2 electricity supplies to one building

Simon, I know that you are very pro electric vehicles. It would be most interesting if you would explain to the rest of us how you intend 40 million of them in a few (by infrastructure times) years to be charged? We are not anti-electric vehicles per see, we just don't know how to provide the necessary infrastructure. Many streets have cables feeding 150 houses with a single 400A fuse in each phase. If 6 houses take 100A continuously this fuse will blow in an hour or so, to great inconvenience to the rest who are taking no current at all! A short period, even at 100A is not the charging time for most vehicles, remember too that battery capacity is increasing by the week it seems. A vehicle with a 100kWh battery will take probably 6 hours at 100A to charge, in electrical time that is not a short period. You are assuming each vehicle is not driven far every day, that does not match the commuting statistics outside London, for example. Simply where is the electricity coming from (totally reliably), and how will it be distributed? Easy questions I am sure. And very relevant to the Wiring regulations moderator!

Mike,

Being a clever fella would you be up for speculating where this is going? We have solved the individual MD issue with load curtailment devices but if there is a speedy uptake of EVs, the local transformers will be swamped. I mentioned OCPP in an earlier post which could be used by DNOs to wind back demand but whether folk would accept limitations being imposed by a big brother somewhere remains to be seen.

I will break in, please Lyle, we are heading for disaster. Have you looked at the news from Texas (probably not the Greenest state) that cyclic power cuts have been operating for several days because the wind is not strong and the turbines have frozen up. What about the poor citizens who are not used to sub-zero temperatures, and are famed for fairly short tempers with this kind of thing?


I will adda bit more too Mike, it is as your very interesting paper cited says, it is the transformer the cables, the HV transformer the HV cables and everything. Just a bigger transformer doesn't solve much at all!

Well, I think the era of DNOs maintaining a 1950s network on a fire brigade basis (literally some times - link box fires and so on) will draw to a sharp close, especially if the expected drive to push folk off natural gas happens as well.

As it stands, none of the infrastructure is adequate for that sort of increase in demand. So, no, it won't happen quickly - look at how long it has taken to replace fused neutral cut-outs from the old DC days, (almost a century on, and a few are still in service) or to give  give everyone a smart meter - which are chicken feed compared to the upgrades that would be needed, so right now it is all so much hot air and aspirations.

The fastest fix might be to go up a bit in voltage, and put in 33kV where 11Kv would normally go (as already in Scotland on long lines and London on heavy loaded ones) and 690V instead of 400V.   A lot of cable could then be retained but certainly not all of it.

M.

The standard home charger is only 32A, so nowhere near the 80 or 100A of a supply fuse.  The average UK person only drives a few tens of miles a day, in a car that might do 150 to 200 miles on a charge.  So most of the time any given car will not be charging.


If the supply is inadequate, or if the customer only has a 60A supply that can't be upgraded, then the charging rate can be reduced to 16A.  That's still enough to mostly recharge a car in one night.


If the DNO's infrastructure needs upgrading to allow for EVs, then it needs upgrading.  That's why we all pay a standing charge on our bills.  Arguing that we shouldn't do something because our obsolete 20th century infrastructure can't cope seems so backward.  The local gas supplier in my area gas been going around digging up the roads to replace obsolete cast iron and steel gas mains with shiny new plastic ones, because it needed doing.  It shouldn't be beyond the ability of DNOs to reinforce their infrastructure if that's what's needed.

It isn't beyond the DNOs to upgrade the network, but it will need planning and the doing, and in a very big way, and costs will have to rise -a lot- to cover it,  that is the point - the early adopters are for now freeloading, which makes adding charge points look much cheaper than it really is, and it will take time. We have been doing the cast iron gas main replacements you mention since the mid 1980s, and still are, so it is reasonable to allow a similar 30-40 year time frame for redoing the electrics.

Here is why.


Mean while the 100A fuse does not come into it, it is the fact  that all the network behind  it is sized assuming  about 10% of that load, something more like 10 A per house long term , and relies on loads averaging out to less than that over any reasonable period compared to the time it takes to get the transformers and cable heated to a dangerous temperature. (and looking a bit further back - we may have generation issues - we have  approx 24 million dwellings in the UK   and   perhaps  80-85GW of generation and import capability flat out of which 30% or so is available for domestic say 25GW to be be generous - that is only about like 1.05 kW each house average, and that ignores transmission losses )

Unlike storage heaters, where the load is most heavy in winter and time shifted to be at night when factories are not running, and then it is cold so cable and transformer ratings are higher, cars will presumably be needed in summer too, and maybe some will want to charge at work during the day ?

Electric cars are a good idea from a pollution perspective, and will come in due course, but they will be nothing like as cheap to roll out on mass as they appear at the moment, a dose of realism is needed.

M.

Hi Simon


Asking the consumers to pay about £3trillion over the next ten years is delusional of the first order. You need to build probably 10 or more nuclear power stations, rip up 100,000 miles of roads, build many hundreds of miles of new EHV lines buy more new transformers than have ever been made at once, and employ every civils contractor in the country for the entire period. You will need to buy a significant proportion of the world's production of copper, aluminium and polymers for cables. A couple of kilowatts for a few hours really doesn't take you far, particularly in Winter. Basically, you are asking the UK to become like Texas at the moment, to have rotating power cuts, and no transport at the same time. The disruption to traffic in towns would bring life to a halt.


I am not anti-electric cars, but the owners should pay the full real cost, just as the users of fossil fuels do. We do not expect free new oil wells, refineries, supertanker ships, distribution pipelines, and Petrol Stations as the Greens seem to for the equivalents for electric vehicles, they are clearly economically illiterate, but very good at propaganda. Germany is retreating from this quite quickly, they are building coal power stations, because the wind and sun are too expensive and do not work, giving them only very expensive, unreliable electricity. China is building at least 2 coal stations for every one decommissioned in the West. I assume you have an electric car and travel few miles. How is the heater when there is snow on the ground, and how much range is there with full heat? It looks as though you are expecting everyone else to subsidise the "Electric Dream" to the extent of about £30 million for each car. How kind. How does this do anything useful at all, even if you believe CO2 is a monster? Just consider how much fossil fuel will be needed to do all this work, and how much concrete (the new pariah I hear) and bitumen will be needed to do the job. I am still waiting to see electric pavers and proper lorries, excavators and 2000hp bulldozers on sale. They are simply not scientifically possible. Take a 44-tonne artic, They often drive 20 hours a day (multiple drivers) and have 5-700 hp engines. They would need interchangeable battery sections and would suffer considerable load space and weight reduction as a result. At this time they carry sufficient fuel for 1000 miles of motorway driving. 1000 mile battery, = zero load capacity! Ha, another really good idea. I know, railways! How much is HS2? The practicalities of rail freight are terrible too, that's why there isn't much.


Do you really believe this is the future of electricity? It would be nice if you answer this because when the electrical collapse occurs, it is unlikely that BS7671 will have any relevance any more, people will be dying in droves.