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Coming shortage of UK generating capacity?
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vtsnowedin



Joined: 07 Jan 2011
Posts: 5360
Location: New England ,Chelsea Vermont

PostPosted: Tue Oct 11, 2016 1:28 am    Post subject: Reply with quote

adam2 wrote:
Tonight's figures for generation look interesting WRT the coming winter.

Wind, nuclear, coal fired electricity, and hydro/pumped storage production are all within the expected range, 1.4, 7.3, 5.2, and 2.5 respectively.

Indicated demand is about 38.

CCGT is over 22.

On a cold winter evening, indicated demand is likely to reach about 53, or about 15 more than tonight.

Diesel and OCGT could probably contribute 1, and coal about another 4, so that leaves another 10 needed, presumably from CCGT.
Do we have another 10 of CCGT ? for a total of 32 ? not so far as I am aware.
However TPTB seem very relaxed and at least fairly confident that all will be well.

BTW, the French interconnector is broken again, so that has lost 1.5, but it might be still/again broken in the winter peak.

All figures are in GW.

Imagine the stress level of those poor souls that manage your grid. The people that actually flip the switches, not those that live in a board room.
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PS_RalphW



Joined: 24 Nov 2005
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PostPosted: Tue Oct 11, 2016 12:25 pm    Post subject: Reply with quote

https://www.theguardian.com/environment/2016/oct/11/energy-first-as-uk-successfully-transmits-data-via-national-electricity-grid

prototype demand control system on the national grid. Looks like a lot better use of
money than smart metres.
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adam2
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PostPosted: Tue Oct 11, 2016 1:19 pm    Post subject: Reply with quote

Certainly an interesting idea, but wont help for this winter.

Short term demand control can certainly help during the "high peak" of the worst 15 or 20 minutes. Or at any time in the event of any sudden shortage of generating capacity.

It must be remembered that such schemes do not save energy, they postpone the consumption until a more favourable time.
In most cases the demand is postponed for minutes only, though some types of demand can be postponed for longer.

Here are few examples of the degree to which demand may be postponed.

Electric space heating, probably only a few minutes or the drop in temperature may be noticed. In exceptionally cold conditions even a brief interruption would be noticed.

Electric water heating in a cylinder etc. At least 15 minutes, and possibly some hours.

Washing machines, some hours in most cases.

Domestic refrigeration, up to about 10 or 15 minutes only
Domestic freezers, a few hours typically.

Charging an EV, at least an hour and in many cases several hours.

Domestic electric cooking, only a minute or two.

Air conditioning, industrial or domestic, up to about 10 minutes except in heatwave conditions when ANY interruption would be unwelcome.
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BritDownUnder



Joined: 21 Sep 2011
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Location: Hunter Valley, NSW, Australia

PostPosted: Wed Oct 12, 2016 12:59 am    Post subject: Reply with quote

New Zealand has been doing this for a while in turning on and off hot water control by various means including a 3000 hertz ripple on the 50hz waveform, a hard wire control and applying a 10 volt DC on top of the AC waveform.

This allows quite a local control of hot water demand.

Not quite as high tech but seems to work though I understand the system is beginning to get neglected. See below for a link.
https://vector.co.nz/documents/101943/111843/hot+water+and+load+management.pdf/98ae2a44-0a05-4b2f-bc06-25090c390338
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johnhemming2



Joined: 30 Jun 2015
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PostPosted: Wed Oct 12, 2016 6:55 am    Post subject: Reply with quote

PS_RalphW wrote:
https://www.theguardian.com/environment/2016/oct/11/energy-first-as-uk-successfully-transmits-data-via-national-electricity-grid

prototype demand control system on the national grid. Looks like a lot better use of
money than smart metres.

It depends how smart the smart meters are.
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adam2
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PostPosted: Tue Oct 18, 2016 7:18 pm    Post subject: Reply with quote

The national grid have just published the winter outlook report, which may be found here

http://www2.nationalgrid.com/UK/Industry-information/Future-of-Energy/FES/Winter-Outlook/

(click the above link to go to national grid website. Then click on "WINTER OUTLOOK REPORT" for details about the coming winter)
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adam2
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PostPosted: Tue Oct 18, 2016 7:41 pm    Post subject: Reply with quote

In summary, they expect a maximum demand of about 52GW.

The installed capacity is over 70GW but that is of academic interest, as no one would expect it all to be available.

The actual available generating capacity is expected to be about 54GW. The difference between installed capacity and actual availability has been calculated by use of historical data regarding planned outages and breakdowns.
One interconnector to Ireland is broken and is unlikely to be fixed before spring, and since that interconnector was used primarily to export, that saves 250MW.
One previously unavailable generating unit at Eggborough power station is now going to be available, giving an additional 430 or 500MW.

MY PERSONAL VIEW is that the report contains no blatant inaccuracies, but that it may be a bit optimistic.
In particular some old coal burning plant is to be used for meeting peak demand rather than for base load. Such use is non optimal and may increase the risk of failure, in plant already a bit "past it"

I also feel that a maximum indicated demand of only 52GW is a bit optimistic.

I recommend detailed study of the report if interested in such matters.
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adam2
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PostPosted: Mon Oct 31, 2016 8:18 pm    Post subject: Reply with quote

OCGT plant in use tonight, only a very little at 0.15GW, but it seems very early in the season to be resorting to this.
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Little John



Joined: 08 Mar 2008
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PostPosted: Mon Oct 31, 2016 10:13 pm    Post subject: Reply with quote

So, if I have got this right:

Selected appliances will be using a special plug-adapter that can limit the amount of power it draws from the mains, based upon data-signals it receives via the mains, about how much power is available, as a whole, in the mains.

