Green Building Forum - Not enough power available Tue, 19 Dec 2023 08:27:40 +0000 http://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 Not enough power available http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303257#Comment_303257 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303257#Comment_303257 Wed, 13 Sep 2023 16:55:23 +0100 borpin
Basically, if you ban the fitting of boilers, and force the installation of HPs and require EV Charging, the local infrastructure requires more power and the Grid cannot support it.

They cite a development near us that the initial planning was for 8MVA but it now needs 35MVA. They can only get a 15MVA connection from the grid.]]> Not enough power available http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303258#Comment_303258 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303258#Comment_303258 Wed, 13 Sep 2023 17:24:32 +0100 WillInAberdeen
New homes built to the 2022 Scottish building standards need almost no heating, a kW or two, it wouldn't be economic to lay gas mains and fit boilers for such low heat demand. If they do have say 5kW heat pumps (over sized) then 1.5kW electricity supply each will be plenty, so 1.5 MW for every 1000 houses. Heating is not what they want 35 MW of electricity for!

Possibly they are thinking about electric cookers (10kW per house) or car chargers (7 kW, but not everyone at once)?

This story allows the Telegraph to bash both heat pumps and the SNP all at once, so I wouldn't expect arithmetic to stand in the way!

Edit: and that development started building way back in 2012, it wasn't held up by some unforeseen electricity supply problem with boilers in 2024. Sounds like someone screwed up and is looking for imaginative excuses to ask for more money!]]> Not enough power available http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303263#Comment_303263 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303263#Comment_303263 Wed, 13 Sep 2023 22:27:55 +0100 Jonti Posted By: WillInAberdeenI smell a rat somewhere... someone hasn't checked the numbers!

New homes built to the 2022 Scottish building standards need almost no heating, a kW or two.

I work in the Scottish building industry almost none of the houses being built by the big house builders meet the current building standards. The theory is great however the lived reality for most new home owners is different.]]> Not enough power available http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303264#Comment_303264 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303264#Comment_303264 Wed, 13 Sep 2023 23:05:16 +0100 WillInAberdeen
And even if they used 3x or 5x more heat than the law requires, they still wouldn't need 35 MW of electricity for heating their housing development. If you put 35MW of electricity into heat pumps, you get 100 MW of heat out, enough for a whole town.]]> Not enough power available http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303266#Comment_303266 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303266#Comment_303266 Thu, 14 Sep 2023 07:06:45 +0100 borpin Posted By: WillInAberdeenso 1.5 MW for every 1000 housesI do wonder, but equally, it talks about MVA (not KWh) so this is about all of them to be on at once (total potential load). The sources seem reasonable as well.

Where you only have an 80A supply, this can be an issue with HP & EV apparently.

[edit]
I have seen other news items from different sources saying certain developments cannot go ahead as there is insufficient capacity in the Grid.]]> Not enough power available http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303267#Comment_303267 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303267#Comment_303267 Thu, 14 Sep 2023 08:43:13 +0100 WillInAberdeen
MW is the same as MVA if we have pf=1 (which we should) - sometimes a little different for industrial sites with big induction motors. Yes indeed the actual load will be less than 1.5MW per 1000 homes, because not everyone will be running their heatpump flat out at the same moment.

An 80A supply is 18.4 kW , which is plenty for a 7kW EV charger to run simultaneous with a 5kW heat pump (IE 1.5kW electric draw) and also a cooker, kettle, and a hundred lightbulbs and a huge TV.

Many (most?) EV chargers now come with a current clamp that goes on your mains, so if you are getting close to 80A it will slow down charging the EV a bit. Also comes with a timer to charge the EV overnight when the other loads are off.

Housing is often held up getting utility connections, usually drains and sometimes electric. Has always been so, is nothing to do with heatpumps in 2024, despite what the Telegraph prints!]]> Not enough power available http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303270#Comment_303270 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303270#Comment_303270 Thu, 14 Sep 2023 09:54:49 +0100 WillInAberdeen
1.5kW per house + 2.5kW per Fast EV charger + capacity of heatpumps

So for 1000 homes with EV chargers and small heatpumps they'll want (1.5 + 2.5 + 1.5) = 5.5 MW, of which 1.5MW for the heat pumps.

