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Hydrogen vs. Battery Buses: A European Transit Reality Check

cleantechnica.com

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Re: Hydrogen vs. Battery Buses: A European Transit Reality Check

#121

Post by HPsquared »

smeeger wrote: post #93
martinald wrote: post #7

Earlier quoted context omitted.

While I agree with you; just to be clear it's not "slightly" beef up the local transformer. If you imagine a medium sized depot with 50 buses stabled at any one time, and 300kW chargers (I believe you could go higher), that's 15MW peak which is not trivial to add in many cities overnight. You really need some sort of HV connection for that kind of load, the existing local LV distribution grid isn't going to handle it…

a lot of people like to laugh very, very loudly at the idea of upgrading the grid to handle EVs. simply remind them that at one point in time there was no grid at all. the grid is not some magical entity that cant be changed

It's a bit like the difference between building a new house, vs renovating an old one. Different skills are required and the renovation project can actually be more complex than new build.

Re: Hydrogen vs. Battery Buses: A European Transit Reality Check

#122

Post by philjohn »

filmor wrote: post #109
philjohn wrote: post #92

Earlier quoted context omitted.

Yes - but Hydrogen vehicles have not proven to match or even beat EV's in a lot of key metrics that matter. The biggest one is efficiency. 40% efficient is one figure I saw, versus 80% for EV's. Yes, you can refill quicker, but time to "refuel" EV's is dropping precipitously as well, and it's just all around safer than tanking around highly combustible liquid gas.

How is that efficiency calculated, respectively?

https://www.sciencedirect.com/topics/engineering/fuel-cell-e...

I believe all Hydrogen vehicles are using proton exchange membranes still, which have roughly 40-50% efficiency.

And that's before you take into account that even the most cutting edge hydrogen refining processes are around 70% efficient.

So 1kWh of energy input (electricity) will net you 3X the motive power when used directly in a BEV than first being coverted to hydrogen, and then converted back into electricity.[1]

[1] 0.5*0.7 = 0.35.

Re: Hydrogen vs. Battery Buses: A European Transit Reality Check

#123

Post by philjohn »

nautilius wrote: post #113
philjohn wrote: post #92

Earlier quoted context omitted.

Yes - but Hydrogen vehicles have not proven to match or even beat EV's in a lot of key metrics that matter. The biggest one is efficiency. 40% efficient is one figure I saw, versus 80% for EV's. Yes, you can refill quicker, but time to "refuel" EV's is dropping precipitously as well, and it's just all around safer than tanking around highly combustible liquid gas.

Efficiency is the standard red herring of the battery crowd - if efficiency was the prime motivation, we would all be driving bicycles and SUV or sportscars would not exist. What are your other metrics? It’s an electric drivetrain with all advantages, but with the range of a gasoline car. Refueling cNG or LNG is standard in Europe, LH2 works just fine. Google “burning Tesla” for that ridiculous take on why batteries…

Except it's efficiency for the same class of vehicles we're talking about, so a bike is an apples to oranges comparison.

Proton Exchange Membrane is 40-45% efficient. Generating hydrogen from electricity is 70% efficient - meaning for a kWh of input electricity you get 3x the motive power from a BEV.

Then rolling out a refuelling network, with the high pressure tanks and expensive delivery mechanism, will cost far more than installing EV chargers - and that's before we even get onto the CURRENT penetration of EV chargers vs Hydrogen filling stations today (16 in the UK, 54 in the ENTIRE US, and not growing).

Hydrogen might be the solution to emissions from haulage, but BEV's are more than good enough compared to the ICE cars they're replacing for 99.9% of motorists needs. Yes, I'm ignoring the "I need to drive 1000 miles without stopping for fuel, rest, using the bathroom, come back when an EV can do THAT" people.

And on burning EV's, they catch fire at rates 20x lower than ICE cars, and LFP chemistry is far more resistant to thermal runaway.

Now lets talk cost - over the life of the car the BEV will be cheaper to run. Filling a Mirai in the UK will cost you around £90 for 400 miles of range. Charging my EV6 from 0 to 100 will cost me £5.50 for 300 miles of range. We're talking near orders of magnitude difference in cost per mile here - it's almost an unfair advantage that you can charge an EV at home off peak for next to nothing.

Re: Hydrogen vs. Battery Buses: A European Transit Reality Check

#124

Post by mschuster91 »

kleiba wrote: post #83
spacebanana7 wrote: post #61

Earlier quoted context omitted.

Still, their point was directionally correct. London has 1397 electric buses and Moscow has over 2300. https://en.m.wikipedia.org/wiki/Low_emission_buses_in_London https://en.m.wikipedia.org/wiki/Electric_buses_in_Moscow

Germany has this recurring fixation on hydrogen for whatever reason. Even when Tesla had already long hit the mainstream market, German car manufacturers were still arguing against EVs in favor for hydrogen-powered cars that would theoretically be vastly superior. Well, we all know how that turned out for Mercedes, BMW, and the so on.

> Germany has this recurring fixation on hydrogen for whatever reason.

Hydrogen would enable a lot of very rich and powerful businesses to just pivot their business model a bit: the fossil fuel industry would have a destination for "grey hydrogen", pipeline owners could repurpose natural gas pipelines and bunkers for hydrogen, you'd still need refineries, tanker trucks to refill gas stations, you'd still need a nationwide network of gas stations in the first place...

In contrast, electric cars cut out a lot of the middlemen - once you got the car and a solar panel on your roof, you don't need _any_ of these industries any more. And you can't have that.

Re: Hydrogen vs. Battery Buses: A European Transit Reality Check

#125

Post by credit_guy »

Hydrogen is difficult to store. But it enjoys the square-cube law. If you increase the size of a tank by a factor of 2 in all 3 dimensions, the capacity increases by a factor of 8, but the cost only by a factor of 4.

