Advisability of buying electric car at this point in time

MattMattMattUK

HillStreetBlues said:

Has any research been done on all the extra weight on the roads that  the changeover will bring?

The current data is not detailed enough over an extended period of time other than to say that it will increase road wear, but as the general trend for the last 20 years has been for vehicles to get significantly heavier, especially with the rise of people driving 4x4s and SUVs on residential roads it is hard to tell. Cars were heavy, then got light, now are heavier again. The average large SUV weighs in at 2.1-2.5 tons, electric cars tend to top out at 2.5 tons and most are considerably lighter, a Model 3 is 1.7 tons and Nissan Leaf is 1.5 tons. 

A certain newspaper not known for factual accuracy and with a very obvious hatred of EVs claims that the additional weight of EVs will cause roads to fail and multi-story car parks to collapse, ignoring the fact that whilst EVs are heavier than cars as an average, for comparable size vehicles they are only slightly heavier, they just tend to be at the larger end at the moment. As an example the Model 3 and 3 Series are regarded as being in the same segment and depending are within a few KG of each other, the same across the range of vehicles. The reason that the average weight of EVs is higher is at the moment there are hardly any compact/ultra-compact models on the market, together with the additional weight from enhanced safety built into the structure. 

Martyn1981

Goudy said:

Yes but a Tesla isn't 44 tonnes.

At the moment, battery HGV's have a very limited range, around 160 to 200km when loaded and require far far more batteries then your average Tesla, often four 112kw or larger batteries due to their weight, which take longer to charge.

As they are limited to 56 mph (90 kph) you are looking at a working time of around 2 hours of less with a lengthy break for the recharge at least four 112kw batteries.

Currently a HGV driver is limited to around 4.5 hours driving with a 45 minute break.
So your EV truck will go half the distance and require the driver to have more and far longer breaks.
Anything it is carrying is just going to shoot up in price.
I made the statement we are all going to pay, yes we are. 

Hydrogen is widely used by TFL on their buses and is being used in HGVs already.
It's used in shipping and other industries as a power source and yes even cars. I see hydrogen powered mini cabs everyday on the streets of London.

At the moment there are 16 hydrogen fuel station dotted around the country, up from 12 last year. It might be difficult to handle but it is being handled and distributed, there's no doubt about that.

I understand how hydrogen is produced but with the investment in green electricity (which we currently turn off when no one needs the power from it), it can be produced greenly.
Ok, a fuel cell will require a battery but nothing like the scale of batteries needed for battery cars and HGVs.

As that BBC programme explained, we are massively behind in scaling up production of the raw materials for batteries and it takes years to actually scale up.

We wouldn't be totally reliant on storing power in materials of limited availability, controlled by dubious governments.
We've been there and it never goes well for us.

I see it a more viable approach for energy security than what is happening at the moment but of course there might be others, yet to be explored. 
I am convinced the battery is today, but it's certainly not for tomorrow.

Hi, not sure about your maths. The US max weight is 80,000lbs, or 82,000lbs for a BEV, so the Tesla semi can haul about 37tn. But of course, with about 2x the power of a diesel, and delivered instantly, it has no problem with pulling more.

As mgfvvc refernces, one recently completed a 500 mile trip at 81,000lbs, it used ~93% of battery capacity (starting at 97% and ending at 4%). So that's about 871km v's the 160km to 200km you stated.

In the EU, the max weight for a BEV HGV is +2tn, so 46tn. But note that energy density of batteries, both the Wh/l and Wh/kg are still improving fast. Common today are 240Wh/kg, but 400Wh/kg (even 700Wh/kg) exist, but just cost more, so will work their way into use as costs continue to fall.

Those extra weight allowances will help to offset the higher vehicle weight (from batts), but I believe the lighter 300 mile Tesla semi version, will have roughly the same carrying load as a normal diesel. Also worth noting that the majority of trips in the US and Europe and less than 500 miles, and about 85% of loads are max volume, not max weight.

