Hydrogen powered cars: Your news and views please

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#2257145 13-Jun-2019 07:50

GV27:

tdgeek:

Id like every roof in the country to have solar panels. Why not every car roof, bonnet, boot as well?

It's not economic to do, sadly. I know the Leaf has a solar panel, but it doesn't charge the traction battery, it just helps deal with drain on the 12v (as is my understanding).

There are currently a couple of cars in development with this, however even under best case scenarios, they're only capable of adding a mile or two of range a day.

Yep, solar isn't economical, which is a pity. A 300W panel is about 1.6m by 1.0 m, if there were two, or at leat, panel sizes that do 600W, if the car is outside at work all day thats maybe 5 x 550W if free charge. Or 12.4kW in a sunny week? Not worth it?

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#2257178 13-Jun-2019 09:24

tdgeek:

Yep, solar isn't economical, which is a pity. A 300W panel is about 1.6m by 1.0 m, if there were two, or at leat, panel sizes that do 600W, if the car is outside at work all day thats maybe 5 x 550W if free charge. Or 12.4kW in a sunny week? Not worth it?

You start hitting problems pretty quickly; the bigger the car, the bigger the panels, but the harder the drivetrain has to work. Plus there are very few 'flat' surfaces on cars and the time spent in an optimum position for collecting energy may be pretty small once relevant vehicle curvature gets taken into account. Either that or you have a boxy, un-aerodynamic car.

https://www.topgear.com/car-news/concept/solar-panel-car-charges-while-you-drive

We might get there. I'm not sure the process for manufacturing solar is any better than batteries but the scale of improvement is pretty staggering. $20k of rooftop solar five years ago can be bought for $6K installed today. You can stuff the same 'amount' of batteries into a 2014 Nissan Leaf but go 40% further than the original battery pack could.

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#2257220 13-Jun-2019 09:30

Aredwood:

Actually, quick refuelling is about the only advantage of hydrogen compared to EVs. And even then, if you are refuelling using gaseous H2. If you just connect the 2 tanks together, the pressures will equalise. And you will need to use a compressor to completely empty the supply tank and to be able to completely fill the receiving tank. Lots of electricity needed compared to a small pump that would be used to move petrol or diesel.

The boiling point of liquid hydrogen is -252deg Seriously cold cryogenic temp. While it has a very low "heat value" (energy content in relation to volume of gas at atmospheric pressure) So to transport or store large amounts of hydrogen. It has to be kept at very high pressures and / or very cold temperatures. Far more difficult than petrol or diesel - both of which can be transported and stored at room temp and atmospheric pressure. Perfect insulation for cryogenic temps is impractical. Therefore there will be losses due to heat absorption. Since H2 atoms are so small, they will migrate through most common materials. Which makes storage under pressure also difficult.

Lots of energy is required to either compress the H2 or supercool it. And even transferring H2 between 2 different storage vessels is also difficult as well. Therefore you end up needing to use lots of energy from outside sources, or you have to consume / loose quite a lot of the H2. Just to get it to the point of final use.

Safety - H2 has upper and lower flammability ranges of 4% and 75%. In comparison, Petrol has a range of 1.4% to 7.6%, Natural gas has a range of 5.4 to 17%. Therefore a hydrogen leak is far more dangerous than a petrol or natural gas leak. The need for extremely high pressure tanks for H2 storage. Also means that such tanks will need to be hydrostaticly tested every 10 years. (same as for LPG cylinders, diving air cylinders etc) This will be a significant extra cost that the pro hydrogen brigade has failed to consider. Yet is an important part of safely storing highly compressed gases.

As for off peak power generation. The cost of building a H2 production plant Vs the cost of electricity. It will likely be cheaper to build a smaller capacity H2 plant, and operate it 24/7. Than it would to build one that is twice the size, so it would only need to run for 12 Hours per day to obtain the same amount of H2. And due to storage difficulties, Production at the time of immediate usage / refuelling will likely still be cheaper. Therefore H2 production is unlikely to be an economic use of off peak power generation Vs peak time generation.

The ripple control system on hot water cylinders could easily be expanded to Ev chargers as well (to make Ev charging an interruptible load). And that would be by far the lowest cost method of integrating large amounts of solar or wind generation into the grid.

And fuel cells still produce lots of waste heat. Which is yet more losses, just to finally get to the end use point.

Hydrogen only make sense from an environmental point of view, if you assume that you have lots of extremely cheap electricity available, which is also fully renewable generated. But if such electricity is available, Then it is better to use it to replace fossil fuels in non transport use cases. And if we still have lots of renewable generation available. Then we should try to attract electricity intensive industries to NZ. More aluminium smelting. More server farms. More bitcoin mining, blockchains, AI supercomputing etc.

Consider how much power is used wordwide for Bitcoin mining alone. Then consider that most of that power is generated using fossil fuels. Bitcoin mining might be worse for the environment than gold mining. Especially when you allow for the coal mining and oil drilling in addition to the carbon emissions. And the embodied emissions to build the computers needed as well.

