[Closed] Are electric cars really greener

The big problem with hydrogen is not simply that the infrastructure isn't there. It's that hydrogen is a tiny tiny atom. It diffuses though steel storage tanks. And you have to liquefy it and keep it cool to have a workable rang. And then some of that boils off which you have to deal with. And so on.

MaverickBoy... care to expand on your claim that electric motors are less efficient under load than an IC engine?

I wasn't aware that IC engines were capable of operating at efficiencies over 90%, which is where an electric motor would operate.

Fair comment

I meant "cradle to grave" in terms of sourcing/creating the power supply in the first place. Most of the time that electricity has been created by burning a fossil fuel in the first place. An electric motor may be 90% efficient at turning the electricity it uses into forward motion, but how efficient were the methods created to make that electricity? If you're going to burn a fossil fuel to make a car move, why not just burn it in the car, rather than burn it at a power station to create the electricity to make it move?

OK, sorry, I'm being a bit simplistic. As time moves on perhaps we might be able to make the vast majority of our Electricity in greener/cheaper/more efficient ways (though not in my lifetime I'd warrant), but currently all using electricity to power a car is doing is adding a step into the process of turning a fossil fuel into forward motion in a car! And as anybody who knows anything about Lean Manufacturing will tell you, adding anything unnecessary is not good!

Nice try... but you actually said this...

An Electric Motor is not as efficient as an I/C engine under constant load, in terms of energy required per KW of power produced.

Where Electric Motors are more efficient than I/C engine is under acceleration and deceleration. I/C engines require a lot of extra energy to accelerate in comparison, but Electric motors also have the added bonus of being able to be used as a generator, thus giving energy back to the battery, under deceleration.

If what you say now is true, then no matter whether the electric motor was accelerating or deccelerating, the IC engine would be more efficient...

:oD

As I recall ( and it's been a while)

A decent coal plant is up to 41% efficient more with some of the entertaining things you can do with ionised exhaust gases, and steam.

CCGT up to 50% efficient.

So electric motor at 90%, 40% at the power station and say 10% losses for grid and distribution - about 33% efficient. Allow a bit for the charger and you still beat the 25% that the car does.

And that's before your energy comes from a big old windmill (the power station had the most effect if you noted).

The car battery through an inverter can help with variability on the grid so a good system all round.

Note that I say system, because it is how our energy system works all round that matters. Electric cars can be part of it, as can some hybrids, hydrogen less so. By the way the idea of getting a corgi fitter for a hydrogen system scares me silly.

Check out some of Goran Strabac's stuff - he is one of the countries experts on energy systems and someone it has been my pleasure to share a platform with at IET events.

right:

1. drive less, e.g. homework 2/5 days a week
2. crack seawater adjacent to the nuclear/renewable plant, very efficient, no transmission loss.
3. put hydrogen in standardised canisters
4. drive canisters to supermarkets in trucks also powered by canisters
5. consumer buys canisters with grocery shopping
6. consumers run high performance, zero-exhaust hydrogen cars
7. scrap entire petrol infrastructure: rigs, pipes, storage, depos, tankers, stations, the lot.

Bingo [except for how to make the canisters into re-usable, safe effective fuel cells - whoops!]

SOrted!
Just remind the consumers that
In a parked car, an entire tank of liquid hydrogen fuel will completely evaporate in just 3 weeks. 😮

Battery tech has got to come a hell of a long way before it makes electric cars viable. I'm not sure how true it actually is, but theres that oft quoted thing about the Toyota Prius being more environmentally damaging than a V8 Range Rover (in terms of from 'cradle to grave'). As I understand it, the major reason is the battery, mercury mined in canada, treated in africa, assembled into batteries in China, before going into the car in Japan. Its no wonder a replacement battery is so horrifically expensive. A friend of mine used to work in a Toyota dealership and one customer had a grey import Prius, and the pack gave up, I believe the quote for a replacement was around the £14,000 mark! Its also why I'm led to believe that buying a new Prius is subsidized by the Government, as the real price of one means its just not realistic.
I know this is going slightly off a tangent, but I'm trying to say/show that electric cars for now, just aren't realistic and are one of those aforementioned 'big white elephants'.
Unless of course there's a massive leap in battery technology.

I wasn't aware that IC engines were capable of operating at efficiencies over 90%, which is where an electric motor would operate

I do believe batteries are lossy too. You don't get out as much energy as you put in.

