Are we on the brink of an electric car revolution?

Our transport is heavily oil-based. What are the alternatives?

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adam2
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Post by adam2 »

cubes wrote:
Little John wrote:Electric cars are, indirectly, for the vast majority of their fuel needs, FF cars and this will continue to be the case. Electricity does not come from the electricity fairy. What electrical power that is currently generated via renewables is only sufficient to meet a fraction of domestic residential usage.
Are FF powerplants more or less efficient than ICEs?
Both vary a lot, but in general power plants are considerably more efficient than vehicle engines.
CCGT plant is up to 50% efficient under typical working conditions and has reached 55% under ideal conditions. Such plant makes up the great majority of UK FF generation so this figure is the most important one.
Smaller contributions are made by coal at about 35% efficiency, and by OCGT and diesel at about 30% efficiency.

Petrol engines used in cars are often about 20% efficient under ideal conditions, but less than half that in practical use.
Diesel engines as used in vehicles are often about 25% efficient under ideal conditions, but again half or less of that in normal use.
The efficiency of a vehicle engine when idling at traffic lights or in a jam is in effect zero.
As a very approximate guide, power plants are about 3 times as efficient as ICEs in vehicles.
Most power plants burn natural gas, a fuel not ideal for road vehicles.
A small and falling percentage of electricity is from coal, completely unsuitable for modern vehicles.
An even smaller percentage is from oil, which could be burnt in vehicles.
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Post by fuzzy »

It also needs mentioning that the 80% 'waste' in an ICE vehicle is what is keeping you warm and de-misting your screen Nov to April
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Post by PS_RalphW »

I have not seen figures but the leaf uses a relatively efficient air con unit for both heating and cooling. According to the nissan website I only use less than 10% on peripherals and heating. The cars is cold in winter!
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Post by clv101 »

https://www.carbonbrief.org/analysis-sw ... wer-demand

This article runs the numbers on EV emissions and power generation.
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Post by Pepperman »

Also most EVs can be pre-conditioned, i.e. brought up to temperature just before you need them and while still plugged in. It won't take that much energy to maintain that temperature over a typical commute. But on longer journeys heaters do take a toll on EV range.

I'm sure I saw some data on temperature effects from one of the UK EV trials but I can't remember which one it was....

ETA: Ah here's one from 2014:

http://www.cenex.co.uk/wp-content/uploa ... report.pdf

I guess a kW or two of heat is relatively small beer up against tens of kW of motor power needed to drive the car.
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Post by vtsnowedin »

fuzzy wrote:It also needs mentioning that the 80% 'waste' in an ICE vehicle is what is keeping you warm and de-misting your screen Nov to April
If it is providing a useful service was it wasted?
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Post by vtsnowedin »

Pepperman wrote:Also most EVs can be pre-conditioned, i.e. brought up to temperature just before you need them and while still plugged in. It won't take that much energy to maintain that temperature over a typical commute. But on longer journeys heaters do take a toll on EV range.

I'm sure I saw some data on temperature effects from one of the UK EV trials but I can't remember which one it was....

ETA: Ah here's one from 2014:

http://www.cenex.co.uk/wp-content/uploa ... report.pdf

I guess a kW or two of heat is relatively small beer up against tens of kW of motor power needed to drive the car.

I have to reserve judgement until I have seen one driven in a blinding winter storm in Vermont with minus 35C temperatures. What works OK in Kent might be a dismal failure in the hills of Vermont or the Scottish Highlands.
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Post by PS_RalphW »

Minus 30 and I think EVs will struggle. However they do fine in Norway year round. My leaf has 100 miles max range from a nominal 24kwh battery, at say 40 mph average speed that is 10kw average consumption, so 2kw heat would cut range 20%. In cold weather better to drive faster and spend less total energy heating the car.
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Post by woodburner »

Bear in mind lithium batteries have peak "efficiency" around +30ºC.
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Post by Pepperman »

vtsnowedin wrote:I have to reserve judgement until I have seen one driven in a blinding winter storm in Vermont with minus 35C temperatures. What works OK in Kent might be a dismal failure in the hills of Vermont or the Scottish Highlands.
Fair enough. I've never thought that pure EVs are appropriate in all places (although I suspect they are appropriate in 99% of places).

