UKC

As the previous thread is full....

In response to Graham's question about spare overnight capacity - not only is there spare generation capacity (as mentioned by Jamie), there's also spare network capacity - distribution networks are sized to deal with peak load, so additional off-peak load is no problem until it becomes the new peak. Electric cars aren't the problem for the network, electric heating is, but even then there is still scope to alter tariffs to spread the load.

You got me thinking about cabling local to houses. If everyone in a particular road has a 7kW charger can the local cabling cope? I don't suppose it was sized for this sort of load.

Agreed; I'd even take a menu command to adjust the assistance level; seems to me that a bit of lag in the control loop would give you some sense of the demand on the steering...  Funnily enough the only electric power steering I've used and not despised was on an MP4-12C I had use of for a few days.  

The racing game on the Tesla model 3 touch screen is played when parked by turning the steering, scrubbing the poor tyres. Perhaps the deadzone is to save the tyres; that seems to fit the mindless approach to UI on that car...

You could take over ranting for me, fully qualified.  The Leaf in eco mode can roll back a bit on a steep hill; absent a manual handbrake it encouragers left-foot breaking as a clean way of getting going; then when you think about it there's no reason not to keep left-foot breaking...  The ePedal mode does away with the eco mode hill start issue, but I've never taken to it - I try and avoid regeneration by driving ahead, just as with avoiding brakes on the diesel burner.  Having just Ubered across London in a Leaf I can see where people would use it.  

That's about the same load as boiling the kettle while running a hairdryer.

My pyrolytic oven uses 8kW on a cleaning cycle.

My induction hob is 7.5kW.

You have to inform the DNO when fitting a dedicated charger, and they'll check that the local infrastructure can cope. 

We're looking at fitting EV chargers to the 27 flats parking spaces here, and what will probably happen is that the first eight or ten who get connected up will be able to have full fat 7kW, but after that they'll start to be downrated.

It's a valid question but 7kW in a domestic context isn't that high, it's basically a big oven equivalent, nowhere near a shower.

The issue is where the charging loads are synchronised (because they're quite persistently present while people are home) and additional to existing loads. I suspect some infrastructure will be found wanting but most will cope.

There are possible technical alternatives without re-cabling if we run into problems. For example one could in theory monitor the household draw and throttle the car charger while transient heavy loads like electric showers or preheating ovens are present, the net effect on charge rate would be negligible and such behaviour could be incentivised through the tariff. I suspect in most cases it'll not prove necessary and where it does the infrastructure probably needs attention anyway.

Adding charging to a significant base-load of on demand electric heating is harder to deal with than transient loads like cooking and showers!

Haven't most houses had their main fuses de-rated from 100A to 80 or even 60A anyway over the years? Not sure why that was done, possibly to add houses to the network without re-cabling!

jk

Just live anywhere with hills, and regeneration is essential. Seeing your remaining range shrink on the way up and grow again while maintaining a constant speed downhill is rather satisfying!

I reply to Jamie Wakeham:

Charging speed is higher across the range. Between 20% and 80% the car usually draws between 140 and 160 kW.

CB

We're about half hilly and half flat on our journeys.  Agree the regeneration is more essential on hills, but on the flat it generally means less economy (round trip energy losses) than looking and driving ahead.

Although it can be a bit alarming to see 10 miles range left with 40 miles to go to get home, one just has to trust in the laws of gravity and conservation of energy.  It would be nice to have a hill-aware energy usage estimator for a journey, but you suss it out in the end.

I meant to reply to an earlier post of yours on the previous thread; have you tried charging on a 22 kW AC inlet?  Surprise - it's 11 kW I think for you model; not many vehicles support more than one phase (~7.7 kW/phase) and of those that do, not all support charging at the full potential through their onboard charger.  Much confusion abounds over the 22 kW posts...

I have not used 22kW chargers yet. Maybe I should try, I have one at my work car park, but mainly I use the 150kW charger at my village hall.

CB

Ooh - nice. Yes, that does make my 45kW or so feel a bit outdated already.  That must be about 500mph?

It's nice to see someone mention whether the Electricity network *Will* actually cope with the growing number of Electric cars, rather than whether the grid has capacity for the extra Electricity required. There is a massive amount of work to be done on the low voltage side of the distribution network to come anywhere near being able to have an all EV enabled cable network. Some - most, of the cabling isn't physically big enough to cope with the extra load. Rows of terrace houses all fed of the same cable, semis, looped together on the same phase with the equivalent of a 16mm cable feeding them both.