The biggest problem imo with hydrogen is energy density. A tanker full of H2 is going to drive some cars some miles.. but a tankerload of crude oil is going to drive more cars further, and also make plastics, paints, fabrics, chemicals etc etc etc etc. So it's way more cost effective.

As for electric cars, well I reckon they're great for city cars. After you drive one for a while and then you go back to a normal car it seems horribly wasteful to sit there in a traffic jam burning fuel for absolutely no reason.

As for hybrids being greenwash, I am not sure I agree with that. A Prius contains less metal than a normal car and the battery's only a carry-on bag sized bit of nickel. The so-called studies that alleged Priuses were less green than Hummers was total rubbish. New Prius is rated at 89g/km CO2, that's quite hard to beat with any car, never mind a decent sized family car.

ooOOoo - Member

SOrted!
Just remind the consumers that
In a parked car, an entire tank of liquid hydrogen fuel will completely evaporate in just 3 weeks.

Pardon my french, but WTF are you on about?

A friend of mine used to work in a Toyota dealership and one customer had a grey import Prius, and the pack gave up, I believe the quote for a replacement was around the £14,000 mark!

Pete, you are wildly misinformed. Think about it mate - if the battery cost £14,000, how could the entire car only cost £17,000? Why on earth would the government throw tons of money at it without even telling anyone about it? The batteries by the way are about £1800 I believe for a whole one, but they are modular so you can replace the cells that are faulty. They are NiMH batteries, which are nowadays mecury free, and they are carefully managed (ie always kept between 40-80% charge unlike the ones in your bike lights) so that they last for many years. They are built to California emissions equippment standard which requires them to be guaranteed for 10 years, so clearly Toyota have confidence. There's a taxi in Canada that last time I read about it had done 300k miles and only needed the same things that normal cars need.

Toyota are a well respected car manufacturer. Why would they put years of R&D into making something that made no sense and try and flog it? Remeber Bush scrapped the US Govt electric car programme when he came in...

In a parked car, an entire tank of liquid hydrogen fuel will completely evaporate in just 3 weeks

Hmm, I wonder how the people that supply hydrogen to labs and stuff get around that? 🙂

[i]Eeerm, there's a blue ford focus running round sheffield at the moment with this fitted. It's a standard two litre petrol engine with a very simple conversion kit that is fitted into the fuel system on top of the engine and there's an additional pipe run to the boot where the tank is. The engine hasn't been removed and everything else is standard, i pretty sure the engine management system wasn't touched either[/i]

I think you have the wrong end of the stick. We're not going to BURN hydrogen !.

The Honda uses hydrogen to produce electricity to run its electric motor, employing an onbaord fuel cell to do this. 🙄

An incredible achievement in itself, to have an onboard fuel cell.

I'm gonna try sticking to posting what I know. As I've pointed out, I've worked in the industry and been in the same room as some very clever men who have half the alphabet after their name, men who have sat down and looked at all serious altenatives, at the request of the car company "big-shots". For the reasons I have pointed out, hydrogen isn't a starter, imo.

Solo.

Cellulosic Ethanol is the way forward. Or at least one of them. Solar powered H2 in sunny areas...

molgrips - Member
but a tankerload of crude oil is going to drive more cars further, and also make plastics, paints, fabrics, chemicals etc etc etc etc. So it's way more cost effective.

As for electric cars, well I reckon they're great for city cars. After you drive one for a while and then you go back to a normal car it seems horribly wasteful to sit there in a traffic jam burning fuel for absolutely no reason.

As for hybrids being greenwash, I am not sure I agree with that. A Prius contains less metal than a normal car and the battery's only a carry-on bag sized bit of nickel. The so-called studies that alleged Priuses were less green than Hummers was total rubbish. New Prius is rated at 89g/km CO2, that's quite hard to beat with any car, never mind a decent sized family car.

Yep, it was a dust to dust study, and I think it was the Jeep Wrangler that came out as the vehicle with the lowest carbon footprint. Being a US study that was the V8 petrol version, naturally.

I don't know what the solution is going to be - possibly not the "best" one... but it will be whatever most manufacturers get behind, and almost certainly with government support (possibly whatever fuel source the US government decide they are going to use for their military vehicles... or China... or someone else influential on the global stage).

It's a shame money wasn't thrown at things like this, renewable energy production and solving climate change rather than to fund a few bankers lifestyles for the forseeable future. Hey ho... it's all about money at the end of the day.

Oh and its pretty much the whole base of the rear seat, the battery is massive!

