Tesla Model S, Third Fire

[tom66]

Two major things need to be fulfilled for Tesla's success:
 - Battery supply needs to be sorted (should be by 2Q 2014)
 - NHTSA needs to clear Tesla on floor mounted pack, as both Model S and Model X engineering are designed around this, a redesign will push them back by years and cost millions. Minor modification might be suggested, but I think overall the main issue was the car just rode too low with such a battery, the firmware update fixed this but pissed off a lot of owners.

Re, some comments on that post are wrong about battery lifespan. Roadster battery is smaller, and less well cooled, yet it has been shown that 100,000 miles with 80 to 85% capacity remaining is possible -- not too bad:
http://www.pluginamerica.org/surveys/batteries/tesla-roadster/PIA-Roadster-Battery-Study.pdf

An equivalent ICE would surely experience wear in engine parts leading to a drop in MPG, though unlike a BEV that could probably be sorted with cleaning and general maintenance.

In 20 years time they'll probably be a market for replacing cells in vehicle battery packs. There is already one for Prius batteries, typically 1 or 2 cells in series string fail.

[nctnico]

The drop in mileage in an ICE is mostly due to emission control systems getting dirty, injectors and spark plugs wearing out. All can be cleaned/repaired with regular maintenance. If you put high quality fuel in your car (with the proper additives for cleaning and dispersion) there is no reason why mileage gets less. 100k miles is a piece of cake for a modern car. I drive my diesel cars twice that distance with no loss in mileage. Besides that if the mileage would get less the engine would send unburned or partly burned fuel down the tailpipe which would cause the annual emission test to fail. Worst case you'd lose some performance.

If I had an EV I wouldn't worry much about wearing the batteries. In most EVs they are pampered.

[woodchips]

Ah ha! Genius, yes it should be kWh, my mistake.

In the Wiki article the first table is for combustion energy density, gas is 46MJ/kg, in the second table it is 54MJ/kg. As far as I can see the value in the first table should be used, combustion. Can't really see why there is a difference between them truth be told. I know that the energy density varies quite a bit depending on whether it is measured condensing or non-condensing, is this the case here?

[tom66]

Combustion isn't 100% efficient... I thought at least 30% was exhaust. Maybe that accounts for it?

[nctnico]

@woodchips:
The discussion is about natural gas not gasoline.

@tom66:
If you burn a kilo of something properly (in ideal conditions) you get an amount of energy in the form of heat. That amount of energy is the energy density.  Efficiency comes into play when you want to convert heat into motion.

[tom66]

Exhaust isn't all heat though? There are gases there with unused energy. (You can tell chemical/petroleum engineering is a weak spot of mine. Not sure what the term is. Not all of the hydrocarbon is used.)

The rule I was told was petrol engines are about: 1/3rd to wheels, 1/3rd as heat and 1/3rd as exhaust (of energy in the fuel.)

[nctnico]

There is some amount of partly burned hydrocarbons and CO coming from an ICE which are 'burnt' in the catalytic converter. But the percentage is quite low. The hot gasses from the tailpipe are mostly CO2 and water.

[tom66]

Top Gear solution: attach greenhouse to rear tailpipe!

[nctnico]

Actually they do that for real:
http://www.omafra.gov.on.ca/english/crops/facts/00-077.htm

Over here most farmers with a green house have their own natural gas powered generator which produces electricity, heat and CO2.

[G7PSK]

Actually they do that for real:
http://www.omafra.gov.on.ca/english/crops/facts/00-077.htm

Over here most farmers with a green house have their own natural gas powered generator which produces electricity, heat and CO2.

They do that here in the UK as well, mostly in Lincolnshire but there is at least one here in Norfolk. Some places CO2 is taken from power stations to grow houses.

[Rufus]

They do that here in the UK as well, mostly in Lincolnshire but there is at least one here in Norfolk. Some places CO2 is taken from power stations to grow houses.

That's a revolution in the construction industry I hadn't heard of

[lemmegraphdat]

Actually they do that for real:
http://www.omafra.gov.on.ca/english/crops/facts/00-077.htm

Over here most farmers with a green house have their own natural gas powered generator which produces electricity, heat and CO2.

They do that here in the UK as well, mostly in Lincolnshire but there is at least one here in Norfolk. Some places CO2 is taken from power stations to grow houses.

And whatever leaks into the atmosphere does the same thing for nature. Think of the Earth as a giant greenhouse...Ha.

