Electric cars

zeupater

Joe_Horner wrote: »

Incidentally, just a couple of fun facts to lighten the mood.

Petrol and diesel have around 7 times more energy per kg than dynamite.

Dried cow or camel dung has around 20 times more energy per kg than current Tesla batteries.

Hi

Same issue, you need to efficiently convert the camel dung, dynamite or petroleum to traction energy ... also, if you take a conservative 1000 cycle equivalent for battery recharging lifespan it becomes (20*.3) vs (1x1000) resulting in the Tesla battery having a around 170 times the overall deliverable energy density of the camel dung, that's quite a manure heap you'd need! ... but then again, 1000cycle equivalent is also quite conservative ... :cool:

HTH
Z

Joe_Horner

zeupater wrote: »

Hi

Whatever you're attempting to convey & however you're calculating for comparison, you need to make allowance for two major elements ... the relative traction delivery efficiency -and- the embedded energy from the refining process needs to be netted off ... you simply can't compare the total combustible energy potential of a volume of refined fuel with the traction energy potential of stored electricity - To make a direct comparison it must be total energy to create traction vs total energy to create traction

HTH
Z

No I don't, because I'm not making a comparison between electric and anything else. so there's no conversion or factoring required.

Look:

If we (very generously) allow that all electric cars, under all conditions, can achieve a 400 mile range on a 100kWh charge then that means that they will travel 4 miles of every 1 kWh of charge they receive from the grid - that is, for every 1 kWh of energy actually delivered at the point of charging

If we (generously) allow that all LGVs, under all conditions, can achieve 300 miles on a 100kWh charge then that means that LGs will travel 3 miles for every kWh of charge they receive from the grid.

If we (absurdly generously) assume that all electric HGVs and busses, under all conditions (including fully loaded) can achieve a 200 mile range on a 100kWh charge then that means that they will travel 2 miles for every 1 kWh of charge they receive from the grid.


Total car / cab mileage in 2016 was estimated at 252 billion miles. At 4 miles per kWh of charge they receive, that means they must receive, at the point(s) of charging, 63 billion kWh because 252 billion miles divided by 4 miles per kWh = 63 billion kWh.

Total LGV mileage in 2016 was estimated as 49 billion miles. At 3 miles per kWh of charge received that means they must receive 16.3kWh to cover those miles

Total HGV and bus mileage in 2016 was estimated at 19.2 billion miles. At 2 miles per kWh of charge received, that means they must receive 9.6 billion kWh to cover those miles.



So, to meet 2016 use of the entire fleet would need (63 + 16.3 + 9.6) billion kWh = 88.9tWh of electrical energy delivered to the vehicles' batteries at the charging points

Joe_Horner

zeupater wrote: »

Hi

Same issue, you need to efficiently convert the camel dung, dynamite or petroleum to traction energy ... also, if you take a conservative 1000 cycle equivalent for battery recharging lifespan it becomes (20*.3) vs (1x1000) resulting in the Tesla battery having a around 170 times the overall deliverable energy density of the camel dung, that's quite a manure heap you'd need! ... but then again, 1000cycle equivalent is also quite conservative ... :cool:

HTH
Z

Nah, you just set fire to all of them and see which makes the best bang,film it and start a sponsored youtube channel, then buy whatever transport you like with the ad revenue.

I must admit, in that test my money is on the tesla battery - have you seen how LiPo cells burn?

:beer:

zeupater

Joe_Horner wrote: »

No I don't, because I'm not making a comparison between electric and anything else. so there's no conversion or factoring required.
....

So, to meet 2016 use of the entire fleet would need (63 + 16.3 + 9.6) billion kWh = 88.9tWh of electrical energy delivered to the vehicles' batteries at the charging points

Hi

Your entire premise for all of these calculations is to 'prove' that a mass roll-out of EVs is effectively impossible because of the limitations of existing and/or future infrastructure ... for example ..