We have just been involve with a new charging station being built. From their HV Transformer to their control panel, three 600mm copper cables per phase to feed seven 150kw chargers. From there the Transformer eventually connects to the DNOs overhead HV line, which is 40mm Aluminium. Which won't be upgraded because no one will pay for it to be done. We're heading into a real big problem with a very old network that wasn't built for the load we will be requiring it to supply.

As I understand it, pretty much the only cars that will do 22kw are Zoes, plus some older Teslas (mostly Model S). There are quite a few 'premium' car brands will sell you a 22kw onboard charger as an expensive option but I doubt many people take it up. Most do 11kw now, some only 7-8kw. (As I understand, the 11kw charging cars generally have three phase 16A per phase chargers, of which two can run together on single phase to provide 32A charge - I don't really understand the details.)

I have already taken the slightly controversial view that for people with driveways, all 'destination' slow chargers are a waste of time anyway. I'd rather see investment continuing in to rapids so that I never have to consider plugging in to an AC post.

Wait until you have to do a truck one!

There's a small/medium haulage company in the next town (230 trucks) that do primarily local run building material runs and they are part of a feasability study into going to EV.

The local power company were asked about the power supply to their truck park and their dry reply was "build a power station next door". The proposed truck system (MCS) is 3.75 Mw at 1250V per outlet.

Not a controversial view at all! I don't (yet) have a home charger as we are currently renting an upstairs flat.

Whether I will even bother to install one once we get to move into the house we bought will depend on the price differential between rapid charging (conveniently doable near work or during training in the evening) and overnight AC home charging. If it is only a few cent per kWh (i.e. it would take more than a couple of years to recoup the costs) I may well stick with what I am doing right now.

I've no idea of the economics in Germany.  In the UK, though, it's typically 40p/kWh on a rapid, compared to 15-20p/kWh for domestic supply.  Overnight EV tariffs are cheaper again - I'm still on 5p/kWh between 00:30 and 04:30, though this is going up to 7p when my fix ends.

Si dH - I seem to have managed with my 2.2kW charger for the last six years!

If the power peak relating to night charging is no bigger than the peak relating to existing daytime consumption then I'm not convinced the HV network has any great new issue unless there are a small handful of *massive* industrial consumers with day-heavy diurnal usage patterns and their own HV connections?

I can well believe suburban supply design has in places become evolution and is not ideal, in others doubtless it is in poor repair but I struggle to believe that 7kW/house overnight is impossible, overnight 2.5kW charging would suffice for the majority of users most of the time. Where there are local problems superimposing that on big pre-existing transient loads (cooking and electric showers) I suspect the fix will be smarter chargers* (this will be driven as much by highly variable tariffs as technical limitations but the tech is much the same). Battery electric cars are coming and I think will be here to stay for decades so where there are problems we will have to face them one way or another. Some of it may be through network upgrades but I suspect until we start also adding widespread domestic electric heating we'll be looking more to electronic sticking plasters.

*Chargers which prioritise buying energy at the cheapest rates minimising bills and creating virtual storage, chargers which minimise their charge rate based on programmed or predicted vehicle usage patterns rather than running flat out from 18:00 to 23:00 every day loading the grid at dinner time when prices are highest and supply issues greatest, chargers which tightly integrate with local solar, perhaps even chargers which manage total household consumption within agreed bounds where severe local problems exist.

As to whether we will upgrade the network. Yes if we need to. Afterall we built it and the one before it and the broadband network, telephone, telegraph and the gas and hydraulic power networks before them. The idea of building a network of motorways for example seems impossibly huge and unimaginably expensive a task now but we needed them so we started building them and over time they grew. Or think of the arguments over new rail lines, bitter and protracted for sure but slowly they get built and they will likely still be serving our great grandchildren alongside those built in the 1800s. I see no reason why other infrastructure is any different. We might need to change the funding and ownership model for essential public goods like power and sewerage if private capital continues to fail to deliver but if we need it there is no alternative to building it, history teaches us it is possible.

jk

I was about to write something very similar.  A 'normal' 3.5kW charger is fine for almost all users (as I said above I get on just fine with 2.2kW).  Even the 7kW ones are fairly quick for destination charging and probably overkill in most cases.

That 3.5kW charger is essentially like a kettle with the switch taped down.  Given that there are big incentives to do this mostly during the dead of night, in most cases the existing setup will suffice.  We do need to train people out of the mentality where they just plug straight in at 6pm when they get home, coinciding with the evening domestic surge.

Sorry, to clarify, I wasn't saying home chargers are unnecessary (I have one and use it as much as possible for cheap charging) but rather that I think 7kw or slower chargers (which I refer to universally as slow because calling a 7kw charger 'fast' is bonkers) away from homes are pointless. The caveat would be a need to find a solution for people without home charging.

