Huge increase in wholesale gas prices.

[Paul TC]

Th IET magazine published an article that suggested "black start" of the UK supply from total failure would take several days and longer if it failed first time.

[bruce]

14 minutes ago, Paul TC said:

Th IET magazine published an article that suggested "black start" of the UK supply from total failure would take several days and longer if it failed first time.

Easily.

To maintain synchronisation, they need to Start with once central distribution point, then "grow outwards". Figure I heard of was 4-5 days to do Central Scotland.  

ironically, north of Scotland, although much bigger, would be quicker, since more Hydro.

[adam2]

On 10/6/2022 at 8:52 PM, bruce said:

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

 

Water supply------Varies, some places have gravity supply from elevated reservoirs and should be OK for days. Others are reliant on pumps at the waterworks, these should have backup power, but reliability is unknown. In tower blocks yes it would go off very quickly.

Sewage-------Probably OK in MOST places as it flows by gravity to the sewage works, if power is not available for treatment there is generally an emergency overflow to a watercourse or into the sea. Not ideal but better than flooding the streets .In some very low lying districts gravity flow is not possible, the waste then flows into a pit or cavern under the road, from whence it is pumped electrically to the sewage works. The pit or cavern will take many hours to fill up, so no problem for a three hour rota cut, but if it was off longer term, yes flood of sewage. 

Comms------Traditional copper wire telephone lines should be fine as the exchanges have large batteries for exactly this eventuality. However as discussed elsewhere there is growing reliance on fibre optic and internet based telephone service this is very vulnerable. Cellphones are vulnerable to loss of power to the masts, MIGHT be ok in an urban area by connecting to a mast that still has power.

Generators-------------Could be most valuable, but run time is limited to the fuel STORED ON SITE do not count on any resupply in a prolonged outage. In the case of rota power cuts, then re-supply should be simple between the cuts. If possible for say a theatre, store enough fuel for 10 hours operation. 3 power cuts each of 3 hours, plus a margin. That should last a week, remembering that some cuts will be when you are not open. Rule of thumb is to allow one litre of diesel for every 3 kwh. So to run a 100 kw generator for 10 hours that is 1,000 kwh or about 333 litres of diesel fuel. You might well get 4 kwh per litre, but do not count on this. 

Vehicle fuel wont be available without power at the filling stations. No problem for 3 hour rota power cuts, simply fill up before or after the 3 hour power cut, or in an area that has power. Could be serious in a prolonged outage. Keep your vehicle tank at least half full, store spare fuel if you can safely.

Electric vehicles should also be fine in 3 hour rota cuts, They should charge just fine between the cuts. A serious problem though in the event of a long term failure.

Natural gas supplies----------Should be fine. Natural gas pumping stations are either "protected loads" not liable to rota power cuts, OR use gas turbine pumps.  

[Andrew C]

On 10/8/2022 at 8:36 PM, adam2 said:

Sewage-------Probably OK in MOST places as it flows by gravity to the sewage works, if power is not available for treatment there is generally an emergency overflow to a watercourse or into the sea.

 

I could make a comment on "emergency" being a day when the share price seems to be dipping - but I'd have to moderate myself.

[sandall]

On 10/6/2022 at 3:14 PM, adam2 said:

........ small chargers intended for sealed lead acid batteries are widely available on fleabay.

Good call, thanks. An el-cheapo once has just landed on the doormat.

[adam2]

The natural gas price has moderated somewhat, but before any undue optimism breaks out, note the following.

The present price is about 100 pence a therm, between two and three times the historical norm of about 40 pence a therm.

Prices are expected to increase in Autumn and Winter.

An industrial dispute appears likely in an Australian LNG plant. Any such dispute will tend to restrict supplies and increase prices.

I again urge that urgent consideration be given to ensuring that gas and electricity are used wisely and that waste is avoided.

Energy efficiency should be carefully considered when purchasing replacement or additional equipment.

[adam2]

On 10/7/2022 at 9:09 PM, Paul TC said:

Th IET magazine published an article that suggested "black start" of the UK supply from total failure would take several days and longer if it failed first time.

There has never been a UK wide black start, so we do not know how long it would take, but several days is plausible.

There HAS been a regional black start in London and the south east immediately after the great storm of 1987, that took only a few hours. 

Coal burning power plants can take up to 24 hours to black start from "cold and dark", but much quicker if they were running before the emergency and then tripped to "house load only".

These days we have little coal burning capacity, and black start facilities are provided by gas turbine power stations and by hydroelectric stations. International interconnectors are of no direct use for black starting as they are DC and the inverters used wont feed into a dead system. Once limited grid supplies are available then interconnectors could help.

The pumped storage schemes at Dinorwick in Wales and at Cruachan in Scotland are important black start facilities.

The national grid have particular requirements for black start power stations, including the ability to make at least three attempts at black starting in case the grid trips during the first attempts, and sufficient fuel (usually light oil) stored on site for 72 hours operation. And the ability to handle sudden changes in load.

During a black start emergency the grid frequency may vary between 52 cycles and 47.5 cycles, and down to 47 cycles briefly, a much larger range than allowed under normal conditions.

 

The present concerns over the price and availability of natural gas are most unlikely to lead to a complete blackout, Rota power cuts certainly, but a complete outage no way !

[richardash1981]

22 hours ago, adam2 said:

There has never been a UK wide black start, so we do not know how long it would take, but several days is plausible.

The present concerns over the price and availability of natural gas are most unlikely to lead to a complete blackout, Rota power cuts certainly, but a complete outage no way !

"Plausible" meaning that it's a scenario the industry actively designs and plans for, the main restriction being the number of suitably qualified staff available on the ground to operate the large amount of non-automated equipment and process required.

Completely agree that there are many systems to avoid ever getting that far, and they work - 9th August 2019 being an example of those systems working to keep the majority of the network alive, albeit with some very high profile disruption. The most likely risk during a period of shortage of supply is probably not event rota disconnection (which deals with longer term, predicted shortage), but a repeat of a 2019-like event - a short term glitch somewhere triggering substantial automated load shedding to ensure the system as a whole survives. Those with longer memories will know that one occurred in 2009 as well ... (both cases caused by technical defects in plant, not a fuel shortage).

[adam2]

And in Scotland a new and very large pumped storage power station has been approved, with an output of 1,500 MW and able to maintain that output for about 20 hours.

That will help a lot in the event of a black start. Controls, instruments and emergency lighting would need power, but the modest demand is easy to supply from batteries or a diesel generator.

https://www.sse.com/news-and-views/2023/03/britain-s-largest-pumped-hydro-scheme-in-40-years-gets-100m-investment-boost/