The case for transitioning away from (was: banning) diesel: It hurts you and especially your kids.

Forums › Transport (cars, bikes and boats) › The case for transitioning away from (was: banning) diesel: It hurts you and especially your kids.

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#1607305 9-Aug-2016 22:56

MikeAqua:

Ultimately I think HVs will beat EVs.

Hydrogen is >100MJ/kg. It's abundant. Thermodynamics are on your side. Maybe a little too much on your side! The challenge is containment. Solar power can be used to produce it from water.

Batteries right now are <5 MJ/kg. Thermodynamics are not on your side.

The greatest medium term hope for battery powered EVs is that manufacturers develop standardised swappable main batteries. Then drivers could use service stations that swap the battery over while they have a coffee and snack.

Hydrogen may have the highest specific energy of any fuel ( 141.86 MJ/kg). A super lightweight fuel is good for the likes of rockets, but not so useful in road cars (it's not like a full tank of petrol has a material impact on most cars).

On the other hand Hydrogen as a gas has a super low Energy Density (0.01005 MJ/L), this is way too low to be useful, so it needs to be either cryogenically cooled to -252.9 °C make it a liquid (BMW did this with a this car with a tank insulated using high vacuum). (downside is cryogenic cooling this cold is expensive, also the equipment is too big to fit in a car, so they relied on allowing the hydrogen to boil to keep cold - means if you fill the tank, and leave the care for 12 days, all your fuel will have evaporated...)

Modern Hydrogen car's have forgone the cryogenic approach, in favor of massive, super high pressure cylinders. The Toyota Mirai uses 87.5kg's of (high tech carbon fiber) tanks to store just 5kg of hydrogen. If you add this weight in, it drops your effective specific energy to just 7.7 MJ/kg. Still way better than current batteries at sub 0.5 MJ/kg...

I think the major issue with Hydrogen is the cost of production and distribution of the fuel.

Regarding Battery swapping, look up "project better place" (failed large scale battery swap scheme).

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#1607378 10-Aug-2016 07:58

In the interest of trying EVs out first hand, I took up the opportunity to drive the Renault Kangoo ZE. Apart from looking a little ridiculous, which was a fault of the car not what was powering it, it wasn't too bad. I managed 90 km of night driving, with the heater on and a cellphone fast charging in the power socket, with 25 km remaining. I don't think this is the best example of EVs, but I can see what others mean about driving, it's smooth and pleasant for sure. This one, perhaps a little underpowered and quirky, might not be ideal for mainstream yet, but if faster chargers and bigger batteries come along then it could replace some small delivery vehicles. I thought I'd drop in to Sylvia Park to charge it a bit while I had a coffee, but unfortunately they hadn't unlocked the station yet, should've gone to Mcds! It can be a little daunting watch the battery diminish going up the motorway towards Panama Road, which was early on in my journey, but it encouraged me to maintain constant speeds and smooth driving. For this model, the instant you take of the accelerator the regenerative braking kicked in, which was quite harsh, and took some getting used to, for me, and the cars behind me.

I will be happy to get back behind the security of fossil fuels for now, but can see there's some progress in the right direction.

gzt

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#1608536 10-Aug-2016 13:13

That automatic braking sounds a bit weird. But then again, French engineering tends to have a few differences and it is a commercial delivery vehicle.

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#1610399 12-Aug-2016 04:25

MikeB4:

I absolutely agree that the internal combustion engine is nearing end of life not for only heath reason but for planetary health. However I do not believe plug in EV or Hybrid EV is the answer in the long term. These simply replace where the damaging energy production is done.

The long term is HFC vehicles, these have very low impact on the environment mainly from the elephant in the room, batteries, but these impacts are very much a reduced risk and impact, as the technology evolves they will be even better.

<snipped>

Yes I know this is nearly 2 weeks old but I somehow ended up on page 3 and saw this and while I saw some later discussions of hydrogen production and transport, I didn't see this in particular challenged. I don't really understand how you can say "simply replace where the damaging energy production is done" but treat hydrogen needed for HFC as being any different. As discussed later, there's no magic solution to producing hydrogen. Ultimately it takes energy so if you can use that energy to produce hydrogen, you can likely use it to produce electricity.

