Huge increase in wholesale gas prices.

[adam2]

A generator is certainly worth considering if it enables a performance to go ahead rather than being cancelled.

Great care is needed to ensure EVERYTHING safety critical is connected to the generator. In particular make certain that the "mains" input to the emergency lighting is connected to the generator, this is often neglected, fire alarm ditto.

 

Edited October 6, 2022 by adam2

[Stuart91]

3 minutes ago, adam2 said:

Central battery emergency lighting in particular needs careful inspection so as to ensure that the correct lamps are fitted, clear or pearl lamps of the correct voltage and wattage, and lamps intended for illumination, not decorative lamps or pilot or indicator lamps. 

I was in a venue when all the power was cut, so that an electrician could wire in a temporary supply. In an 800-seat room, a phone torch would have been more use than the emergency lights. They did at least indicate where the exits were, but people would have been stumbling in the pitch dark to get to them. 

Then a few minutes later it died completely. The central battery seemingly hadn't been maintained since the building was constructed ~20 yrs earlier. 

[bruce]

I recently took part in a contingency planning exercise, with people from power companies, water and utilities, fire/police/ambulance, local and central government etc. 

One of the exercises was discussion on recovering from a complete widescale unplanned power outage - a "black start". The sort of thing that happened on US west coast a few years ago, where cascading trips took out tens of millions of consumers.

The "TL;DR" is that it takes much, much longer than you might think to put power back on, and there are lots of implications that may not be foreseen.

• If power is off, water pumping stations do not work. How long before your water stops? If you're on the top floor of a tower block, it might stop immediately.  How long before sewage starts spilling onto streets?
• How long will gas last for?
• What about comms - wired and mobile phones. After a few hours, none of it will work.
• Generators may be the answer in some cases, but will they be able to get diesel supplies? Who has priority - emergency services, or telcos, or hospitals?
• You can't buy fuel, cos petrol pumps don't work. In fact, you can't buy anything cos card payments fail.
• Electric vehicles cannot be charged. That's one reason that the electricity companies don't use EVs for their maintenance vehicles! Every Scottish Power Energy Networks main depot has a bowser with several thousand litres of diesel, and a hand pump.
• ... and the list goes on

 

[themadhippy]

Quote

. In fact, you can't buy anything cos card payments fail.

youll be able to buy a pint in my local micro pub,no cards accepted cash only and ale served straight from the barrel

[Stuart91]

1 minute ago, themadhippy said:

youll be able to buy a pint in my local micro pub,no cards accepted cash only and ale served straight from the barrel

Assuming that the ale hasn't frozen solid in the meantime. 

[bruce]

That sounds pretty good to me....

 

[J Pearce]

2 minutes ago, Stuart91 said:

Assuming that the ale hasn't frozen solid in the meantime. 

Freeze-distilled whisky.

Edited October 6, 2022 by J Pearce

[bruce]

1 hour ago, Stuart91 said:

Is there a point where it becomes prudent / justifiable to have a backup generator on hand?

A call centre near me has one sitting, I think it's been there since the building went up. Presumably someone did a risk assessment and figured that it was worth the spend, rather than lose the ability to service their customers. (As far as I'm aware there's nothing critical like a 999 switchboard in there)

Cost of generator + changeover circuitry + fuel, set against the losses of having to refund a full house? 

I'd say "probably not". 

Yes, you could keep your own local services running for a few hours in an entertainment venue. But when the punters get out, they're in dark streets. No mobile phone provision. No traffic lights. Very limited public transport - buses will continue, but train and tube will be off. Nowhere else open. 

[Stuart91]

10 minutes ago, bruce said:

But when the punters get out, they're in dark streets. No mobile phone provision. No traffic lights. Very limited public transport - buses will continue, but train and tube will be off. Nowhere else open. 

That would certainly be the case in a "dark start" scenario. But in a more controlled situation, I wonder how large the area of each "load group" is. It could be that normal service resumes a block or two away. (Also, are street lamps included in the load groups?)

What's potentially more worrying for venues, is punters being unwilling to buy tickets if they reckon there's a chance a blackout will derail their evening. (Whether it's a planned outage or unplanned)

[bruce]

Everything in the area is in the same load group, including street lamps- it's a geographic thing, determined by postcode, and I believe it's a fairly large area - at the megawatts level. Your load group is printed on your electricity bill. There should be some "online checkers", but all seem to be out of service at the moment.

