Will Electric Vehicles Be Viable? When?

[Ferry]

Any member here currently operating a electric car in sub-zero ambient temps?

I do! this is my 6th winter with a BMW i3. 130.000 km so far. The range loss is about 30% on the worst winter day, compared to a good summer day. 250 km summer, 180 km winter, or thereabouts. In my experience the worst conditions are wet roads with slushy ice, around 0 deg. C. High rolling resistance and pretty high consumption for heating. Colder weather obviously takes more heating, but the roads have less rolling resistance with hard frozen ice. Luckily you can't have slushy ice and very low temperatures at the same time. -12 to -15 is pretty normal mid winter, but on average more like -5 C. The coldest I've driven in was -24 C.
Pre heating helps the range a bit, and the comfort a lot. When connected to the wall charger the battery is heated to +10 C. Heating/cooling of the cabin can be done without connection to the charger. Takes a few % of the battery, but no big deal. Best part is I can start it from my phone, or a PC. No more cold starts, frozen windows etc.
It's the best winter car I've owned. Traction control and ESP is superb. Downside is lower range and slower fast charging with a cold battery.
Another thing I really like with the i3 is the materials used. With cold climate comes also road salt and heavy corrosion. The i3 is made mainly of carbon fibre, plastic and aluminium. So problems with corrosion should be non, or at least much less. Time will tell, I guess. And for a racing fan to have a car made of carbon fibre... well, that's cool!

[J.A.W.]

^ Excellent reply, most informative, ta for that, Ferry.

[Greg Locock]

The aluminium/air battery is not quite what you'd hope. basically they are oxidising the aluminium and then sending the aluminium oxide back to a factory to get reduced again.

from wiki

Aluminium–air batteries are primary cells, i.e., non-rechargeable. Once the aluminium anode is consumed by its reaction with atmospheric oxygen at a cathode immersed in a water-based electrolyte to form hydrated aluminium oxide, the battery will no longer produce electricity. However, it is possible to mechanically recharge the battery with new aluminium anodes made from recycling the hydrated aluminium oxide. Such recycling would be essential if aluminium–air batteries are to be widely adopted.

[rscsr]

The aluminium/air battery is not quite what you'd hope. basically they are oxidising the aluminium and then sending the aluminium oxide back to a factory to get reduced again.

from wiki

Aluminium–air batteries are primary cells, i.e., non-rechargeable. Once the aluminium anode is consumed by its reaction with atmospheric oxygen at a cathode immersed in a water-based electrolyte to form hydrated aluminium oxide, the battery will no longer produce electricity. However, it is possible to mechanically recharge the battery with new aluminium anodes made from recycling the hydrated aluminium oxide. Such recycling would be essential if aluminium–air batteries are to be widely adopted.

And the "recharging" seems to be not really efficient. From the data I've found you are looking at about 10%.
But for high performance applications, like racing and flying, it would be fine imho.

[henry]

A friend and I have similar usage patterns for our cars.

One is a Tesla Model S 85kW the other a VW Golf 2.0 TDi

For the Golf the CO2 can be calculated from the diesel consumed, distance traveled. Tank full to full it’s typically 52 litres for 580 miles. 240g/mile. ( around 50mpukg, 40mpusgallon, 5.7 l/km)

For the Tesla it’s a little more complicated

85kWh gives a range of 230 miles. This requires 92kW of generated electricity to allow for distribution losses, around 8% in the U.K. Consumption is 0.4kWh/mile

Assuming the Tesla is charged at random times across the year the CO2 per kWh will match that coming from the U.K. generation mix over the same period. I chose Q3 2018 to Q2 2019 as the latest provided by OFGEN. I used CO2 levels from an analysis of lifecycle studies round the world from this document: http://www.world-nuclear.org/uploadedFi ... cycle.pdfy

Using this figures the Tesla creates 88g/mile CO2

I also looked at some single source figures.

Coal 355
Gas 200
Wind 10

interestingly the U.K. government rates the Golf at 138g/mile, but even then there are savings to be made by going electric in the U.K. Particularly by charging at night when the CO2/GWh drops.

[subcritical71]

A friend and I have similar usage patterns for our cars.

One is a Tesla Model S 85kW the other a VW Golf 2.0 TDi

For the Golf the CO2 can be calculated from the diesel consumed, distance traveled. Tank full to full it’s typically 52 litres for 580 miles. 240g/mile. ( around 50mpukg, 40mpusgallon, 5.7 l/km)

For the Tesla it’s a little more complicated

85kWh gives a range of 230 miles. This requires 92kW of generated electricity to allow for distribution losses, around 8% in the U.K. Consumption is 0.4kWh/mile

Assuming the Tesla is charged at random times across the year the CO2 per kWh will match that coming from the U.K. generation mix over the same period. I chose Q3 2018 to Q2 2019 as the latest provided by OFGEN. I used CO2 levels from an analysis of lifecycle studies round the world from this document: http://www.world-nuclear.org/uploadedFi ... cycle.pdfy

Using this figures the Tesla creates 88g/mile CO2

I also looked at some single source figures.

Coal 355
Gas 200
Wind 10

interestingly the U.K. government rates the Golf at 138g/mile, but even then there are savings to be made by going electric in the U.K. Particularly by charging at night when the CO2/GWh drops.

Henry, why do you take the transmission and distribution of energy into account for the Tesla but not the Golf? Or is that what the 240g/mile figure is showing?