Stick an ethanol or LPG range extender in there for the more extreme environments and you'll have plenty of heat / coolth / range available.
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Post by johnhemming2 »

clv101 wrote:This article runs the numbers on EV emissions and power generation.
I haven't had the time to look at this in detail, but I have run a rough estimation of the electricity needs (running at 50% of the raw fossil fuel) if all the transport energy use currently swaps to electricity and this would be an order of magnitude higher (ie around the current generation requirements).

Hence I am not that confident in this prediction.
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Post by Pepperman »

A doubling sounds high to me.

The analysis Chris linked to assumes 70% of new cars are electric by 2040. I don't know what that translates to in terms of the total stock of electric cars at that point but I wouldn't be surprised if it was in the region of 50%.

Looking at it another way, we have 32m (erk..!) cars on the road at the moment driving about 8000 miles each. Assume 0.3kWh/mile (taking into account charging efficiency) and you've got about 75TWh. For comparison, UK electricity demand is just over 300TWh so electrifying all cars is about 25% of final demand.

Passenger cars account for half of total transport energy demand (rail, road, water, air) at the moment so I reckon I would put it at closer to *about half* of current UK final demand. But electrifying all road freight will be challenging (not to mention electrifying domestic aviation or water transport). Even electrifying *all* rail is unlikely given that it would be horrendously expensive relative to the number of passengers moved on many of the more rural parts of the network.
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Post by emordnilap »

Pepperman wrote:Fair enough. I've never thought that pure EVs are appropriate in all places (although I suspect they are appropriate in 99% of places).
The latest Tesla promises 300km on a charge, which makes it a good car for most people in Ireland. In fact, it'd do for most people in these isles - that'd be a fair whack of driving without a break.
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Post by adam2 »

If significant numbers of EVs are to be used UNDER PRESENT CONDITIONS then these will in effect be natural gas powered vehicles. Mains electricity comes from a variety of sources, but the marginal source is natural gas, and to a much smaller extent coal.
That is any EXTRA demand is met by burning more gas, at least in the near term.
Wind, solar and hydroelectric sources are expensive to build but have negligible running costs, and are therefore almost always fully utilised.
Nuclear is even more expensive to build but cheap to run and therefore runs continually at full load if available.

Therefore if future EVs are to be renewably powered, we need a lot more wind and solar generating capacity, or in theory hydro.

Widespread adoption of EVs could increase the percentage of renewable energy used for electricity production. PV and wind are inherently variable, and this limits the amount that can be accepted by a conventional grid system.
If however a few GW of smart chargers were used, a lot more renewable energy could be utilised. A skilled human, or a sophisticated computer program would continually monitor production and demand. If for example power from wind dropped by 1GW, then EV charging demand could be dropped by 1GW. The weather forecast and previous experience would then advise as to whether waiting a bit would give more wind/less demand or if CCGT plant should be started.
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Post by Pepperman »

emordnilap wrote:
Pepperman wrote:Fair enough. I've never thought that pure EVs are appropriate in all places (although I suspect they are appropriate in 99% of places).
The latest Tesla promises 300km on a charge, which makes it a good car for most people in Ireland. In fact, it'd do for most people in these isles - that'd be a fair whack of driving without a break.


Completely but there's always someone who wants more than that so they'll be catered for in some way. Tesla does achieve great range but it does that using a massive battery which puts it out of reach of most.

I'm waiting on light weight, small battery and therefore low cost EVs to hit the market. Essentially I wish the people behind the Loremo would get it going again as an EV...

https://en.m.wikipedia.org/wiki/Loremo

But some other young Germans are going down the right path:

https://www.sonomotors.com

Whether they can get to production or not remains to be seen...
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