It's not mate, I'll take some pics of mine if you like. It goes between the shock pillars in the boot and takes up about half the floor - at least, the space for it does; the battery has air surrounding it. From what I can gather from the net it weighs 38kg ish and its volume is about 22l, which is round about the size of a carry on bag 🙂 [url= http://www.toyotapriusbattery.com/ ]- from this site[/url]

I would bet that the engine, motors and battery in a Prius weigh less than the larger engine and gearbox in a normal car.

Quick google moment, Toyota is 'encouraged' to produce environmentally friendly vehicles, the price you pay is subsidized by Toyota, it all goes round in green/carbon credits and that rubbish. So each Prius Toyota sells is at a loss. I've just been reading another [url= http://www.cato.org/pub_display.php?pub_id=4288 ]site[/url] suggesting that Toyota is/was loosing $17,000 on each one!
More google gen, I said that Prius I mentioned was a grey import. http://www.toyotapriusbattery.com/ I'll let you read that.

Yep, it was a dust to dust study, and I think it was the Jeep Wrangler that came out as the vehicle with the lowest carbon footprint. Being a US study that was the V8 petrol version, naturally.

The study I read was garbage. It claimed that the total energy cost of a Prius was about half a million dollars. That would be an amazing feat for Toyota in a $20k car. I am not a paranoid conspiracy theorist but I know that those evil bastards known as "lobbyists" in the States pay for crap science like this on a regular basis.

The reason the prius is a greenwash is you can get much much better total lifetime emmisions using conventional technology. Its MPG is not remarkable in any way and that battery is polluting to make.

A small light simple car designed to have long life and high mpg is a much better bet. Of course a small light simple hybrid would be good - but that is not what a prius is. Its a big heavy luxury car. All that weigh involved environmental penalties. It takes energy to accelerate it and it consumes raw materials.

I would bet that the engine, motors and battery in a Prius weigh less than the larger engine and gearbox in a normal car.

Pete mate did you really read that link you posted, on Cato?

a) Did you see the tag line on the site was "Individual Liberty, Free Markets and Peace"? That means that it's a right wing talking shop and will be biased as hell against anything eco.

b) That article was published in 2001 which, particularly in the US was a million years ago in terms of eco-awareness. It also refers to the MkI Prius which was pretty crap.

c) It talks about a potential government subsidy to BUY a new car, not manufacture one. The subsidy went ahead, and you got like $2,000 off the list price of the car in the US for a limited number of cars I believe. The list price was still something like $25-$35k in the US even without the subsidy.

d) It says not many Priuses had been sold which was surely true of the MkI but the newer model (the one you see here) sold like hot cakes. The milion car mark was passed what, two or three years ago?

There are two electric motor/generators in a Prius, both of which are pretty small, you'd hold them in your hand. There are a few more cogs and that's it - no gearbox. The engine is also a small 1.5l one based on the Yaris. So weighed against a typical 1.8l petrol engine and gearbox I bet it comes out on top. Against a competing diesel engine there'd be no contest.

I do seem to know a lot more about Priuses than you do mate, choose your arguments more carefully 😉

Molgripos - one 1.5 l petrol engine and drivetrain will weigh much what another does. The prius has an additional weight of the elecrtic motors, batteries and all the associated wiring and gubbins - I bet its 50 kg more.

Mate, there's no gearbox in a Prius. Gearboxes are very heavy.

I'm not sure how it being 'right wing' will make it automatically biased against anything eco, but the Prius is not eco friendly. For obvious reasons.
So a Prius in the US was 25-35k? So approx 50% LOSS on EACH car? Way to go, as they say in the States.
Oh and there was a huge surge in sales of European/small/economical cars in the States when the price of crude oil went through the roof, it dropped back and they went back to buying V8 trucks. Swings and Roundabouts.
Comment above about a smaller lighter car with modern technology will blow the Prius MPG figures is spot on. I can't wait to see how far solenoid controlled valves will take a diesel engine. Fiat's Multi-Air petrol engine is a good step to prove if its reliable in the real world. If one of my colleagues can extract 80+mpg from a old (L reg) VW Passat 1.9Tdi with some careful driving, what could you do with modern tech?

I think you have the wrong end of the stick. We're not going to BURN hydrogen !.

Nope, right end of stick, obviously not got enough letters after my name though to explain myself clearly so wont try again.