Nowhere near the '35MW needed because of heatpumps' claimed in the paper. Presumably the 35MW is actually for the industrial and retail developments nearby.

https://www.spenergynetworks.co.uk/userfiles/file/ESDD-02-012.pdf]]> Not enough power available http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303271#Comment_303271 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303271#Comment_303271 Thu, 14 Sep 2023 11:57:30 +0100 djh
It's conceivable that heat pumps could be required to have similar control capability, so their demand could be similarly levelled, though not at present.

Cookers come in various types, but just considering induction hobs, ours has a c 40 A, 10 kW max demand and it would be difficult to legislate against them all being used at once. Similarly some firms (I'm looking at you Neff) produce hobs that are limited to 13 A demand but I can't imagine them being made compulsory. Running a wok would be very difficult, although I know some who do. At that sort of level we're probably back to the classic maximum load of a gazillion kettles being turned on at half time in a football match.

That SP Networks ADMD calculation is weird. They add up various things and average them in a complicated way when what they're really doing is just totalling the demand and dividing by the number of houses. All the kerfuffle in the middle to get an 'average' is just a waste of space.

They also use the term 'Heat Pump capacity' exactly once and don't define it. If asked, my first guess would be that meant the output capacity, but from the context I presume they mean the input electrical demand.]]> Not enough power available http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303272#Comment_303272 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303272#Comment_303272 Thu, 14 Sep 2023 12:42:18 +0100 philedge Posted By: WillInAberdeen
1.5kW per house + 2.5kW per Fast EV charger + capacity of heatpumps

So for 1000 homes with EV chargers and small heatpumps they'll want (1.5 + 2.5 + 1.5) = 5.5 MW, of which 1.5MW for the heat pumps.

As I understand it not so long ago the diversified design load per house was 2.5kw, so a new diversified load of 5.5kw per house is more than doubling required grid capacity.

Hope someone has a coherent plan for world electrification.]]> Not enough power available http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303273#Comment_303273 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303273#Comment_303273 Thu, 14 Sep 2023 17:11:54 +0100 borpin Posted By: WillInAberdeenSo for 1000 homes with EV chargers and small heatpumps they'll want (1.5 + 2.5 + 1.5) = 5.5 MW, of which 1.5MW for the heat pumps.

From the item -

The SPF raised the example of a very large housing development being built in Winchburgh, West Lothian that originally required eight megavolt-amperes (MVA) of electricity, before the gas boiler ban was announced.

For the moment let us assume this is correct (I doubt they would try bringing false facts to a committee meeting) this is for 3,400 houses.

So by your calculation, the old figure would be just over 5MVA (1.5 * 3,400)- allowing for infrastructure (there are 2 high schools and a primary school alone) their stated old figure of 8MVA seems reasonable.

At 5.5KVA per house, 3,400 would come out to 18.7MVA a fair bit below their 35MVA, but still a significant increase.

They may be enhancing their argument, but the basis, that they need a much bigger grid connection, isn't wrong and it may well be that the grid cannot supply it.]]> Not enough power available http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303275#Comment_303275 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303275#Comment_303275 Thu, 14 Sep 2023 18:15:10 +0100 chrisinbrighton A good plumber I know said he thinks alot of houses will need threephase to spread the demand.]]> Not enough power available http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303276#Comment_303276 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303276#Comment_303276 Thu, 14 Sep 2023 18:16:15 +0100 chrisinbrighton Not enough power available http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303277#Comment_303277 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303277#Comment_303277 Thu, 14 Sep 2023 20:54:25 +0100 djh Posted By: chrisinbrightonWhat about electric sowers (12kw) having a shower in winter whie someone is having a cup of tea...It's not the demand in an individual house that is a problem, it's the overall demand from all the houses together. The Scottish document reckons the supply to each house is 80 A (dunno why, ours is 100 A) which is approx 20 kW (or kVA if you must) so a 12 kW shower plus a 7.36 kW EV charger would be getting up to the limit. Hopefully the charger is smart enough to throttle back if somebody puts the kettle on :devil: I think most showers are 8 to 10 kW though. The 'diversity' calculation assesses the chances of people using high power at the same time in multiple houses. Evidently for car chargers they reckon people all charge overnight and charge one day in three on average (or thereabouts)]]> Not enough power available http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303281#Comment_303281 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303281#Comment_303281 Fri, 15 Sep 2023 09:02:18 +0100 WillInAberdeen https://www.linkedin.com/pulse/uk-electricity-networks-need-rapidly-sort-heat-pump-standards-lowes



