are just dragged along for the ride. We are all just assets to be used by industry, coerced/brainwashed to earn, spend, consume, die, leaving as little of our accumulated wealth to those we wish, as possible. The end has already begun.

Now time for some Vengaboys and to dance like a 5 year old, and forget everything I just wrote
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Last edited by mondogenerator; 13th August 2019 at 04:47 PM.
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Old 13th August 2019, 05:37 PM   #173
BeanAnimal is offline BeanAnimal  United States
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Originally Posted by mondogenerator View Post
^This is true of course.

In days past, not all that long ago (I'm 40) large hubs of industry had provision for on site generation, certainly in the rotating machine industry (and perhaps others, as I speak of only my experience).
Correct - those are the industries that could (at some cost) prepare for outage - by on-site prime power generators. The rub (mentioned above) is that the cost of the mandated "green" energy that they consume during peak times is too expensive for them to remain in business.

Ignoring labor cost itself - Why would a factory operate in a State or Country where the price of energy is artificially inflated both by the forced use of expensive sources, forced "carbon credit offset" purchase and the artificially imposed limited supply caused by the forced idling of cost effective sources? -- Especially if some other State or Country offered cheap, unlimited power without said artificial supply limits, carbon credits and inflated "green" prices.

As far as the mining and steel industry - you can't put enough backup or prime power on-site to supply their needs. A steel mill uses as much power as a small town - and as much as a small city (60 MVA) when the arc furnace is running. Ever see a 150 MWh generator? It is called a power plant

Somewhat related - It was not that long ago that power houses were built like roman monuments, for they were the heart that kept a modern city running. Their architecture was something to behold, though most of it was never meant for public consumption, but rather an ode to the significance of its very own existence.

This is one book with some examples from one city: I HIGHLY suggest buying it if you are at all into architecture, industrial revolution, engineering or any related subject. There are other books about and examples from cities all over the world.

"Palazzos of Power"

Palazzos of Power: Central Stations of the Philadelphia Electric Company, 1900-1930: Aaron V. Wunsch, Joseph E. B. Elliott, Joseph E. B. Elliott, David E. Nye: 9781616895006: Amazon.com: Books
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Old 13th August 2019, 06:54 PM   #174
Galu is offline Galu  Scotland
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Originally Posted by DF96 View Post
Why did some users (e.g. railways) take so long to recover after the power was restored?
Teething problems with new technology perhaps?

It was the new class 700 and class 717 trains which had to be restarted by technicians.

The class 717 was phased-in to regular service as recently as March 2019 (although the class 700 has been operating since 2016).

A 'safety feature' is said to be responsible for shutting down the trains.
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Old 13th August 2019, 07:06 PM   #175
BeanAnimal is offline BeanAnimal  United States
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Teething problems with new technology perhaps?

It was the new class 700 and class 717 trains which had to be restarted by technicians.

The class 717 was phased-in to regular service as recently as March 2019 (although the class 700 has been operating since 2016).

A 'safety feature' is said to be responsible for shutting down the trains.
We have a Tesla - some really cool things about it - but I can't get over the fact that it has to be "rebooted" to solve oddball issues or partial system malfunctions that occur from time to time (some of them apparently unintended side effects of safety routines....) Maybe the train needs a CTRL+ALT+DEL keyset?
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Old 13th August 2019, 07:53 PM   #176
mondogenerator is offline mondogenerator  England
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Ever see a 150 MWh generator? It is called a power plant
FWIW i work in, operate and maintain, a mini power plant.

I reckon Youd get 150MVA genset in perhaps a 150ft long shop, so perhaps not really an issue for some industries at all (steel/foundry), but mining is a different story perhaps?

We have about 40MVA of synchronisable 50Hz load, used as product testing supplies, driven by a max grid load of 3MW.

I dont pretend to understand the whole picture, far from it, but I really dont know why there arent more power stations just running spinning reserve in the form of synch motor driving alternator, or flywheel, as grid stabilizers.
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Old 13th August 2019, 08:24 PM   #177
BeanAnimal is offline BeanAnimal  United States
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Originally Posted by mondogenerator View Post
FWIW i work in, operate and maintain, a mini power plant.

I reckon Youd get 150MVA genset in perhaps a 150ft long shop, so perhaps not really an issue for some industries at all (steel/foundry), but mining is a different story perhaps?

We have about 40MVA of synchronisable 50Hz load, used as product testing supplies, driven by a max grid load of 3MW.

I dont pretend to understand the whole picture, far from it, but I really dont know why there arent more power stations just running spinning reserve in the form of synch motor driving alternator.
40 MVA is nothing to sneeze at - you have your own sub station

For a while the natural gas co-gen plants were a big thing. Issue is now - Just a huge internal combustion engine and genset running of natural gas. I have seen a few at college campuses, hospitals, etc.
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Old 13th August 2019, 08:30 PM   #178
BeanAnimal is offline BeanAnimal  United States
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Also excuse my units above... Before anybody corrects me... I do know the difference between MW and MWh - just happy typing along with fingers faster than the brain is...
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Old 13th August 2019, 08:46 PM   #179
MarcelvdG is offline MarcelvdG  Netherlands
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Originally Posted by Gnobuddy View Post
In other words, the LADWP's energy-efficient home is allowed to use up about as much energy as nearly twelve servants working inhumanly long and hard hours every day. The small and energy-efficient home consumes an order of magnitude more energy than one of our pre-industrial ancestors did.
As far as I know, our pre-industrial ancestors used biomass, particularly wood, rather than slaves to heat their homes.

By the way, the reports of the IPCC can all be downloaded from ipcc.ch. They claim that there are still pathways that either limit the global warming averaged over the Earth's surface to below 1.5 K, or manage to get it below 1.5 K after a small overshoot, although it is getting more and more difficult with each passing year. The reports are so long and written in such a tedious style that I never managed to read one, though.
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Old 13th August 2019, 09:32 PM   #180
martin clark is offline martin clark  Europe
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Originally Posted by BeanAnimal View Post
For a while the natural gas co-gen plants were a big thing. Issue is now - Just a huge internal combustion engine and genset running of natural gas. I have seen a few at college campuses, hospitals, etc.

For primary generation off fossil fuels, natural gas co-gen plants (combined cycle gas turbines) remain the best & most efficient - by no small measure.

The internal-combustion prime-mover type are usually used as combined heat & power to serve a campus or similar, and offer cost efficiencies - when the hot water thermal output plus electrical output, is cheaper (and also rather more carbon-efficient) than delivering that total demand off grid supply electricity (and gas), in essence.

Such CHP units are also usu. two orders of magnitude at least smaller than typical CCGT sites, and then only make sense if the end-user can make use of all of the waste heat, almost all of the time - such to provide domestic hot water or equiv space heat demand via a campus primary hot water main ('district heating' is a common term). Yes, such things suit primary healthcare and certain Uni (and other) campus uses well; in those contexts I've used them even right down to the 25-50Kw [electrical+heat] output range. But it's not a grid-replacement solution: just an efficient answer when the scale and scope and load demand can be very-well-defined, and modelled; and relatively small-scale in demand - up to a MW or two or so.

Last edited by martin clark; 13th August 2019 at 09:35 PM.
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