Edit to add.

Hydrogen also has a much faster flame front speed compared to Natural gas and petrol. Meaning a sudden ignition of a large amount of escaped H2 would be more of an explosion than a woosh. Again a bad thing in relation to hydrogen safety.

The extremely high pressures in H2 storage systems and tanks, means that the risk of compression ignition of H2 and any oxygen needs to also be managed.

Would a crash (say from something minor up to something more major) also mean needing to get a new Hydrogen tank in the car to make sure it's not compromised?

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#2257225 13-Jun-2019 09:34

GV27:

tdgeek:

Yep, solar isn't economical, which is a pity. A 300W panel is about 1.6m by 1.0 m, if there were two, or at leat, panel sizes that do 600W, if the car is outside at work all day thats maybe 5 x 550W if free charge. Or 12.4kW in a sunny week? Not worth it?

You start hitting problems pretty quickly; the bigger the car, the bigger the panels, but the harder the drivetrain has to work. Plus there are very few 'flat' surfaces on cars and the time spent in an optimum position for collecting energy may be pretty small once relevant vehicle curvature gets taken into account. Either that or you have a boxy, un-aerodynamic car.

https://www.topgear.com/car-news/concept/solar-panel-car-charges-while-you-drive

We might get there. I'm not sure the process for manufacturing solar is any better than batteries but the scale of improvement is pretty staggering. $20k of rooftop solar five years ago can be bought for $6K installed today. You can stuff the same 'amount' of batteries into a 2014 Nissan Leaf but go 40% further than the original battery pack could.

True.

frankv

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#2257233 13-Jun-2019 09:44

GV27:

frankv:

PhantomNVD: EV also have almost zero ‘servicing’ cost, and very little moving parts to go wrong (and need replacing) too.

I don't think this is quite true... whilst the motor and drive-train are relatively simple, there are still lots of moving parts on an EV... doors, wipers, suspension, windows, etc

And the large number of moving parts in an engine and gearbox are actually pretty much trouble-free for the life of the ICE. All you're saving is a couple of oil changes a year, and maybe a timing belt replacement.

Tell this to the owners of DSG gearboxes, which don't like creeping forward in traffic.

Or the clutches in manual cars.

Or the perscribed services that you have to get done to maintain a manufacturer warranty.

Total reliability is a really, really new thing in the world of motoring.

I've never claimed total reliability for ICE. There are always exceptions, but, generally speaking, cars don't break down due to ICE drivetrains wearing out. And IMHO the prescribed servicing (and the prices charged for it) is a rort by car manufacturers to be able to guarantee an income to the dealerships that they sell.

My father was an electrician, and regularly had callouts to replace burnt-out water pump motors in dairy sheds. So total reliability is also not a thing for electric motors.

All the other parts of the car are designed to have a life of about 15 years (or less), so over time you'll be left with a perfectly functional electric motor in a worn-out body. Will it be worth extracting that motor and putting it into another EV? I don't think so, so it'll get scrapped along with the battery and the rest of the car. And you can bet that whatever new technology (fuel cell or pure battery) is used to power the car, the implementation will be obsolete in 15 years. So increased longevity, as a by-product of better motor reliability, isn't actually a real benefit.

Yes, electric drive motors will be more reliable and need almost zero servicing. But battery EVs have expensive batteries which "wear out". I reckon ballpark-wise that the cost of the (EV+reduced servicing+electricity) will be about the same as the cost of an (ICEV+more servicing+fuel) over the vehicle lifetime. Especially if I buy a second-hand ICEV which has already depreciated rapidly, but is a long way from worn out.

But that's getting away from hydrogen-powered cars. Fuel cells wear out, but you can expect a life of over 15 years for typical car usage. Reading between the lines, it appears they need cooling systems (which can break). I expect that the smaller batteries in fuel cell powered cars will go through more charge-discharge cycles than in other EVs, and will therefore wear out faster. Maybe you'll need to replace the battery once in the life of the vehicle. Will the cost of (Hydrogen EV+one small battery+a bit of servicing+fuel) be less than the cost of the other vehicles? I don't think so. And with no fuel infrastructure in NZ, I wouldn't be leaping into buying a Hydrogen EV.

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#2257261 13-Jun-2019 10:17

It's still a bit early to say how well and how long EV batteries hold up. In the case of a Leaf with no thermal management of the battery we know that life isn't too great. On the other hand we have Tesla's with proper battery thermal management driving every day between LA and Las Vegas that have more than 200,000km on a single battery pack and another Taxi example in Finland with 400,000km on the battery. Both are still in the 90-95% range for remaining capacity.