Joe_Horner wrote: »

They'll be needed to supply all those power stations we have to build in a hurry..

... accepted that's a point made in jest, but it certainly supports your view, therefore everything you have mentioned has been done to describe & compare the scale of what needs to be done ...

... now to the "88.9tWh of electrical energy delivered to the vehicles' batteries at the charging points" ... as continually raised, you are talking cross-purposes, delivery demand is not the same as supply generation because you need to offset the refining energy for the volume of fuel needed to create the equivalent level of traction energy ...

Anyway, 88.9TWh/year is huge, it's 88,900,000MWh, take off the 6kWh of electricity for refining 14kWh of traction energy and if there was no spare generation at any time we'd need an additional 51TWh of capacity, over 24,000,000 UK households that's 2.1MWh/household/year ... wait a minute, that's significantly less than we currently export in a year from the 4kWp of solar panels on our roof .... maybe it's not that much after-all ... :cool:

HTH
Z

Joe_Horner

zeupater wrote: »

Hi


... now to the "88.9tWh of electrical energy delivered to the vehicles' batteries at the charging points" ... as continually raised, you are talking cross-purposes, delivery demand is not the same as supply generation because you need to offset the refining energy for the volume of fuel needed to create the equivalent level of traction energy ...

Anyway, 88.9TWh/year is huge, it's 88,900,000MWh, take off the 6kWh of electricity for refining 14kWh of traction energy and if there was no spare generation at any time we'd need an additional 51TWh of capacity, over 24,000,000 UK households that's 2.1MWh/household/year ... wait a minute, that's significantly less than we currently export in a year from the 4kWp of solar panels on our roof .... maybe it's not that much after-all ... :cool:

HTH
Z

I'm really not sure if you're intentionally not understanding of if it's a real block / my poor explanation skills.

I'm talking entirely about energy at the same point in the cycle - delivery to the customer. That's the power that would be registered on your electricity meter and all the factors you keep introducing have already happened at that point.

If your meter shows that you've used, say, 100kWh this month then that's what you've used and that's what you get billed for. the fact that 100kWh may have used 200kWh of energy input at the power station doesn't matter - you have used 100 kWh of energy.

Similarly, if you top up your electric vehicle by 1 kWh then you have used 1 kWh of elecH (using the figures I've allowed) will carry you 4 miles before you need to top up again. the amount of energy input at the power station is irrelevant - you've used 1kWh on your meter and you've traveled 4 miles.

If you insist on calculating back to the energy input at the power station, then all the losses you keep trying to take away must be added to that 1kWh in order to see how much energy is input to get that 1kWh out.

Now:

• The energy taken OUT of the system (ie: after losses) for 2016 fleet mileage would be 88.9tWh.
  
• The total energy OUTPUT by the UK electricity supply (ie: after losses) in 2016 was about 303tWh according to DECC estimates.
  
• The OUTPUT energy for all-electric transport on 2016 mileage would be about a 30% addition to the total OUTPUT of the system in 2016

Both of those figures may well need double (or more) energy INPUT to the system (ie: at a different point in the supply system) but that's not relevant to the comparison because all figures are for energy OUTPUT - ie: at the SAME POINT in the system.

Martyn1981

Joe_Horner wrote: »

Err, the energy lost "through inefficiency" IS PART OF THE LOSS. That's what inefficiency means[i/] !!!!!!!!! You can't just pick the part of the energy cycle that suits you and say "Look!!! 100% efficient!!!!" because that's cheating*.

It's also a strawman suggesting that I declared them as "distribution losses" when I very clearly stated "generation and distribution losses".

What you 'proved' is that the amount of raw energy that goes into electricity production is far greater than the energy that comes out. That's absolutely true, and reflects the inefficiencies of burning FF's.

What you also proved confirmed therefore, is that doing the same with small ICE engines is also incredibly inefficient.