Basically, my logic is this - if I'm going on a long journey where I need to charge away from base, I will never leave myself reliant on a 7kw charger (eg at a hotel or shopping centre) because there is too much likelihood that I arrive to find someone else sat on it for 12 hours, or if I get on it but then it fails randomly after an hour or two (especially in the middle of the night) it's unlikely to be convenient for me to go and restart it. So, I always plan to use rapids such that I don't need to charge at the destination. That makes it just a nice-to-have, at which point I conclude investment is better spent elsewhere.

Some EV drivers have a vision of some utopia with 7kw chargers in every parking space but I think that's totally unnecessary and the wrong direction, especially given the direction in terms of AC and DC car charging speeds. I'm all for ultra fast rapid charging hubs.

Though electric heating used to be very common - pretty much everyone's Nan had a coal fire and a 2-bar classic electric fire for when they couldn't be bothered lighting it.  I suspect loads are actually lower typically at the moment than they were back then - OK, there's more electronics, but most electronics are very low load, while lighting is almost all LED and heating almost all gas.  Gas back then was typically less for heating and more for cooking and possibly one of those above-sink water heaters.

A 2kW electric fire won't provide a lot of heat, but a 2kW heat pump will.

And if the grid can handle a 2kW electric fire during the day, it can handle a 2kW car charger at night.  Not a fast charger, granted, but you don't need a fast charger if you're going to plug in all night, every night, like most people do with their mobile phone.

Ay although I disagree slightly with the last bit. Nobody wants to be going out last thing before bed in the rain to plug the car in, we need to make it as easy as possible to do the right thing without training or caring, just let the technology handle it and provide an economic incentive to encourage people away from subverting it, 'taping the switch down' if you will

jk

I'm averse to rapid charging as we're a Leaf and it's not got active thermal management on the battery pack.  It's an occasional thing not a core part of how we charge unlike for some others.  

But it's clear rapid chargers meet far more people's needs than destination charging, and in terms of investment vs use, destination charging dilutes use and rapid concentrates it, so it's a smarter use of money.  

But destination charging is very effective, and it needs nothing more than a 13A outdoor socket and a DC sensitive RCD/RCBO.  It's worked incredibly well for us; we're looking forwards to 7 days away in the wilds of Northumberland without any need to visit a charger, ever.  You start to get glimpses of a possible pure-BEV future that is eventually way less hassle than ICE ownership.  Took me some time to fill up the secondary car, a diesel burner, yesterday as one 1 diesel pump was on...  At some point we're going to see a death spiral for ICE, as fuel stations wind the fossil business down, meaning ICE owners have to go further out of their way for fuel, pushing more people to BEV...  

In other news, I saw an EV charging whilst parked on the road outside a mid-terrace for the first time today; 13A outdoor socket on the front of the building, and a granny cable run through a plastic strip over the pavement; tidy, pedestrian and pushchair friendly and no fuss.

In reply to jkarran:

A lot of cars have charge timers, and mobile phone apps to handle that sort of thing.

Surely you have much joyous experience to report from the Leaf's App?  I still struggle to understand how they made that so incredibly awful.

Someone mentioned the other week that they had to have a relay installed on the circuit to the BEV charger that would cut it off whilst the load from the shower etc became too much.  Simple and effective, and retrofittable to many households, just so long as you can get a current clamp on one of the tails or other relevant wires.  I bet ALF wishes the hairdryer socket on his spaceship had had one of those.

Whizz into an Ionity charging station on the autobahn and it's 0 79€!

...ouch!

Si dH - ah - yes, I agree.

Jkarren - for me at least the car handles all this. I just tell it when my off peak times are, and I can choose whether to charge at just off peak or at an times, and how far to charge to.

I think slow charging at all long stay type parking facilities and at home will just become the norm.  If you always plug in (potentially we might even see other options like automatic inductive charging, which is already possible and was used for an electric bus trial in MK) you won't need to actively charge at all unless on a very long trip.

While it does involve rather heavier infrastructure, look at how USB sockets have become the norm everywhere and anywhere you might want to top up your phone.

Pretty much what I was thinking, if the grid can serve peak between 4pm - 7pm by spinning up a few peaker plants then it will cope with the vast majority charging their cars 12.30am- 5am on incentive tarrifs (octopus go) / Grid intervention (smart chargers) . The person at National Grid to follow is Graeme Cooper who I think is something like Project Director, anyway he's the person I presumed tasked to make this happen and they don't see it as an issue (perhaps with some local DNO upgrading). What he thinks will become the big issue is electric Central heating presumably because it's on demand (rather than can be scheduled and controlled thru the night like ev charging). 

