OT: Electric cars; how green are they?

[jgharston]

I remember a scifi story where that technology was used in the big cities and motorways. You knew you were getting into dodgy areas when you had to switch your car to internal power.

I've spent 20 minutes trying to google for it, but can't remember enough details to make a sensible search. It was set in a future UK where the country had been split down the middle north-south, with the east being the well-off industrial bit and the east being rural agricultural. I remember it as Sheffield was on the wild frontiers were the border was porous enough to defect/sneak in For an English class I wrote a bit about the Isle of Wight being a joint administration neutral zone sort-of place.

JGH

[Roger Chapman]

Not the same story but Robert Heinlein wrote a short story about the perils of broadcast power - Waldo. Lead overcoat anyone? (I think that was in it).

[tony sayer]

In article , Dave Plowman (News) scribeth thus

Well over those sort of distances yes, they would be. This would be a lot closer and is yet to be developed...

[The Natural Philosopher]

There are two real buggers of a problem in mankinds search to deploy energy effectively.

One is energy storage, without fossil fuel and the other is supplying energy to vehicles, without fossil fuel.

This is a third philsopohical one, and that is how to teach politicians enough basic science (or humility) so they either stop meddling in energy policy or listen to those who actually know how stuff works.

[Colin Stamp]

Maybe. Can you show me any better figures for real-world cars? I suspect the true achievable value is somewhere between the Tesla and your estimate. That's before you start charging them at humongous rates of course.

Cheers,

Colin.

[Alan Braggins]

UK limit is 200W for standard bikes, 250W for tandems and tricycles:

200W is the equivalent of a fairly fit cyclist pedalling to help you, with less weight penalty than using a tandem: for something that can be legally be treated as just a standard bike, I don't think it's too daft. If you want to go faster, use something that is legally an electric moped and regulated accordingly. (Or become a better cyclist - a serious racing cyclist will go faster than a legal electric bike, and further.)

On the other hand a basic 200W hub motor built for minimum cost won't be as efficient over the full speed range as 200W of cyclist using gears sensibly.

[The Natural Philosopher]

IMHO there are no other real world cars yet. ;-) Right now the driver is not to produce a ressonable alternative to a family saloon. Its to produce a green fashion statement (tesla) or a green fashion statement that gets massive tax rebates(G-whiz et al). Or a heap of crap with green pretensions (prius et al).

There is as yet no real incentive to produce a ford E-focus for example Or an EBMW

[Dave Plowman (News)]

I doubt it could be made close enough to get reasonable efficiency.

[Matty F]

There is a system in use for electric buses with small batteries. Each bus stop has a short section of double overhead wires and each bus connects to the wires automatically at each bus stop. I guess that guarantees that the buses always stop!

[The Natural Philosopher]

Tat is actually interesting. Do y9ouy have more information?

Of course trolley busses used to be common and mostly pretty good.

They would make a perfect solution to some intra-urban transport, especially if they had a bit of battery as well..

[Colin Stamp]

I think some of them do have a bit of battery.

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Chris Hogg saying something like:

To be treated with the usual eco-bollocks caution regarding claims...

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Colin Stamp saying something like:

Glasgow trolleybuses had a 'bit of battery' fifty bleedin' years ago. Not much, and it only took them far enough, very slowly, to maneouvre from one end of the garage to the next, or around an obstruction.

[Matty F]

I can't find the photo that I saw in a magazine at work (where we maintain electric buses and trams, the latter not all electric!) But here's a similar system from China using ultracapacitors:

are quick to charge and cheap and should last indefinitely. They are quite large so unsuitable for cars.

trolley buses have batteries that enable them to run at full power away from the wires for up to five kilometres.

[Mike Barnes]

Chris Hogg :

Not strictly comparable, granted, but I'd like to know what the answer to that question is for the trains that actually run round this country at the moment. You can bet your life that the operators know the exact answer.

[The Natural Philosopher]

Trains are very much better on account of the low drag form factor and potential high occupancy, lack of gradients and very low rolling resistance.

Of course, like the Park and Ride bus I followed yesterday with two passengers on it, low occupancy means a complete waste of fuel.

However the train alone is not the whole story...any more than a wind turbine alone is not the whole story.

[tony sayer]

Ever been to Cambridge station or the line to Kings Cross at most hours of the day?, certainly well occupied;!...

[Andy Champ]

Add regenerative braking on more recent models. A slowing train will pump power back into the grid, where it can be used on another speeding up. And trains have _lots_ of inertia.

Andy

[The Natural Philosopher]

yup.

Ever been to any of the stations on the Newmarket line? ON NOT race day...

[Matty F]

We run up to seven very old electric trams that take advantage of regenerative braking. And in NZ the power comes mainly from hydroelectric dams with a bit of geothermal and wind power as well as a bit of coal burning at peak times. As it happens the trams don't run at peak power usage times. So, no CO2 escaping into the atmosphere. Not that that matters since more CO2 is a good thing as it makes trees and grass grow faster.