Anyway the answer is clearly the [url=I think you have the wrong end of the stick. We're not going to BURN hydrogen !.]fuel cell push bike[/url]

Surely it does have a gearbox - just not a conventional one. There must be some sort of gearing to get the power from the petrol engine to the wheels

Here is a pic from wiki - looks no smaller and ligher than a conventional gearbox and starter motor.

molgrips - Member
Mate, there's no gearbox in a Prius. Gearboxes are very heavy.

[url= http://www.businessweek.com/autos/autobeat/archives/2009/04/the_prius_insig.html ]This[/url]

So approx 50% LOSS on EACH car?

Er no. I'm saying the info in that article is WRONG. Toyota made a loss at first because they spent a decade on R&D and sales of the MkI were slow. However, SINCE THAT ARTICLE WAS WRITTEN they have sold well over a million cars. So they are profitable now. [url= http://www.businessweek.com/autos/autobeat/archives/2009/04/the_prius_insig.html ]This[/url] article suggests that Honda make 15% profit on new insights, and Toyota somewhat less on Priuses. That's still in the black tho.

It would be possible to get more MPG from a very small car but the point is that the Prius is a big car that's as economical as a very small one. FWIW averaged over a whole tank of fuel I get 57-62mpg in the summer and 52-54mpg n the winter, driving at the speed limit all the time and including plenty of town driving. The car came out in 2003 and those figures are only just being equalled now for comparable sized cars. Of course the new Prius is even better. Last time I checked I couldn't find any car with better emissions than a new Prius, never mind anything of a similar size.

Your mate did not get 80mpg from an old Passat driving sensibly over a long period. That must've been one particularly good trip.

If what you say now is true, then no matter whether the electric motor was accelerating or deccelerating, the IC engine would be more efficient...

But under deceleration an I/C engine is still burning fuel (even if only a small amount) to keep the engine running... An Electric Motor is not only NOT using any electricity under deceleration, but is actually charging up the battery instead! Ergo different power sources are more effective/more efficient under different circumstances.

Why bother building a hybrid car in the first place otherwise?

If you want to know how the thing works, check this out:

http://eahart.com/prius/psd/

It's bloody genius. I think it was invented by some Japanese bloke and then bought by Toyota up front.

But under deceleration an I/C engine is still burning fuel (even if only a small amount) to keep the engine running...

That's not true with fuel injected cars, and it's never been true of diesels.

TJ - nice pic find, that gearbox has got to weigh a ton! 😛 😉
Interesting to see it in cutaway, so we've got a clutch pack, generator run on the first input shaft and differential type connection on the other end of the input shaft allowing the electric motor to run at different revs to the engine. Would be nice to see where the chain drive goes to and how it transmits power to the road wheels.

Surely it does have a gearbox - just not a conventional one. There must be some sort of gearing to get the power from the petrol engine to the wheels

CVT Gearbox in a Prius isn't it? Not been in one, but my old boss used to have one of those Lexus 4x4 Hybrids (bit of a marketing exercise there if ever there was one!) which the petrol engine powered the wheels through a CVT box I'm sure. Or at least that's what it felt like the couple of times I drove it.

It would be possible to get more MPG from a very small car but the point is that the Prius is a big car that's as economical as a very small one. FWIW averaged over a whole tank of fuel I get 57-62mpg in the summer and 52-54mpg n the winter

My old company car, a 2007 BMW 320D, was arguably a bigger, heavier, more luxurious car than a Prius no? It used to better those MPG figures easily! OK, not if I had my foot the the floor, but driving at the speed limit everywhere would see it into the 60's MPG wise.

Your mate did not get 80mpg from an old Passat driving sensibly over a long period

Agreed. Some creative maths here methinks. I've now got an N plate Golf (no company car when you're on the dole! 😉 ) with the same 1.9TDi engine. It's a great engine for what it is, remarkable in fact when you consider at the time it came out all other diesels were crap underpowered junk with nowhere near the economy. But in my Golf, a lighter car than the Passat, the absolute best I've achieved when driving very sensibly is about 56mpg out of a tankful. More normally I achieve between 48 and 52mpg depending on whether or not that's more town or open road driving.

No clutch in a Prius. Check the link I posted.

The HSD does indeed feel exactly like a CVT but it is NOT a mechanical CVT variable pulley system like in normal CVT gearboxes. All the gears are permanently connected to each other in fixed ratios. Road and engine speed are managed by varying the power to or from both motor/generators.