Just using the first numbers I find with Google for an estimate...

...average car mileage UK is 18 miles per day and electric cars average 0.346 KWh per mile.

So an average overnight charge is about 6kWh or less than a 1kW through the night!

That is bugger all. Can it really be so little?

If it really is 1kW average, I don't see why that would require much of an upgrade unless the grid is already right at the limit on a cold night. Which I doubt as otherwise economy 7 wouldn't have been invented.

https://www.bymiles.co.uk/insure/magazine/mot-data-research-and-analysis/

https://ecocostsavings.com/average-electric-car-kwh-per-mile/

Obviously an average is made up of people who drive more and people who drive less and people who need a full charge one day and little or no charge most days but it's the average of millions of people & their cars that counts for the overnight effect on the national grid. Maybe with the odd peak for bank holiday travel.

That particular piece of technology already exists.  I have a home charger which I can set to finish a charge at a specific time.  In my case, it is to make maximum use of solar power but will top up to maximum (or whatever % charge I need), using grid electric by the time I need to leave.

I dare say it’s possible to use this with off peak electric as well but I haven’t explored that particular option.  FWIW my car is happily charging off my solar panels right now and when it finishes, I have got a related device which will divert unused solar energy to my immersion heater in the hot water tank, thus saving on oil when the boiler is running.

Load balancers should be standard, they send your charger unit max power, but if you suddenly turned on the oven, kettle, electric shower etc they'll detect this and temporarily reduce power to car charger, they can be used to prioritise using power from home panels too etc... 

A bigger problem is that most households only have single phase cabling so they'll always be limited in charging capabilities. 

On most cars you can schedule when it charges, plug it in when you get home, and it starts charging at 00:30, or whenever you set it to. 

Yes and no, that average will include quite a lot of very rarely/never used cars which are still registered and roadworthy. Commuter cars will be averaging more than that while spare and toy cars will likely remain IC for years yet anyway.

I think Economy7 was to sell rather than dump excess overnight nuclear (perfect for storage heating and EVs).

The problem is quite interesting, for excessively large EV batteries (as most have) to act as virtual storage (real storage that doesn't feed back to the grid but preferentially consumes excess) on a fluctuating renewable heavy grid they need to be connected and ready to consume throughout the day (solar and wind) meaning plugging lots of them in at destination as well as at home. That needs to be incentivised because it causes some infrastructure cost and user hassle (plugs and plugging in regularly) plus it causes some unfamiliar uncertainty as to exactly how much charge your car will have when you come to it (done right the answer is always enough for predicted usage). It leaves the preventing overload task onto the supply side where it can be managed either by controlling overall supply (a blunt tool for a likely localised issues) or by signalling to networked chargers/vehicles directly. That can be by a temporally and geographically variable price signal thereby incentivising the public good of keeping cars plugged in 23/7 and allowing individuals (their onboard computers) to make decisions based on their priorities and need.

The temporal part, consuming preferentially at times of excess overall production can be handled relatively simply by the car monitoring the grid frequency, >50Hz means excess production. Geographical control of demand to prevent local network overload at times of national oversupply requires some kind of data link to the cars/chargers.

It's not a trivial problem but it is solvable and the solution brings benefits.

jk

Sure but that requires that you, we, are informed, care and are incentivised to make a good choice. Without wishing to disparage my fellow human but most of us fall short in at least one of those regards.

For an example of a perverse incentive (until solar dominates supply), I plug mine in during the day because it's free and easy, not so at home.

jk

As I reall National Grid have always seen this extra EV charging load as a non problem.   Has this changed?

##Note - 'engineers' ranting on youtube does not equal data

Depends on the destination. They're still quite useful at hotels, where you are staying overnight.

Being about 1/4 of the price is quite a strong incentive, no?

If you understand the problem and are engaged but it's not like electricity is sold by the liter, its price advertised on massive roadside screens. Early adopters come at this from a particular perspective.

jk

Just ask the guys on here how many miles they get out of a KWh of battery. Our eNV200 van at work tells me it'll do 80-90 miles on a full 40KWh charge, so your 18 mile daily usage uses 10KWh, easily replenished overnight at <1KW.  The key will be as stated upthread - how to spread that demand over the night.  There is tremendous scope for intelligent charging. For example, a Tesla powerwall is connected to the internet and downloads weather forecast data. Tell it tomorrow evening's expected demand and it'll look at the forecast and if it's going to be dull it'll fill up on cheap rate power overnight, if it's going to be sunny it'll wait for power from the solar panels in the day.  People's EVs will be used as battery storage for the grid - set an 'emergency range' plus tomorrow's expected range requirement and it will ringfence that capacity whilst running the house on the excess capacity during peak rate (saving you money) and replenish itself overnight at cheap rate. It might even be used by the grid operators for 'peak lopping' to save them spinning up a generator or powerstation for an hour at the end of eastenders. This will be a huge benefit for dealing with the electric heating problem as that relatively high load (our boiler is 14KW) is fed from within the property and not overloading the distribution network.