In fact whilst a gas generation plant can have an efficiency of 50%, petrol and diesel 'real' efficiency is about 20%-35%.

And that's the efficiency of burning petrol and diesel, so after the energy losses of converting from raw crude.

So as we rapidly move towards zero coal, and about 45%-50% leccy generation from gas, we see that 'moving' transport from half FF's (at 50%) is far better than all cars on FF's at about half the conversion efficiency.

Martyn1981

Joe_Horner wrote: »

So, to meet 2016 use of the entire fleet would need (63 + 16.3 + 9.6) billion kWh = 88.9tWh of electrical energy delivered to the vehicles' batteries at the charging points

Do you think that's a problem? Renewables generate that much, and the vast majority has been installed in the last 10yrs.

There is absolutely no problem whatsoever in adding that much generating output to the UK in the next 20yrs plus, and the CO2 savings of removing FF cars from the road, is actually far greater than the CO2 savings of pushing more gas off the leccy grid.

AnotherJoe

IanMSpencer wrote: »

If households are charging their 2 (or more) cars and with larger ranges charging for longer or faster, then I'd want the National Grid official view on whether the infrastructure is designed to cope with the change in load. We did have an XMas afternoon power cut for example.

The National Grid did actually do a report on this, the TL;DR version is that overall the infrastructure is fine and that local upgrades that are no big deal will be needed and can be implemented over time as part of routine maintenance.

To take your xmas afternoon power cut as an example, if that was caused by useage now, then your local infrastructure needs an upgrade anyway, so as long as that takes into account future needs such as increased car charging the incremental cost for cars will be trivial.

I can recall electric lamps being installed in my street when I was a kid, and though I wasn’t reading the newspapers then I doubt there were many people saying “we can’t have new fangled electric street lighting because our electricity infrastructure isn’t up to it” they just got on with it an upgraded. Same I suppose as no one said “you can’t have petrol cars because that would involve installing a massive infrastructure of petrol stations and petrol distribution”

Joe_Horner

Martyn1981 wrote: »

Do you think that's a problem? Renewables generate that much, and the vast majority has been installed in the last 10yrs.

There is absolutely no problem whatsoever in adding that much generating output to the UK in the next 20yrs plus, and the CO2 savings of removing FF cars from the road, is actually far greater than the CO2 savings of pushing more gas off the leccy grid.

Are you for real?

It's "no problem" increasing the UK'so electricity supply by nearly 1/3? Remember, it needs to be generated and distributed and to avoid problems that has to be based on peak demand.

EV charging is likely to (broadly) follow current peaks as people get home and plug their cars in but can probably be spread a little off peak by enforced timing (nothe much good if you need your discharged car before your allotted charging slot...), or hefty premium billing for on-peak charging to encourage people to self-regulate. So let's say that the 30% increase in total demand only gives a 20% increase in peak.

In 2005 / 6 (the most recent figures I can find) the peak demand on the national grid (ie: distribution capacity) was about 81%. Add 20% to that and you're running the grid at over 97% of it'so maximum capacity. And that assumes that the demand is perfectly spread according to local capacities, which it will never be.

So we need more generating AND more pylons - and, regardless of need, people don't like pylons unless they're on someone else's skyline!

AdrianC

The transformer for our little throng of 8-9 houses and a small farm lives up a pole behind my garage, fed by three 11kV lines strung across fields. They go nowhere after us.

When the garage was built, three years ago, Western Power took a precautionary look at the transformer, and decided to replace it while they could do so easily. They took the old 200A-fused single-phase transformer down, with its poles - untouched since it was put up when AC first came here in the 1960s - and replaced it... with a 200A-fused single-phase transformer.

"Why nothing bigger? Why not three-phase, since all three come across?"
Ah, that's because the local infrastructure is really, really pushed and clinging on by the skin of its teeth. They don't want to risk upgrading any one bit, no matter how minor, for fear of the knock-ons...