Tesla quote a 70% charge rate in 30 mins, to go with the mandatory breaks in the US and Europe. Your 4.5hr figure if driven at the UK max, would be ~270 miles, but a 70% charge would be about 350 miles.

You say the costs of goods will go up, but the lower running costs of a BEV truck, v's an ICE per mile, should actually mean the very opposite. Plus of course the massive gains for emissions and air pollution.


Regarding H2, that's pretty much a bust flush now, and being dropped by many. London closed two H2 stations this year. The vehicles still need a large battery, plus very heavy H2 tanks, weighing about 100kg each. Just the 'small' Hyundai rigid HFCV has seven of those.

But the biggest problem(s) with H2 is the simply staggering amount of renewable leccy we would need to make the green H2, about 3 times more than for BEV's. And how we transport it, since it's not very energy dense, so even a max weight H2 tube trailer truck (44tn) only carries about 500kg of H2. That's only enough for ~15 of those smaller Hyundai trucks. There have also been quite a few H2 explosions, including one a few days ago, but this may just be an issue that will pass as we get better at dealing with H2.

Some graphics to help:

WellKnownSid

mark_cycling00 said:

Still the issue of whether we have enough electricity for all these cars. 

The grid has ample supply.  5% of that required to power an entire electrified UK vehicle fleet could come from the electricity we currently pay wind farms in Scotland to throw away right now.

There will be significant challenges getting it all to the right places - it's tough to plug in when you're on the 21st floor.  These things will be overcome.  V2G and other technologies may help grid balancing.

Car manufacturers were clear that it was impossible to electrify the UK by 2040... inevitably when the Government held a gun to their head and told them it was 2030 we're already seeing 17% market share and growing, which is the classic 'point of no return' on the yield curve.

I have a friend who stocked up on 60 and 100 watt light bulbs a few years ago because the EU was banning them.  Good for them, the rest of us moved on...

Petriix

mark_cycling00 said:

Still the issue of whether we have enough electricity for all these cars. 

That's not actually an issue as National Grid themselves confirmed... 

Even if we all switched to EVs overnight, we believe demand would only increase by around 10%. So we’d still be using less power as a nation than we did in 2002 and this is well within the range of manageable load fluctuation.

Martyn1981

MattMattMattUK said:

HillStreetBlues said:

Has any research been done on all the extra weight on the roads that  the changeover will bring?

The current data is not detailed enough over an extended period of time other than to say that it will increase road wear, but as the general trend for the last 20 years has been for vehicles to get significantly heavier, especially with the rise of people driving 4x4s and SUVs on residential roads it is hard to tell. Cars were heavy, then got light, now are heavier again. The average large SUV weighs in at 2.1-2.5 tons, electric cars tend to top out at 2.5 tons and most are considerably lighter, a Model 3 is 1.7 tons and Nissan Leaf is 1.5 tons. 

A certain newspaper not known for factual accuracy and with a very obvious hatred of EVs claims that the additional weight of EVs will cause roads to fail and multi-story car parks to collapse, ignoring the fact that whilst EVs are heavier than cars as an average, for comparable size vehicles they are only slightly heavier, they just tend to be at the larger end at the moment. As an example the Model 3 and 3 Series are regarded as being in the same segment and depending are within a few KG of each other, the same across the range of vehicles. The reason that the average weight of EVs is higher is at the moment there are hardly any compact/ultra-compact models on the market, together with the additional weight from enhanced safety built into the structure. 

Funny you should say that. I popped to my sister's last friday. They have a small holding, and are keen to be ever greener. They plan to get a SH BEV next, but a few years away. She mentioned that the news was full of negative BEV stories, and mentioned the 'collapsing multi-storey car park' comments going around.

So, I suggested that a multi-storey is probably constructed to withstand the weight of the heaviest vehicle in each space, rather than an average, since you have to plan for the worst. I may be wrong, but that seems sensible.