Maybe... but I think everyone is pretty engaged with electricity prices right now!

That's probably not unrealistic. We both use our ID3 as the primary car and on average we only charge it up a couple of times per week, and then only for a maximum of 4 hours at about 7.9kw or just over 30kwh, more often it's a bit less than that.

Your kWh/mile is a bit pessimistic for many cars. In the ID3 I've averaged 3.3miles/kwh since January, so inverting that is 0.3kwhmile, and it's far from an efficiency superstar.

The challenge is how to avoid everyone charging at once with a 7-8kw (32A) charger. Most people need that sort of charger at the moment either because they want to be able to recharge every day after a commute or/and to take decent advantage of overnight cheap periods (Octopus Go, which is only cheap for four hours from 0030 to 0430.) So at the moment a large proportion of EV charging happens in those hours of the night. If you took away all incentives, a large proportion would happen in the evening when people got home from work etc and plugged. What you need I think is incentives to charge up in certain periods, but with those periods being different for different people.

Edit to add, another solution is to limit the power draw intelligently. A lot of chargers now have the capability to detect if the total house load is approaching the fuse limit (eg 60 or 80A) and reduce power to the car on the fly. However as I understand it the grid is not usually designed for everyone to be running at or close to the fuse rating so I think this solution might need the power reductions to cut in at lower total current draws.

Octopus are also now running a tariff called Intelligent for customers with certain cars and chargers. Basically you agree to plug your car in when you get home and let Octopus decide when to charge it for you (you can specify a deadline) and in return you get some cheap power. It's all done automatically via the smart chargers internet connection. This allows Octopus to balance supply and demand better overnight at a more macro level (I don't have an understanding of how they work together with National Grid.)

Hopefully smart chargers will have an override.

As a van driver / mobile service engineer I would need to go on charge as soon as I got home incase I got called out. 

I have exactly the opposite opinion. I only rapid charge if I absolutely have to, I almost always destination charge. If the car is going to be parked anyway it might as well be charging while it's there. It doesn't take up any of my time, unlike rapid charging which will always see me waiting around somewhere where I don't want to be.

It wasn't, it was put in at a time when people plugged their Iron into the light fitting over the kitchen table and had a bar heater in the bathroom that was fed of the lighting circuit. 

Times change, things evolve. We now have induction range cookers that are fused at 80A, 12kw showers, air and ground heat pumps, but that bit of 16mm copper cable jointed onto a main cable feeding the whole street, that's not much bigger, put in the ground 70 years ago, should be fine. 

The network isn't being upgraded, no one will pay for it for a start. Access to every house is required to upgrade the LV electricity network. It takes months of organising to gain access to a farmers field to just change one pole. Imagine the organisation required to lay a new main cable down both sides of a street and then re-service every house on that street. Or change poles and re-string LV overhead wires down the street. Yes it wants doing if we are going to a fuller use of electricity, yes it can/could be done, but it's not.

The Broardband network was a completely new network when it was installed. It didn't even go into the property unless the home owner wanted it. It terminated outside the house. It caused untold damage to other utilities networks when they installed it. We are now almost at a stage where the whole electricity network needs re-newing.

In the last 5 years my street has been dug up twice, to totally replace the water and gas mains, right up to the meter in every house. They dug up my drive and made good afterwards. The electricity supply is on overhead lines, so I reckon it would be trivial to replace compared to that.

Absolutely, those poles put themselves up and the wire fixes itself to the houses. So trivial anyone could do it.

Compared to closing the road for 2 months and digging it up along with everyone's driveway I'd say replacing the poles and cable was pretty trivial. Especially since the poles must be due for replacement some time soon anyway. Two of them have fallen over since I've been here.

And upgrade the local transformer and the wires to the substation and the substation and the wire to it and .........

How necessary is that for 1kW average overnight charging per car? The only way to get a surge is if everyone in the neighborhood goes on a long drive at the same time. That doesn't happen even on a bank holiday weekend as many stay local. I can't think of any likely collective human behaviour that would prompt everyone to simultaneously deplete their batteries.