Hydrogen has some huge advantages over other green options. But, also some huge disadvantages. If you want to diminish the disadvantages, you need to exploit the square-cube law, and that means you need huge scale.

In other words, hydrogen is a non-starter for cars. It has a very low chance of success for buses, but not zero. It could work very well for trains. And it could work extremely well for electricity generation at city scale.

Re: Hydrogen vs. Battery Buses: A European Transit Reality Check

#126

Post by eptcyka »

londons_explore wrote: post #71
7e wrote: post #47

Earlier quoted context omitted.

The bus is constantly starting and stopping. Regen doesn't recapture it all. Power isn't the issue, energy is. Also, current hybrid busses with not-so-heavy batteries weigh about 15 tons without cargo. You are way off.

This math is for future busses designed for city use - so batteries will be much smaller and therefore lighter, and the bus construction itself will be much lighter because, as you point out, with a city bus pulling away ~5 million times in its lifespan, the cost of energy lost when stopping and pulling away far exceeds the cost of upgrading the frame to aluminium and other weight saving measures.

Buses have been designed for city use for ages. The double deckers are not designed for motorway use.

Re: Hydrogen vs. Battery Buses: A European Transit Reality Check

#127

Post by adrian_b »

7e wrote: post #47
londons_explore wrote: post #30

Earlier quoted context omitted.

0.7 m/s^2 is a typical acceleration for a city bus - most people won't fall over whilst standing at that acceleration. A city bus perhaps holds 50 70kg passengers = 3.5 tons of cargo, and a lightweight bus design is perhaps 6.5 tons (typical bus=10 tons). Total = 10 tons. Peak Power required to accelerate 0.7 m/s^2 up to 30 mph = 93 kilowatts. Which is car territory. The cheapest tesla model 3 has a 208 kilowatt moto…

The bus is constantly starting and stopping. Regen doesn't recapture it all. Power isn't the issue, energy is. Also, current hybrid busses with not-so-heavy batteries weigh about 15 tons without cargo. You are way off.

Regen can capture during stopping most of the energy consumed during starting, if well designed, while in a non-electric bus all energy is lost.

The mass of the bus does not matter, only the energy lost due to mechanical friction or electrical resistance, both of which increase much more slowly than the mass for bigger buses.

Re: Hydrogen vs. Battery Buses: A European Transit Reality Check

#128

Post by perilunar »

misswaterfairy wrote: post #101
m4rtink wrote: post #2

I'm not really sure there is any place for a discussion - you would need a whole new infrastructure for hydrogen powered buses, while keeping a lot of the downsides of fossil fueled air breathing vehicles (eq. air filters filters regardless of if you burn the hydrogen or use it in fuel cells). With battery buses - you might need to slightly beef up the local transformer and installs some new wires and that's it. Or e…

> you would need a whole new infrastructure for hydrogen powered buses, while keeping a lot of the downsides of fossil fueled air breathing vehicles (eq. air filters filters regardless of if you burn the hydrogen or use it in fuel cells) Australia kind-of already had 'hydrogen' infrastructure and supply chains already, in LPG or 'autogas'. LPG (or dual petrol/LPG) used to be a popular option for small vehicle fuel in…

> many Aussies have to drive in rural and remote areas where EVs just aren't practical

I’m currently in rural NW NSW, and it seems to me that BEVs would be ideal out here once they get a bit cheaper. Plenty of sunlight. Plenty of rooftop solar — every second house and farm shed has solar panels already. Powering farm vehicles from local solar instead of imported diesel seems logical and inevitable really.

Re: Hydrogen vs. Battery Buses: A European Transit Reality Check

#129

Post by xbmcuser »

credit_guy wrote: post #125

Hydrogen is difficult to store. But it enjoys the square-cube law. If you increase the size of a tank by a factor of 2 in all 3 dimensions, the capacity increases by a factor of 8, but the cost only by a factor of 4. Hydrogen has some huge advantages over other green options. But, also some huge disadvantages. If you want to diminish the disadvantages, you need to exploit the square-cube law, and that means you need…

Storage is just part of the problem with hydrogen. The process of generating hydrogen has never been cost-effective. It's just not possible to make hydrogen cheaply right now. Solar energy, on the other hand, gets so cheap that it won't make sense to produce hydrogen with it, then transport it to a city and convert it to electricity. We should just send the electricity directly.

Re: Hydrogen vs. Battery Buses: A European Transit Reality Check

#130

Post by adrian_b »

class3shock wrote: post #10

From the article, "A second obvious theme is the prevalence of hydrogen buses in industrial regions and cities that bought into the hydrogen for energy narrative that’s falling apart now. Cologne, Aberdeen, Bolzano, Groningen/Drenthe, and Wuppertal are all trying to be hydrogen valleys, centers of the hydrogen economy’s industry. That’s going badly because it was always a bad idea, devoid of thermodynamic and economi…

I fail to understand how using elemental hydrogen for storing energy has ever sounded like a good idea for anyone.

What sounds like a good idea is using fuel cells instead of ICEs, but using hydrocarbons as fuel, not dihydrogen (also solid carbon is a possible fuel).

The use of hydrocarbons can be carbon-neutral and sustainable, by making them from carbon dioxide and water.

There have been various experiments with fuel cells using other fuels than dihydrogen, but the main roadblocks have been a lower power at a given size than with pure hydrogen and the need for more frequent maintenance, besides the main disadvantage common to all kinds of fuel cells for now, high cost, due to expensive catalysts or to components such as separators that must be replaced frequently.

Nevertheless, we know that it is possible to make cheap and performant fuel cells, as demonstrated by any living being that breathes air.

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