Another cracking anti-heatpump story in the Telegraph today, heat pumps are all apparently a Chinese plot to control the world with Putin! Wondering if they're using AI bots to write this stuff.

Can't find it now but was reading a while back that 'PV is a problem' (a change from blaming 'heatpumps and EV chargers'!) The story was that DNOs used to set their transformers up at 253V to overcome cable resistances during peak winter demand, so the supply would still arrive at the homes within legal tolerance of 230V±10%. But then if everyone is exporting PV, the voltage in the homes goes above 253V on a sunny day. So the transformer voltage setting has to be reduced and then cannot deal with peak winter power demand.]]> Not enough power available http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303282#Comment_303282 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303282#Comment_303282 Fri, 15 Sep 2023 10:12:03 +0100 Artiglio The chap that did the change, was of the opinion that there was a push towards making 80amps the norm because so many homes already had them with supply cables that could’nt take 100 amps , that if the industry accepted 100 amp supplies as the norm in the future if the drive for electrification was successful vast numbers of homes would need upgrading of the supply cables, with the attendant costs. So from the DNO’s point of view it was better to encourage better consideration and design in homes as to the amount of electricity required.

He also said that whilst not a massive problem , they had regular call outs to homes that were having issues, the recent addition of a car charger usuallybeing the last straw, having been installed without sufficient regard to the homes existing useage and age/condition/quality of the consumer unit ( more recent wylex boards being seen as more likely to have issues). He said the reports from such visits were collated and dissected to see how things should be guided going forward.

But when asked what the biggest problem was he saw, “unauthorised connections ” was the swift response.]]> Not enough power available http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303297#Comment_303297 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303297#Comment_303297 Fri, 15 Sep 2023 23:39:12 +0100 Mike1 Posted By: ArtiglioMy house had a 60amp fuse when i moved inThat's a typical connection for an electrically heated house in France - the maximum monophase connection offered, I think. For those on gas, it's typically 30A. Around 70% of all domestic properties, including apartments, have a 30A connection.

That's low compared to the UK for 2 reasons:
- the power chosen determines the standing charge, so there's an incentive to keep it low (a 60A connection costs in the region of €19/month, 30A around €12.50, down to €9.25 for the minimum 15A supply)
- a load-shedder can be fitted to the consumer unit that temporarily disconnects one or more selected low-priority loads (water heating, central heating, washing machine, etc.) if the total load approaches the maximum - for example while fully using an electric hob.

Because France relies much more than the UK on electric heating, it has a much higher electricity demand (around 50% more) - more like the UK needs to become as it transitions away from gas. It may well be that the UK needs to consider a French style charging scheme to help moderate the grid expansion that will be required.

Posted By: WillInAberdeenSeems some DNOs are standardising on 80A supplies now
Posted By: Artigliothere was a push towards making 80amps the norm
Looks like that is now National Grid policy - https://connections.nationalgrid.co.uk/news-and-events/latest-news/standardisation-of-fusing-to-80a]]> Not enough power available http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303300#Comment_303300 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303300#Comment_303300 Sat, 16 Sep 2023 10:55:00 +0100 djh Posted By: Mike1Looks like that is now National Grid policy - https://connections.nationalgrid.co.uk/news-and-events/latest-news/standardisation-of-fusing-to-80aYes, for some DNOs at present. My DNO - UKPN - still supports 100 A and there are calls for a national standard to be agreed one way or the other. Lots of bun fights ahead :bigsmile:]]> Not enough power available http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303301#Comment_303301 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303301#Comment_303301 Sat, 16 Sep 2023 11:00:08 +0100 Artiglio If it weren’t for the woodworking 60amps would probably be enough for me ( whilst heating with gas ) unless i put a car charger in , but even then if it were intelligent ( my description) I wouldn’t forsee many problems. My usual consumption is around 8kwh / day , with workshop use on top and even then an enthusiastic day of making shavings and dust might top that out at 30 or so.