Next we looked up the weight of our cars. Now, they aren't exact matches, I appreciate, but my LR Tesla Y weighs in at 1,930kg. So we looked up her Land Rover LR2, and it was 4,255lbs, which (fun surprise and shock to us both) is 1,930kg.

Also looked up what the big Range Rovers weigh, and they seem, depending on model, to weigh in at around 2.3tn to 2.8tn.


Also, technology is improving, and a fun factoid from some years ago, is that when Renault increased the Zoe battery pack from 22kWh to 41kWh (+86%), the 'larger' battery pack was actually the same size, whilst the weight went up from 275kg to 305kg (+11%).

Ectophile

While the National Grid are happy that they have enough capacity, it's the local power networks that are going to be the problem.  Particularly that last few hundred yards from your local transformer to your home.

For many years, it's been assumed that a house that isn't heated by electricity will use about 2kW when averaged over a day.  So if you're building an estate of 100 houses, all with gas boilers, then you need 200kW of transformers to supply the estate.

But an electric car on a home charger can draw 7kW for several hours.  And it will be even worse when gas boilers are banned and we start switching to electrically powered heat pumps.

But the DNOs (District Network Operators) are doing what privatised utilities usually do: nothing, until something goes wrong.  Then they patch things up when they break.

WellKnownSid

Ectophile said:

For many years, it's been assumed that a house that isn't heated by electricity will use about 2kW when averaged over a day.  So if you're building an estate of 100 houses, all with gas boilers, then you need 200kW of transformers to supply the estate.

Kind of feels wrong.

We have a 150kVA transformer across two poles - which feeds five houses and a farm.  Can't say I've ever noticed something that small feeding an estate of 75 homes...  I'm not saying corners aren't cut in the world of UK housing estate development of course.

I can imagine this in rural Spain or Italy - I used to live in a place which still had its original 1kVA supply.  Four amps of raw power.  We blew the Iberdrola fuse by plugging in our UK kettle...

CKhalvashi

Ectophile said:

While the National Grid are happy that they have enough capacity, it's the local power networks that are going to be the problem.  Particularly that last few hundred yards from your local transformer to your home.

For many years, it's been assumed that a house that isn't heated by electricity will use about 2kW when averaged over a day.  So if you're building an estate of 100 houses, all with gas boilers, then you need 200kW of transformers to supply the estate.

But an electric car on a home charger can draw 7kW for several hours.  And it will be even worse when gas boilers are banned and we start switching to electrically powered heat pumps.

But the DNOs (District Network Operators) are doing what privatised utilities usually do: nothing, until something goes wrong.  Then they patch things up when they break.

ETA: @Martyn1981 has once again explained it so much better than I could ever below.

 Yes, but my Ioniq for example has 180-200 miles of range. The car averages about 90 miles a day, so it's not charged every day at home, probably at the moment twice a week on average (I have access to free charging in the supermarket for a few hours and also access to charging at our office/client sites on occasion). OH also charges her car about twice a week at home, but has something with a bigger battery pack and drives a bit less). The cars between them do around 60k miles a year. Most households don't do this mileage.

So, 7kW would be for 4 homes with 1kW left, it takes around 5 hours to charge at worst case every other night. I have no idea how much electricity our fridge uses, but that, the clock on the cooker and a phone charger are generally the only things plugged in when the car is charging. If they average under 250W, everything is good with the world. Some homes won't drive, night workers will need to charge in the day, etc etc etc.

For most drivers, that Ioniq with quite a small (38kWh) battery pack is absolutely fine. When we took it to Poland it was frustrating due to a low-ish rapid charging capacity. For the probably once a year that journey would ever be remotely necessary to drive, the Enyaq should cover it in a far more efficient manner (time-wise). Electricity-wise it's probably about 25% less efficient but we haven't really had chance to test it yet.

Martyn1981

Ectophile said:

While the National Grid are happy that they have enough capacity, it's the local power networks that are going to be the problem.  Particularly that last few hundred yards from your local transformer to your home.

