[LINK] Standards, please! The third coming of electric vehicles
francisoconnor3 at bigpond.com
Sun Apr 22 02:02:22 EST 2012
On 21/04/2012, at 7:53 PM, Karl Auer wrote:
> On Sat, 2012-04-21 at 01:51 +1000, Frank O'Connor wrote:
>> - They don't do away with the problem of pollution
>> and green house gases.
> The primary driver behind most alternative liquid fuels is that oil is
> running out.
But the supply of hydrocarbons seems to be increasing if natural gas, fracking, shale oil, shale gas, and other sources are taken into account. The current estimate is that we have 500 years or more of hydrocarbon fuel sources at current or better than current demand levels. Yeah, the 'easy peasy' hydrocarbon source (oil) is running out, or has hit peak ... but others are coming into play as it goes the way of all things.
>> - Cost of production is as high, if not higher, than the current oil
>> based alternatives ... and unlikely to shrink dramatically over the
>> coming few decades.
> Which will be irrelevant when the oil runs out :-)
See above. The other sources I mentioned are probably just as economically viable as biofuels, but with fewer down sides regarding land use and the like. (Of course fracking may seriously mess with any land it is carried out under, and the water tables and underground cisterns it destroys ... but that remains to be seen.)
Another more ecologically and carbon sustainable fuel ... hydrogen ... could be created using salt water and solar/wave/whatever sustainably generated energy, in serious abundance. The initial capital and infrastructure costs would be high, but once set in play it would provide an alternative that ticks most of the boxes.
>> b) Electric also comes with its problems:
>> - Generation of same still causes pollution ...
> Not if it is generated from any of a dozen alternative sources such as
> wind, sun, tide - and many of these are available right now.
Mmmm ... I have a roof full of solar cells that generates about 1600-2000W per hour at peak ... which covers most contingencies (except heating, cooling, cooking and other high demand periods when I have multiple devices going.) And I'm just a single bloke. That said, it does reduce my power bills nicely.
>> - It's marginally more efficient that internal combustion per power
>> unit generated, but loses a heap of that advantage in the transmission
>> of same.
> Only if you transmit it. Local clean generation is possible *right now*.
Not to the level of a family's complete needs. Sad fact of life but we live in a pretty energy intensive age. Unless we can make the devices an order of magnitude more energy efficient (like they have done with light bulbs) the power requirements will always tend to be more than we can locally generate. This applies especially for applications and devices that have a primary purpose of producing or reducing heat ... whose whole design currently requires that they be energy inefficient (it’s the inefficiencies that produce or reduce the heat).
>> - Battery technology still sucks. Eight to ten hours for a complete
>> refill on an e-car (four to five for an 80-90% refill), only storage
>> of enough to travel a 100 - 150 Kms or so with any confidence, bulky
>> and heavy enough to appreciably reduce the performance of the cars
>> into which they are installed.
> All vehicles must propel not only payload but also their propulsion
> system, chassis and ancillary systems. In what way do you mean that
> performance is reduced/ Or do you just mean that the weight of the
> propulsion system is a greater proportion of the total weight of an EV
> than it is with FFV?
Think of your average Atlas (or Energia or other 3 stage) rocket ... 80% of its weight was the fuel it needed to get off the ground, a further 15% was the primary and secondary engines housed in their protective casings, 2-3% or so was all the stuff that was going into orbit (the capsule, astronauts, life support systems etc etc.) The other 2% was the engine and fuel necessary for the de-orbit manoeuvre ... which thankfully had a hell of a lot of inertia to assist it.
Now compare the current fully electric car, with the current fully hydrocarbon powered car. Comparatively speaking the Tesla and the Lotus Exige have the same body, size, carry capacity and comparable performance, but the Tesla weighs three times more, and it consequently expends more than twice the energy to reach the performance envelope of the Exige without having anything near its range and endurance.
The reason for that is that the fuel source (battery vs fuel tank) is much heavier on the Tesla than the Exige. Sure, the motor weighs much less ... but the Tesla is basically just a mobile battery set, whilst the Exige just happens to have a relatively small fuel tank embedded in it.
>> OK for short trips, not ideal for long ones ... and in Australia, the
>> US and other big countries that is fatal for a general purpose motor
> Sigh. No, it's not. It is *perceived* as fatal. For the *vast majority*
> of trips undertaken by Australians, the range is ample. And it will in
> any case increase with time. No-one is suggesting that EVs are suitable
> for long trips, any more than they would suggest that a family sedan is
> appropriate for, say, hauling wheat.
For urban travel ... no problems (with some qualifications).
But I live 125 Kms from Melbourne and about 200 Kms from any other population centre over 50000 people ... so it's not really terrific for me.
And our way of life predicates holidays down at the beach, weekend or day trips with the family, and little numbers like fishing, surfing, hunting, swimming and the like which take us outside the urban environs with monotonous regularity ... and e-vehicles don't cut the mustard for that.