Customers will be presumably incentivised to invest in these special plug-adapters via preferential tariffs or other similar financial incentives.

The first things that spring to mind are:

a) What is to stop rich people from simply buying their way out of any inconvenience such variable power consumption might otherwise impose.

b) On the other hand, if the financial incentives are sufficiently large as to dwarf any inconvenience, what is to stop relatively better off people taking advantage of this (a la the solar-roofing-subsidy fiasco) on the back of poor people.

This can only be fairly implemented if such specialist "smart" plugs are fitted, by law, to a range of devices and where there is no particular incentive nor cost to any particular consumer in having them.


Last edited by Little John on Mon Oct 31, 2016 11:11 pm; edited 1 time in total
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adam2
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PostPosted: Mon Oct 31, 2016 10:41 pm    Post subject: Reply with quote

Little John wrote:
So, if I have got this right:

Selected appliances with be using a special plug-adapter that can limited the amount of power it draws from the mains, based upon data-signals it receives via the mains, about how much power is available, as a whole, in the mains.
Customers will be presumably incentivised to invest in these special plug adapters via preferential tariffs or other similar financial incentives.
The first things that spring to mind are:
a) What is to stop rich people from simply buying their way out of any inconvenience such variable power consumption might otherwise impose.
b) On the other hand, if the financial incentives are sufficiently large as to dwarf any inconvenience, what is to stop relatively better off people taking advantage of this (a la the solar-roofing-subsidy fiasco) on the back of poor people.
This can only be fairly implemented if such specialist "smart" plugs are fitted, by law, to a range of devices and where there is no particular incentive nor cost to any particular consumer in having them.


Nothing involving special adapters will work, people might use them normally, but if the connected appliance "goes of just when I most needed it" then the adapter will be removed and the appliance plugged directly into the mains.
Special plugs permanently fitted to appliances wont do much better, people will remove them and fit a standard plug. And of course there are still installations that don't use 13 amp plugs.

Such load shedding contrivances will only work if built into an appliance at the factory in such a way that they cant be easily defeated or bypassed.
This could be encouraged by different tax rates on appliances, since most people base purchasing decisions on least first cost.
Most people would neither know nor care about the operation of any such device. How many people really notice if the washing machine takes 76 minutes for a cycle instead of 70 minutes ? Or that the fridge cut out on the thermostat for 18 minutes instead of for 13 minutes.

Some large or long hour loads might merit more detailed consideration, that requires a little user input.
For example an EV charger, or a bulk hot water tank might have three simple to understand pushbuttons.
Push button A to charge as quickly as possible regardless of cost.
Push button B to charge at a lower price, accepting up to an hours delay.
Push button C to charge at the lowest cost, subject to the delay not exceeding three hours.

I very much doubt that the rich would care any more than the poor if their laundry took an extra 6 minutes.
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Little John



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PostPosted: Mon Oct 31, 2016 11:12 pm    Post subject: Reply with quote

I actually agree about the risk of people simply detaching such devices if they prove inconvenient.
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Catweazle



Joined: 17 Feb 2008
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PostPosted: Wed Nov 02, 2016 12:27 am    Post subject: Reply with quote

Buy a diesel generator, get paid to provide backup to the grid.

Desperate times.

http://www.fwi.co.uk/business/business-clinic-backup-generators-can-earn-extra-cash.htm
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adam2
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PostPosted: Wed Nov 02, 2016 11:18 am    Post subject: Reply with quote

The economics of purchasing a generator for feeding into the grid at times of shortage are very doubtful.

If however the generator has already been purchased for standby purposes, then the idea has more merit.
If the capital has already been sunk for standby purposes, then electricity may be generated for little more than the fuel cost, without consideration of the interest on the already sunk capital.
Modest use is unlikely to noticeably increase maintenance costs or depreciation.

Requirements include
A reliable and well maintained generator.
A grid connection able to accept the produced power without undue voltage rise or other issues.
A reliable phone connection.
Sufficient fuel on hand for 48 hours operation.

The generator must be able to produce enough to make the costs worthwhile, and be efficient enough to be profitable after fuel costs.

I very much doubt that domestic generators would be suitable.

From the National grid point of view, such schemes are cheaper in capital and often quicker to implement than building more OCGT capacity.
Reliability should be excellent since a large number of small (by grid standards) generators are involved. Some will no doubt fail to start when called upon, but I would expect most to start, and the actual electricity produced would be at least 80% of the connected capacity.
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adam2
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PostPosted: Fri Nov 11, 2016 8:58 pm    Post subject: Reply with quote

To add to the points already made, it should be noted that rota power cuts if long continued and/or often repeated tend to become steadily less effective in reducing electricity demand.

In the short term, the cutting off of one load group out of 18 such load groups will clearly reduce demand by about one eighteenth of the national total.

If however rota cuts become a regular feature, then they become less effective.
Each load group has a boundary, and across this boundary will be strung extension leads or larger cables so as to obtain power from whichever area is still on.
Also when the power is restored to one load group, the demand will be greater than normal due to thermostatically controlled heating and cooling appliances "catching up" and also postponed demand such as the person denied a hot shower during the cut, who takes the shower as soon as the supply is restored .
Businesses with several premises will tend to transfer demand to those addresses still on.
And so on.
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adam2
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PostPosted: Tue Nov 15, 2016 5:12 pm    Post subject: Reply with quote

As discussed elsewhere, France faces an electricity shortage due to concerns at a number of nuclear power plants.
This slightly increases the risks of power cuts in the UK since we were expecting to import about 2GW fairly consistently from France into the UK.

It now seems unlikely that these imports will be available.

No problem at the moment since our nukes producing at near record levels, the weather is mild, and wind plentiful.

A series of breakdowns or a sudden cold spell could be interesting.
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