For many years, it's been assumed that a house that isn't heated by electricity will use about 2kW when averaged over a day.  So if you're building an estate of 100 houses, all with gas boilers, then you need 200kW of transformers to supply the estate.

But an electric car on a home charger can draw 7kW for several hours.  And it will be even worse when gas boilers are banned and we start switching to electrically powered heat pumps.

But the DNOs (District Network Operators) are doing what privatised utilities usually do: nothing, until something goes wrong.  Then they patch things up when they break.

I don't think that's correct. The existing set up is capable of providing enough power for power showers (7-10kW), or for electric space heating via resistive heating*. So they can manage high continuous load already. Homes will have 60A - 100A main fuses, which equates to about 14kW to 23kW.

For car charging you can apply averaging, as the number and distribution of BEV's will be so high. So let's work on 30m cars across 25m residences (or nearby chargers such as street chargers), so that's 1.2 BEV's per property.

Next let's assume 3 miles per kWh, and an average daily trip of 22 miles (UK driving average is now less than 8,000miles per annum, or 22/day). So that's 7.33kWh, and we'll concentrate that into a 12hr period 8pm to 8am, so an additional household demand of :

0.61kW (22miles / 3m/kWh) x 1.2 vehicles = 0.73kW.

Or if concentrated over 7hrs of cheap rate, then it's 1.26kW.

[Note - 3m per kWh average may seem quite low, especially as we get more smaller lighter BEV's doing mainly slow city driving. Our long term average with a 28kWh IONIQ is 4.7m/kWh. But let's go with worst case winter ranges and the losses (~5 to 10%) during charging.]

Space heating is almost certainly going to be a bigger issue, but even then the average size of a domestic heat pump will be 5kW to 16kW, but those are the rated heat output numbers, the consumption (input) is roughly one quarter of that, so much lower than a power shower.

But I do agree that the UK DNO's need to be more pro-active. Some new estates, when thinking ahead, are actually installing 3phase leccy as standard. But, ironically, this isn't due to the slow and steady demand for ASHP's and BEV's charged overnight, but to allow for upto 22kW BEV charging on demand, if homes choose to install such a charger and use it. [Note, even with some users charging at a faster rate, the averaging still applies.]

*I mention electric resistive space heating (eg storage heaters), as they will be approx 100% efficient, but the annual average efficiency for ASHP (air source heat pumps) is a COP of ~2.9, or slightly confusing, but 290%. So demand (both power (kW) and energy (kWh)) from those properties will actually fall. As will the demand for hot water tanks if heated from leccy, when heated via the main ASHP, or simply replaced with a HPHW tank (heat pump hot water).

Goudy

My maths was based on a currently available BEV HGV tractor unit and not something that isn't yet available.

The eActros 300 from Mercedes has a range of around 330km on a full charge.
It can charge from 20% to 80% in 90 minutes on a 160kw charger.

So 90 minutes for 60% charge is around 200km, but to be fair we can to add some of the retaining 20% which obviously needs replacing at a later recharge which would take even longer on a charger.

Current regs for HGVs aren't simple, but it's around 4.5 hours with a 15 minute break (4.5 x 56 mph is 252 miles max range) but with the current crop of BEV HGVs, we're now on 3.5 hours with a 90 minute break for only 196 miles.

Fuel isn't the only factor when costing out road freight like this.
There's obviously the cost of the equipment and the drivers time to consider. 

The current UK weight limit for a 6 axle HGV is 44000kg.
The US limit is nearly 20% less at 36000kg, but that depends on what state it's in, some are actually lower than that.
Would the yet to be available Tesla Semi's range reduce by 20% with 20% more weight, no.

BEV become less and less efficient the heavier they get but the Tesla Semi would have to have at least 20% better range for a similar load than what's on the market now and charge much much faster, even when you factor in the fuel cost savings.

BTW, the Toyota Mirai's (hydrogen car) battery is only 1.2 kw. Hardly large, it's similar to most hybrids.
What's the size of a Tesla battery, 50, 60 or more kw?