[Greg Locock]

Typical well to fuel tank losses are 17%

[J.A.W.]

Typical well to fuel tank losses are 17%

What efficiency loss-figure appends to fuel/thermal & fuel/gas-turbine electric plant supply-to-charge?

[Andres125sx]

A friend and I have similar usage patterns for our cars.

One is a Tesla Model S 85kW the other a VW Golf 2.0 TDi

For the Golf the CO2 can be calculated from the diesel consumed, distance traveled. Tank full to full it’s typically 52 litres for 580 miles. 240g/mile. ( around 50mpukg, 40mpusgallon, 5.7 l/km)

For the Tesla it’s a little more complicated

85kWh gives a range of 230 miles. This requires 92kW of generated electricity to allow for distribution losses, around 8% in the U.K. Consumption is 0.4kWh/mile

Assuming the Tesla is charged at random times across the year the CO2 per kWh will match that coming from the U.K. generation mix over the same period. I chose Q3 2018 to Q2 2019 as the latest provided by OFGEN. I used CO2 levels from an analysis of lifecycle studies round the world from this document: http://www.world-nuclear.org/uploadedFi ... cycle.pdfy

Using this figures the Tesla creates 88g/mile CO2

I also looked at some single source figures.

Coal 355
Gas 200
Wind 10

interestingly the U.K. government rates the Golf at 138g/mile, but even then there are savings to be made by going electric in the U.K. Particularly by charging at night when the CO2/GWh drops.

So just a third, with a 63% of emissions saving

And that is today, year by year the Golf will slightly increase its consumption and emissions (an old engine does not run as smooth as a new one due to increasing play of moving parts, acummulated cinder, etc.), while the Tesla will slightily decrease theirs, as each year electricity has a bigger percentage of renewables, reducing emissions per MWh of electricity, and emissions per km/mile, making that big difference even bigger year by year

But some people still doubt about the path to take

[henry]

A friend and I have similar usage patterns for our cars.

One is a Tesla Model S 85kW the other a VW Golf 2.0 TDi

Henry, why do you take the transmission and distribution of energy into account for the Tesla but not the Golf? Or is that what the 240g/mile figure is showing?

Partly laziness, partly not wanting to be too contentious.

I started calculating with the Tesla, so I had a comparison figure. When the Golf tailpipe figure came out so high I stopped. I did briefly try to estimate the diesel distribution CO2 but it only came out at 1 or 2 grams so well within the “accuracy” range for the other variables.

Speaking of the range of variables: I calculated the diesel CO2 from a basis of burning 1 litre emits 2.6 kg of CO2. Since posting I’ve found values ranging from 2.4 to 2.7 depending on the carbon content and density. Quite a big spread.

I’m quite nervous of those figures. As a non chemist I’m surprised that burning around 0.75 kg of carbon would result in 2.5kg of CO2. But even if the resulting CO2 were 1 kg the Tesla would produce less than the Golf in the U.K.

Right now there is low demand and quite a lot of wind. Current generation is producing 113 g/kwhr* and the Tesla charged now would be down to around 45g/mile. As @andres125x points out, as renewable percentage goes up the Tesla CO2 output goes down.

* this value comes from Ecotricity’s website. I don’t know exactly how they calculate it.

There is a source that uses the same emission parameters I used, gridwatch.co.uk, but I’d need to number crunch to get the g/kWhr number. I’ll compare them when I get a moment. They both report renewables at around 50% of demand.

[Just_a_fan]

I’m quite nervous of those figures. As a non chemist I’m surprised that burning around 0.75 kg of carbon would result in 2.5kg of CO2. But even if the resulting CO2 were 1 kg the Tesla would produce less than the Golf in the U.K.

Rough and ready: C=12, O=16. So 12/(12+16+16) = 0.273. Weight of carbon is 27% of the weight of CO2 = 0.68kg C in 2.5kg of CO2.

[henry]

I’m quite nervous of those figures. As a non chemist I’m surprised that burning around 0.75 kg of carbon would result in 2.5kg of CO2. But even if the resulting CO2 were 1 kg the Tesla would produce less than the Golf in the U.K.

Rough and ready: C=12, O=16. So 12/(12+16+16) = 0.273. Weight of carbon is 27% of the weight of CO2 = 0.68kg C in 2.5kg of CO2.

Thanks. Very clear.

I’ve seen similar, not as clear, but worried that they might be a misconstruction being propagated round the internet by the unscrupulous. Such is the level of paranoia I’ve been driven to.

[henry]

I compared Ecotricity and Gridwatch. They are roughly in synch. Gridwatch shows demand and so includes feeds from interconnects, France, Netherlands, others, Ecotricity just shows U.K. generation. Using Ecotricity’s easy to access number will underestimate CO2 g/mile by up to 20% compared with Gridwatch.

[Greg Locock]

What efficiency loss-figure appends to fuel/thermal & fuel/gas-turbine electric plant supply-to-charge?

I guessed that Henry's figure included that.

Losses in the grid vary wildly. Best case power station-> customer in some American states is 3%, worst case I know of is remote wind or solar farms in Oz, 20%, and due to the idiocy of our lords and masters, guess who pays for that? Not the solar farm operator.

[J.A.W.]

Ok, ta for that Greg.

Here is Kevin Cameron's recent consideration of the figures appending to an all-electric
personal transport fleet take-up in the USA, with generation/transmission requirements:

https://www.cycleworld.com/story/bikes/ ... -electric/