>> - Electric engines (and the transmissions that serve same) aren't
>> exactly the most efficient in design or operation at present. Gimmicks
>> like turning the motor off when stationery, coasting and dual powered
>> machines like the Prius and others that charge off the petrol motor
>> are just that ... until electric can stand on its own. They are an
>> interim approach with little to recommend them long term.
> Electric engines don't *have* transmissions, except for forward and
> reverse. There is no need for gears, because an electric motor develops
> the same torque at any speed. As to which "gimmicks" will end up being
> useful long-term - it's hard to say. Regenerative braking doesn't make
> much sense to me, for example, but having a small auto-started
> liquid-fuelled motor running at optimum revs to charge the batteries is
> an idea that seems to have both advantages and disadvantages. Time will
Currently all vehicle engine have transmissions ... electric ones just miss out on the gears.
They are typically designed to use a direct drive shaft to the differential which transfers the energy to the axle, which rotate sand turns the wheels. Pretty sensational design, huh?
Well, yeah ... if you're limited to one engine (given the limitations of internal combustion engines where you are limited by size, weight, fuelling and exhaust factors). But why should designers follow this same inefficient route when using electric engines?
"OK Bruce, here's what we do ... we mimic the internal combustion design and go for all the power inefficiencies inherent in a single heavily encased shaft drive system. I mean, it's worked for 120 years ... why mess with it?"
So, here's a few thoughts prompted by your comment above ...
- Why not install multiple smaller engines in an electric car?
- Why not install them in the wheels?
- Why not make the drive system inherently 40-50% more efficient by doing so?
- And wow! That gives us a 40-50% increase in range!
- And now we have SERIOUS four wheel drive, rather than just two axles mediated by a diff, at work. Imagine what that could do for car handling and rubber to the road efficiencies!
There are HEAPS of other design implications that pertain to electric vehicles and making them more efficient that are NOT EVEN BEING LOOKED AT by any manufacturer at the moment ... because they are so locked into the mind-set of the original internal combustion vehicle design of the late 19th century ... which is an incredibly inefficient design for electrically powered vehicles.
>> - Battery charging/replacement infrastructure is lacking ... as is a
>> battery design that can easily and quickly be replaced at something
>> like your local service station. Refuelling convenience is currently a
> Recharging will happen at home or at common destinations like
> workplaces, hotels, airports, train stations and so on. There really is
> no point considering EVs for long-distance travel at the moment.
Well, I have an e-bike with a 200W motor on the front wheel (that's basically there to assist rather than be a primary drive unit - which would require about a 750W unit not legal in Oz at the moment) and it takes me 8-10 hours to fully recharge it, and 4-5 hours to get to about 85% charged ... and that's just for the 5Kg battery that's servicing the motor (the battery which, by the way, retails at $500 odd bucks).
Given that, I shudder to think what a moderate size (say a 10,000 WH) e-car would take in the way of power drain from the house, and how long it would take (especially given the less efficient multi-battery design). Even top-ups take a few hours on my bike ... and whilst it is topping up I can't use it.
> However, if the market is there for charging points I guess it could
It's a product confidence thing. Unless Joe/Josephine Public can be assured that they can refuel and repair the family car at regular, local and convenient locations then they would be rightly hesitant about getting onboard the e-vehicle train (no pun intended).
And the way the batteries and their siting in e-vehicles are designed at the moment, embedded in banks throughout relatively inaccessible locations on the car, makes even the idea of a quick swap-out/swap-in refueling station impractical.
And lets not even get into the problem of lack of standards for batteries, connectors and battery types.
>> - Generation of electric is restricted at the moment to major power
> No it's not! Anyone with a bit of roof space facing vaguely north can
> get into power generation. And locally generated power gets rid of the
> whole transmission losses thing. The single most energy efficient thing
> we can possibly do is generate power near where it will be used.
Like my roof you mean? The roof that generate between 1600-2000W per hour at peak? The roof that's gonna refuel the e-vehicle that needs to put out about 10,000 KWh to operate? That roof? :)
Unless there is a HUGE improvement in solar cell technology over the next few years, that means I will have to rely on the mains to refuel the car (or add to my solar cells by a factor of about 9, and site them around what used-to-be the garden, on the fences and probably also on the nature strip out front - hope the Council won't mind).
> Luckily you went on to say...
>> - Electric can be supplemented by the consumer with improved solar and
>> other technologies to power their vehicles ... and even a 10-15%
>> supplement would appreciably reduce demand on the centralised sources.
>> - It's so much quieter, cleaner and less intrusive than the roar of an
>> internal combustion engine (especially on weekend mornings and the
>> like when I want to sleep in). For that alone I would vote the Nobel
>> Prize to anyone producing a viable electric car ...
> There are already viable electric cars. There have been viable electric
> cars since the seventies, it just depends on what you mean by "viable".
> If you demand the exact same set of characteristics as you expect from a
> FFV, then obviously you find no candidates to meet your exactin
> criteria. If you want a car that will satisfy most requirements of most
> urban dwellers and quite a few regional dwellers, then there are already
> perfectly useful EVs.
You and I have different ideas of what is 'viable', Karl. :)
> And yes, cost is a bummer at the moment.
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