I’ve put in extra cabling to enable me to fit an electric boiler or ashp in the future ( for a brief period i bought into the notion that eventually electricity would be so plentiful as to be cheap enough to rely on resistive heating, with a woodstove supplement in cold spells, but have moved away from that occuring in my lifetime) but with the push toward 80 amp supplies , i’m guessing that any request for 100 amp supplies is going to leave the consumer liable for the upgrade costs, for which i see costs in the future will include an infrastructure charge similar to those imposed by the water companies. Which means i’m planning it all around the current going forward.]]> Not enough power available http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303304#Comment_303304 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303304#Comment_303304 Sat, 16 Sep 2023 12:09:17 +0100 owlman Request confirmed and the free upgrade went ahead including some new incoming tails.
Fast forward 12 months and I decided to ask my electrician to install a a 100A double pole isolator in the meter cabinet. He discovered on pulling the main fuse that the fuse cartridge itself was in fact 80A although clearly labelled as 100A on the outside casing.

P.S. The electrician said, " they do this all the time"]]> Not enough power available http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303305#Comment_303305 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303305#Comment_303305 Sat, 16 Sep 2023 12:16:56 +0100 Artiglio Not enough power available http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303306#Comment_303306 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303306#Comment_303306 Sat, 16 Sep 2023 12:21:11 +0100 jms452
The level of discussion/knowledge on GBF is in a different league - thanks:bigsmile:]]> Not enough power available http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303308#Comment_303308 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303308#Comment_303308 Sat, 16 Sep 2023 12:53:41 +0100 owlman Posted By: ArtiglioOwlman - was that new tails from the main fuse or did your upgrade include a new cable from the “road” ?


The supply, is from a pole on the opposite side of the road from my property, it passes under the road and into a chamber near my boundary and then under my front garden to the meter box on the house wall.
The contractor dug a hole in the garden to locate the conduit and then split it and installed new tails back to the chamber and forward to the meter box. The total distance is about 25M, give or take. The originals were 16mm and they've been upgraded to 25mm.]]> Not enough power available http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303311#Comment_303311 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303311#Comment_303311 Sat, 16 Sep 2023 15:34:44 +0100 djh Posted By: owlmanThe contractor dug a hole in the garden to locate the conduit and then split it and installed new tails back to the chamber and forward to the meter box.That sounds strange. I wonder why they didn't just pull through a cable from one end to the other. Is the conduit bent or something?]]> Not enough power available http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303316#Comment_303316 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303316#Comment_303316 Sat, 16 Sep 2023 16:17:57 +0100 WillInAberdeen Posted By: owlmanHe discovered on pulling the main fuse that the fuse cartridge itself was in fact 80A although clearly labelled as 100A on the outside casing.Ours is the same, I think that's normal. It means the fuse holder unit can handle up to 100A (80A fuses are the same size and are normally what's fitted). Same as with a 13A plug or FCU that can have a 5A or 3A fuse fitted, the only way to know what's inside it is for the electrician to open up and look!
It would be nice if they put a sticker on it or something to help with planning. If you have an electrical inspection report then the fuse rating might be written on that, if it was opened.]]> Not enough power available http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303317#Comment_303317 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17951&Focus=303317#Comment_303317 Sat, 16 Sep 2023 16:20:56 +0100 owlman Posted By: djh
Posted By: owlmanThe contractor dug a hole in the garden to locate the conduit and then split it and installed new tails back to the chamber and forward to the meter box.
That sounds strange. I wonder why they didn't just pull through a cable from one end to the other. Is the conduit bent or something?

Yes, and yes.]]>