It's true that a lot of electricity production at the moment is fossil fuel based and dirty but there's no reason why hydrogen production is going to be immune from that nor is it automatically clear that diverting your energy resource to produce hydrogen would be a better outcome than producing electricity. (In other words, if you e.g. use solar to produce your hydrogen, you could alternatively use solar to produce electricity. For that matter rather than sending your hydrogen all over the place to be used for cars, you could use it to produce electricity if it doesn't just make sense to avoid the hydrogen step entirely.)

The questions as discussed later in the thread related to stuff like the efficiency of producing electricity and transmitting it to your house or whereever to ultimate charge up your vehicle vs efficiency of producing hydrogen and transmitting it all over to be used to fuel up your vehicle. Plus the costs and complexities of producing a HFC vehicle vs a plug in EV (especially considering the bigger battery needed for the EV). Plus the big issue of range of the plug in EV. And the myriad of other issues later discussed in the thread (and those not discussed).

In other words, hydrogen in our context is ultimately a method of transferring and storing energy not a source of energy so it's not somehow automatically better than electricity from an environmental context, no matter how much of our current electricity worldwide is produced from coal. Perhaps HFC will be important or even take over but it surely should have nothing to do with plug in EVs "replac(ing) where the damaging energy production is done" and HFCs not doing so.

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#1610400 12-Aug-2016 06:08

we have a much better chance of running cars on bullsh!t than hydrogen

MikeAqua

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#1610653 12-Aug-2016 12:38

Scott3:

I think the major issue with Hydrogen is the cost of production and distribution of the fuel.

I think the key is to distribute production. A hydrogen tanker truck is a terrible idea from an efficiency and safety perspective.

Where as water and electricity is widely available. Electrolysis of water produce hydrogen and oxygen. Oxygen is useful a product as well - engineering, medicine etc.

I've been trying to find some info on the energy requirements and relate this back to solar power, roof area etc but it's not easy to do.

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Scott3

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#1610990 12-Aug-2016 22:01

MikeAqua:

Scott3:

I think the major issue with Hydrogen is the cost of production and distribution of the fuel.

I think the key is to distribute production. A hydrogen tanker truck is a terrible idea from an efficiency and safety perspective.

Where as water and electricity is widely available. Electrolysis of water produce hydrogen and oxygen. Oxygen is useful a product as well - engineering, medicine etc.

I've been trying to find some info on the energy requirements and relate this back to solar power, roof area etc but it's not easy to do.

Hydrogen production techniques are already mature (it is a readily available gas used in reasonable volumes in industrial applications). Cheapest way to make it at the moment is by steam reforming of methane or natural gas. Given the technology is already mature, this is unlikely to change unless we have a scientific breakthrough. Having a little electrolysis plant (and associated equipment such as compressors, massive storage tanks (or cryogenic gear)) at every petrol station seems like a pipe dream to me. If we are going to use natural gas, why not just use it directly, and skip the hydrogen step.

I guess you will have noticed there is some resentment amounts alternative fuel supporters about hydrogen. This is due to the appearance that the auto industry has used it to avoid scrutiny about the future of it's vehicles. They were always 5-10 years away from going mainstream "don't worry the car that's only emissions is water vapor is coming". When the Tesla came onto the market, Toyota rushed to release it's Hydrogen car. The result is disappointing. Car's performance low, fuel cost's are about the same as a normal car (not 1/3 like an electric car), and getting fuel (in California where the cars are available) is a major issue. The Hydrogen station have had major reliability issues some down for months, a major issue given how far apart they are. Many are only able to 1/2 fill cars (only fill to 35bar, not 70bar), dropping the hydrogen cars range from 500km (in the Mirai) to only 250km. This is not much further than the range of the cheap electric cars (and well less than the range of a Tesla), but without the convenience of being able to charge at home, and wake up every morning with a full battery, and pre warmed car to start the day.

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#1611027 13-Aug-2016 08:59

kotuku4:

joker97:

Linuxluver:

And we will be happy to use hydrogen tanks made in China........because they'll be cheaper, right? :-(

It could be that the only way that EV uptake works is that China start making them to drive the price down ... ?