[zapta]

Hydrogen/Electric cars are coming to the US next year.

http://www.washingtonpost.com/business/toyota-bumps-up-hydrogen-powered-car-in-us-to-2015/2014/01/06/1c309a06-7716-11e3-a647-a19deaf575b3_story.html

300 miles, slow acceleration, fast refueling time, and as expected subsidized by tax payers' money.

[dr.diesel]

Hydrogen/Electric cars are coming to the US next year.

http://www.washingtonpost.com/business/toyota-bumps-up-hydrogen-powered-car-in-us-to-2015/2014/01/06/1c309a06-7716-11e3-a647-a19deaf575b3_story.html

Not sure they could make that any uglier.  Something they don't mention, how much H does it hold, and what does it cost per unit?

[nctnico]

Hydrogen/Electric cars are coming to the US next year.

http://www.washingtonpost.com/business/toyota-bumps-up-hydrogen-powered-car-in-us-to-2015/2014/01/06/1c309a06-7716-11e3-a647-a19deaf575b3_story.html

300 miles, slow acceleration, fast refueling time, and as expected subsidized by tax payers' money.

The accelleration is more than enough. Most people pull up much much slower even when getting onto a highway.

I'm wondering what the CO2 footprint is. Only 20% of the initial energy used to make H2 makes it to the wheels of an H2 powered vehicle.

[zapta]

I'm wondering what the CO2 footprint is. Only 20% of the initial energy used to make H2 makes it to the wheels of an H2 powered vehicle.

Depending how you generate the electricity. If nuclear than very low.

On a related note, the effect of man made CO2 on climate change was grossly exaggerated.  ;-)

[SeanB]

How do you make a cheap, reliable, easy to use LH2 connector? It is cold enough that most metals are incredibly brittle, if it is H2 gas then the pressure is close to the limits for metals of manageable mass, and not to forget that Hydrogen tends to treat most metals as merely being an annoyance, migrating through it as if it is only a minor obstruction. Storing it long term in a cylinder means both the metal becomes brittle with time and after a few months half has escaped through it. Only thing worse is Helium, and at least that does not make steel brittle like glass.

[nctnico]

I'm wondering what the CO2 footprint is. Only 20% of the initial energy used to make H2 makes it to the wheels of an H2 powered vehicle.

Depending how you generate the electricity. If nuclear than very low.

They don't make H2 with electricity. Most is made from fossil fuels (notice the Shell logo on the pictures next to the article). It seems H2 is a byproduct of cokes ovens used at steel factories.
Using nuclear electricity is terribly inefficient. A nuclear power plant has an efficiency around 5% (AFAIK). The whole chain to the wheel may yield efficiencies below 1%. Maybe as low as 0.1%.

[niflheimer]

A nuclear power plant has an efficiency around 5% (AFAIK). The whole chain to the wheel may yield efficiencies below 1%. Maybe as low as 0.1%.

Afraid you are quite quite wrong . Typical efficiency for an entire unit is 30-35% .And that's for the common , single Rankine (steam turbine ) designs . If you switch to a combined cycle , with either a gas turbine or a different fluid like ammonia for a low pressure stage you can get up to 51% if all stars align. And all that without releasing one bit of CO2 ...

Also , you can produce hydrogen quite easily with a high temperature reactor ( either a gas core or one of the future 4th gen plants ) by thermal methods - and that will increase your efficiency as well since you reuse some of that waste heat.

[echen1024]

And nuclear is very clean. No CO2, no soot.

[Rufus]

A nuclear power plant has an efficiency around 5% (AFAIK). The whole chain to the wheel may yield efficiencies below 1%. Maybe as low as 0.1%.

Afraid you are quite quite wrong . Typical efficiency for an entire unit is 30-35% .

Depends how you define efficiency. Energy out as a percentage of energy available in the fuel is probably that low, not that is a useful measure of anything.

[NiHaoMike]

And nuclear is very clean. No CO2, no soot.

But wind, solar, and hydroelectric are just as clean and much safer.

[nctnico]

And nuclear is very clean. No CO2, no soot.

But wind, solar, and hydroelectric are just as clean and much safer.

Depends. According to the IPCC 'solar panel' electricity still emits 28grams of CO2 per kWh.

[lemmegraphdat]

Isn't natural gas the fuel and feedstock for hydrogen production? Sounds like a stupid waste.

[echen1024]

And nuclear is very clean. No CO2, no soot.

But wind, solar, and hydroelectric are just as clean and much safer.

But are not as efficient.