The cynic in me says "this is all hype to get people to reduce usage"

 

 

[callumb]

57 minutes ago, themadhippy said:

no cards accepted cash only

Thats all very well but ATMs wont be working so no cash! 

[themadhippy]

Quote

Thats all very well but ATMs wont be working so no cash! 

you've obviously never heard the term "bar tab"

[adam2]

The geographical area covered by one load group varies a great deal so as to ensure that each load group contains about the same amount of load. In an urban area, an area still on will often be within walking distance. In a rural area the distances are much greater.

Street lights are in the same load group as other loads in the area.

It is unlikely that trains will run. The traction current for electric railways SHOULD STAY ON as it should have a dedicated high voltage grid connection and is a "protected load" not liable to rota power cuts. The lack of station lighting will prevent use during the hours of darkness. Lack of power for signals may close many lines. A limited service can be operated on some lines without any signalling.

Buses should still run, but beware creeping elfansafety that deems unlit streets to be too dangerous for buses. 

I recall the last lot of rota power cuts ! electric trains still operated then, with stations lit by oil lamps, but these days I doubt that the railway HAVE any oil lamps. 

Rota powercuts for three hours at a time will be most inconvenient but hardly a national disaster.

A national power failure, recovery from which requires a black start is far more serious. Most power stations require an external source of electricity to start up. A minority can "black start" generally from diesel engines that start from batteries or air bottles. 

There has never been a national black start in the UK. There WAS a regional black start after the great storm of 1987.

 

[adam2]

On 10/6/2022 at 9:16 AM, sleah said:

Seriously? They'll cut off hospitals 😮 I know they should have backup power but surely only for dire emergency?

Presume they are not of national importance. Apart of course for any where someone important is having treatment I bet!

Yes, hospitals will be cut off, if supplied by the local distribution system as most are. It must be repeatedly stressed that a planned or rota cut will affect EVERY consumer in the area cut off. There is simply no way to leave selected customers on.

Hospitals have standby generators some of which will work when called upon. Very few hospitals have 100% backup power. A common approach is about 25% of the lighting and about 25% of the socket outlets, with 1005 backup only for ICUs and operating theatres.

It is an NHS policy that pre planned major surgical operations must not be started unless TWO electrical supplies are available such as mains and a backup generator. Therefore if the mains supply is already off no planned surgery may be started. Unless duplicated generators are available.

Minor surgery may be performed with an assistant holding a torch.

[richardash1981]

After digging out the National Grid Winter Outlook, the striking thing to me is that we are 3.4GW short - after firing up the retained coal plants (only 2GW!), the plan requires 1.4GW from Norway and 2GW of planned load reduction in order to balance the grid at peak, assuming uninterrupted gas supplies. These 3.4GW would hopefully be imported from Europe, but only the 1.4GW from Norway is relied upon, hence the need for additional gap closing.

Octopus are getting behind the idea of paying customers to switch off at peak times, which will help with generating capacity (mostly what the Winter Outlook focuses on) but not necessarily with total consumption (which matters more in a gas supply crisis). https://www.bbc.co.uk/news/business-63175030. Note this is new and will not "launch" until 1st November ...

If anyone is interested, there is a 2014 briefing on Rota Disconnection from Manweb here: https://www.merseysideprepared.org.uk/media/1241/briefing-paper-rota-load-and-black-start.pdf (no date, but the reference to Supplemental Balancing Reserve dates it) . This references the Electricty Supply Emergency Code which is here: https://www.gov.uk/government/publications/electricity-supply-emergency-code.

In response to @adam2 I have to note that where larger hospitals are supplied at HV* they do qualify for Protected Site status (ESEC section 5.2 / Table 1) and so network operators will make best efforts to not disconnect them, but also that a proportionate load reduction is expected from these sites (but they are left to decide when and how to make it).
* In urban areas, typically dedicated, N-1 redundant, 11kV feeders direct from busbars at 33kV Primary site.

The inclusion of "Financial services where there is a national need for continued operation" in that list will raise some questions about whether data centres used for high frequency trading should be shed first ...