If you can get 60mpg from a tankful of diesel in a BMW with 50% time spent driving in traffic I'll eat my Prius owners manual. Government rating is 58mpg combined tho, so maybe if you were lucky. 128g/km CO2 though which is more than my 104g/km and a whopping 40% more than the 89g/km of the current Prius. Remember that petrol is much cleaner than diesel gallon for gallon, and when we had our worst fuel prices it was a lot more expensive too. I'd say that a BMW 3 series is not bigger than a Prius.. they are quite spacious inside.

the point is that the Prius is a big car

That's not true with fuel injected cars, and it's never been true of diesels.

LOL

You SURE of that?

On some of the VERY latest diesels, yeah you're right. But on just about anything else, regardless of whether or not it's fuel injected, the engine is still burning a very small amount of fuel (approx the same amount as if it were sat idling).

Molgrips, your right he didn't get 80 mpg from an old passat on average, he only manages about 77-8mpg then. :p
He can get the 80+ on a trip from Nailsworth to Gloucestershire airport, but can't do as well on the way back.
That Prius planetary gear setup is nothing new, and I'm not being funny. That setup, albeit with 3 planetary gears (instead of 4 and a multiplate clutch pack) is what connects the rear wheels of my Cavalier 4x4 with the front axle.

You SURE of that?

On some of the VERY latest diesels, yeah you're right. But on just about anything else, regardless of whether or not it's fuel injected, the engine is still burning a very small amount of fuel (approx the same amount as if it were sat idling).

Oh, almost forgot 😆 😆

I get 53mpg on tank from my 1.7 non-turbo diesel 1998 Vauxhall Combo, just shows that the prius is nothing remarkable. Though my van won't do more than 88mph downhill lol.

Agreed. Some creative maths here methinks. I've now got an N plate Golf (no company car when you're on the dole! ) with the same 1.9TDi engine. It's a great engine for what it is, remarkable in fact when you consider at the time it came out all other diesels were crap underpowered junk with nowhere near the economy. But in my Golf, a lighter car than the Passat, the absolute best I've achieved when driving very sensibly is about 56mpg out of a tankful. More normally I achieve between 48 and 52mpg depending on whether or not that's more town or open road driving.

Well I'm sure - on overrun the fuel injection will shut off.

LOL

[Tommy Cooper Impression Voice]"Just Like That!"[/Tommy Cooper Impression Voice]

Just shuts off does it? What tells it to start again? 😉

It's the way a car is mapped... Some very modern cars are mapped so that the engine is indeed burning no fuel under deceleration (which is still less efficient than an electric motor actually recharging a battery, but nuff said there!). Only some very modern cars though.

I'd absolutely LOVE to hear how a diesel engine with Mechanical fuel injection doesn't provide fuel to the engine under deceleration still. Otherwise it would never tick over! 😕

You have to realize, that the driver in questions has spent years perfecting a technique of engine off coasting, shutting the engine off at lights and absolutely no change in throttle travel.

OK fair enough, and I suppose the route that you described takes in a big section of downhill the one way too, hence why he can't manage the same MPG on the return route.

In terms of interior space it's certainly not a big car

It's bigger than a Golf - as big as an older Passat. You talk like I've never been in one.

You SURE of that?

Yes. The forward motion of the car is what keeps the engine turning. Why inject fuel?

That Prius planetary gear setup is nothing new, and I'm not being funny

Planetary gears have been around for years. The use of that setup with two motor/generators for driving a car is new. The MkI Prius was the first car to have it - 1997.

As for the 80mpg story - he must've been driving like a snail. Anyone else who's driven one of those cars (and there are a lot of us about) can tell you that's not practical for normal driving ie not stupidly slowly.

In my other car, a Passat 2.0 TDI, I have got 54mpg on a long 70mph run on summer diesel, but the long term average since September is about 42 or so. What's interesting though is that that can drop to the low 30s when you get stuck in traffic. The Prius handles traffic way way better, which is where we came in isn't it? Suitability of different drivetrains for different conditions?

Yes. The forward motion of the car is what keeps the engine turning. Why inject fuel?

Totally, why inject fuel indeed...

Only something that has been addressed MUCH more recently than you might think though!

I'd absolutely LOVE to hear how a diesel engine with Mechanical fuel injection doesn't provide fuel to the engine under deceleration still. Otherwise it would never tick over!

You really want me to dig out the schematics for the Bosch VE pump? From memory there's a governer that shifts the control collar to provide more fuel to the plunger when rotation speed drops below a certain amount. That's how it idles when you have your foot off the pedal, and also why it uses no fuel when the forward motion of the car is spinning the engine and hence governer and your foot's off the pedal.