They are hard out making electric vehicles in China and Korea, and they have high demand for cleaner transportation.

https://en.wikipedia.org/wiki/Electric_vehicle_industry_in_China

Just read this http://www.stuff.co.nz/motoring/news/83102826/taking-on-tesla-chinas-wm-motor-sees-mass-market-electric-cars

dwl

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#1611114 13-Aug-2016 15:49

MikeAqua:
Scott3:

I think the major issue with Hydrogen is the cost of production and distribution of the fuel.

I think the key is to distribute production. A hydrogen tanker truck is a terrible idea from an efficiency and safety perspective.

Where as water and electricity is widely available. Electrolysis of water produce hydrogen and oxygen. Oxygen is useful a product as well - engineering, medicine etc.

I've been trying to find some info on the energy requirements and relate this back to solar power, roof area etc but it's not easy to do.

Unfortunately production of hydrogen on site using water and electricity is about 3x less efficient than storing the same energy in a battery and powering an EV. A recently commissioned hydrogen refilling station using electrolysis in London cost GBP1m, will only refuel 16 vehicles a day, can only fill three cars after each other then needs a long pause and each kg of hydrogen costs GBP10 (5kg fill is GBP50). An efficiency comparison is at https://speakev.com/threads/new-hydrogen-refuelling-station-opens-that-can-supply-16-cars-a-day.17193/page-3#post-288252

If batteries continue to improve there seems little point in hydrogen for smaller vehicles but possibly a place in heavy where need more energy density. The well to wheel efficiency of hydrogen remains low with some reports putting it under 10%.

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#1612406 16-Aug-2016 12:25

Nissan are bringing to market (in the USA) the first commercially produced variable compression ratio turbocharged petrol engine vehicles. Nissan nomenclature is "VC-T". Engine uses an adjustable lever/cam system between the conrod big end and crankshaft, compression ratio can be instantly adjusted between 8.1 and 14.1.

Claimed benefits for the 4 cylinder 2 litre unit are:

Similar torque to common-rail turbo diesel engines.
Similar power to conventional petrol ICE V6 of approximately 3.5 litres capacity.
Much more simple to achieve emission standards (presumably compared to diesel).
~ 35% improved efficiency/economy than current ICE petrol engines.

First vehicle to use the new engine will be an Infiniti "medium sized" crossover vehicle - "medium" being US medium - it's a large vehicle by NZ averages, current models use up to a 3.7 litre petrol V6.

If successful this tech will no doubt filter down to be used in other vehicles.

MikeAqua

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#1612494 16-Aug-2016 13:57

dwl:

If batteries continue to improve there seems little point in hydrogen for smaller vehicles but possibly a place in heavy where need more energy density. The well to wheel efficiency of hydrogen remains low with some reports putting it under 10%.

In the medium to long term; efficiency is a much easier thing to improve than enthalpy ... thermodynamics always win.

Mike

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#1612556 16-Aug-2016 16:19

joker97:
we have a much better chance of running cars on bullsh!t than hydrogen

Are you talking about raw BS, like you hear at the pub, or refined BS, like the media reporting from politicians? (joking)

“We’ve arranged a society based on science and technology, in which nobody understands anything about science technology. Carl Sagan 1996

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#1613470 17-Aug-2016 21:37

Orange are pleased with the demand for their electric "terminal truck" range. These are used at ports, large warehouses and inter-modal container handling sites.

One less place / context where diesel is needed. They report they have demonstrated major savings on the sites that have already implemented them.

http://www.truckinginfo.com/channel/electric/news/story/2016/08/orange-ev-launches-class-8-electric-truck.aspx

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#1613957 18-Aug-2016 20:18

http://i.stuff.co.nz/motoring/news/81647671/nissan-develops-major-breakthrough-in-engine-technology

Linuxluver

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#1613986 18-Aug-2016 21:26

joker97: http://i.stuff.co.nz/motoring/news/81647671/nissan-develops-major-breakthrough-in-engine-technology

Yeah....saw that. A nice improvement in efficiency.

Too late for me, though.....I now know first hand how much better it is to not use petrol at all. Loads of torque, cheap power and no emissions at all.

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