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#2257275 13-Jun-2019 11:05

Obraik:

It's still a bit early to say how well and how long EV batteries hold up. In the case of a Leaf with no thermal management of the battery we know that life isn't too great. On the other hand we have Tesla's with proper battery thermal management driving every day between LA and Las Vegas that have more than 200,000km on a single battery pack and another Taxi example in Finland with 400,000km on the battery. Both are still in the 90-95% range for remaining capacity.

Nissan are their own worst enemy in terms of batteries. Even when the batteries work, the controllers designed to measure them don't 😄

WyleECoyoteNZ

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#2257421 13-Jun-2019 14:22

I've said it before and say it again, EV work if you have the facility's at home to charge every night.

But:

What about those that park on the road, maybe outside there house\home, maybe not, how would they recharge the vehicle?

What about those who rent? Sue you can recharge off a standard wall socket, but I'd wager that not many landlords would be keen on the outlay for a home fast charger.

So isn't in these above scenario's a Hydrogen powered vehicle a better option, rather than a Pure battery only EV?

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#2257440 13-Jun-2019 14:50

WyleECoyoteNZ:

So isn't in these above scenario's a Hydrogen powered vehicle a better option, rather than a Pure battery only EV?

Only if you can actually get hydrogen.

And I think it would have to be enormously subsidized to make it competitive with electricity. http://www.fuelcell.co.uk/fuel-cell-costs/ shows it as being 20 times as expensive as BEV, 10 times as expensive as petrol, and twice as expensive as hydrogen ICE (fuel only costs).

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#2257452 13-Jun-2019 15:10

WyleECoyoteNZ:

So isn't in these above scenario's a Hydrogen powered vehicle a better option, rather than a Pure battery only EV?

If you don't have a power socket handy to your kerbside, you're probably not going to have a million-dollar filling station either.

Ge0rge

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#2257453 13-Jun-2019 15:12

GV27:
WyleECoyoteNZ:

So isn't in these above scenario's a Hydrogen powered vehicle a better option, rather than a Pure battery only EV?

If you don't have a power socket handy to your kerbside, you're probably not going to have a million-dollar filling station either.

The filling station doesn't need to be on your curbside though - in the same way we don't all have a petrol station at the end of our drive.

GV27

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#2257455 13-Jun-2019 15:17

Ge0rge:
GV27:

WyleECoyoteNZ:

So isn't in these above scenario's a Hydrogen powered vehicle a better option, rather than a Pure battery only EV?

If you don't have a power socket handy to your kerbside, you're probably not going to have a million-dollar filling station either.

The filling station doesn't need to be on your curbside though - in the same way we don't all have a petrol station at the end of our drive.

....and there are such a thing as public electric chargers too, and private networks where you can pay to fast-charge a car, in addition to almost every wall outlet in the country and caravan parks.

Delphinus

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#2257460 13-Jun-2019 15:33

WyleECoyoteNZ:

What about those that park on the road, maybe outside there house\home, maybe not, how would they recharge the vehicle?

What about those who rent? Sue you can recharge off a standard wall socket, but I'd wager that not many landlords would be keen on the outlay for a home fast charger.

I've borrowed a friends EV for a week. Charging at home off a standard wall socket was 100% fine for the typical driving most people are doing. It's so easy, you go home, plug in, next morning car is full.

Obraik

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#2257466 13-Jun-2019 15:57

WyleECoyoteNZ:

I've said it before and say it again, EV work if you have the facility's at home to charge every night.

But:

What about those that park on the road, maybe outside there house\home, maybe not, how would they recharge the vehicle?

What about those who rent? Sue you can recharge off a standard wall socket, but I'd wager that not many landlords would be keen on the outlay for a home fast charger.

So isn't in these above scenario's a Hydrogen powered vehicle a better option, rather than a Pure battery only EV?

Most people that have a car use it to either go to work and/or go shopping. It's not unfeasible for a work place to install charging stations and it's becoming more common for shopping destinations to install chargers in their carparks. A number of malls have done so, as has New World and The Warehouse. By the time you finish work or a shop you should be fully charged.

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WyleECoyoteNZ

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#2257469 13-Jun-2019 16:15

GV27:

Ge0rge:
GV27:

WyleECoyoteNZ:

So isn't in these above scenario's a Hydrogen powered vehicle a better option, rather than a Pure battery only EV?

If you don't have a power socket handy to your kerbside, you're probably not going to have a million-dollar filling station either.

The filling station doesn't need to be on your curbside though - in the same way we don't all have a petrol station at the end of our drive.

....and there are such a thing as public electric chargers too, and private networks where you can pay to fast-charge a car, in addition to almost every wall outlet in the country and caravan parks.

Yes, but a public charger is going to be, a) busy and have queues and b) take a decent amount of time.

I'm going to use Wellington here as an example, but if I lived in Mt Victoria, Mt Cook or Newtown, chances are my car will be parked curbside. Due to these suburbs close proximity to the CBD I could either walk or cycle to work. If the car is only being used weekends, the last thing I want to be doing is spending 30-40 minutes charging the car before I can go anywhere.

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