Zythryn wrote: ↑
Sat Oct 17, 2020 4:57 am
A very detailed look at hydrogen and where it Is, and isn’t a clear winner.
https://about.bnef.com/blog/liebreich-s ... 1LzOnWk67M
As you look at role of clean hydrogen in this future net-zero energy system, you should notice something striking. None of the compelling use cases for hydrogen are widely distributed. No massive demand for hydrogen filling stations, nor hydrogen boilers, no hydrogen-based heat in most industries. The overwhelming bulk of its use will be in the chemicals industry and the power system.
A good article, and I'm in general agreement with most of it. I do have some disagreement in a few places, e.g.:
However, as an energy storage medium, it has only a 50% round-trip efficiency – far worse than batteries. As a source of work, fuel cells, turbines and engines are only 60% efficient – far worse than electric motors – and far more complex.
True, but efficiency alone isn't enough, and he ignores capability differences, although he alludes to them here:
What this means is that hydrogen’s role in the final energy mix of a future net-zero emissions world will be to do things that cannot be done more simply, cheaply and efficiently by the direct use of clean electricity and batteries
Indeed. The efficiency of the typical car ICE is around 20%, with Toyota claiming the Atkinson cycle ICE in the current Prius to be a world leader at 40 or 41%, yet that hasn't stopped ICEs from dominating BEVs. H2/FC efficiency should be compared with ICEs and fossil fuels as well as batteries.
Re transport, he goes way over the top in the following:
There are three commercial hydrogen models on the market: the Toyota Mirai, the Hyundai Nexo and the Honda Clarity. They have no more range than comparable sized battery electric vehicles (BEVs).
Only true for the Mirai, which is the oldest of the three, and not true for the others.
They are no lighter. They have less luggage space (those pressurized hydrogen tanks).
Luggage space is true for the sedans, esp. the Clarity, but not the Nexo. And all three use the previous gen. of stack with about 3kW/l power density rather than the current gen which is about 4 kW/l. I suspect they're all lighter by a few hundred lb , but haven't checked.
They have half the acceleration and a lower top speed. And they have more moving parts, meaning higher maintenance costs. If none of that has not dissuaded you from buying one, there’s the price: up to 20% higher than an equivalent BEV; if you want a funny-looking two-seater for the same monthly lease cost as a Tesla 3, there’s always the Riversimple Rasa.
While the accel comment is currently true, that's a design decision. As for price, please compare the costs of BEVs with 366 or 380 miles of range.
When it comes to refueling, most BEV drivers do it at home or work, eliminating regular trips to the gas station. On the odd longer trip, rapid-chargers can add 200 miles of range – about as far as most people want to drive between bathroom breaks – in 20 minutes. Concerns about lack of on-street and motorway charging are like turn-of-the-millennium concerns about internet bandwidth: would video-on-demand ever work? Short answer, yes.
Here he's really losing his objectivity. Precisely how many models of BEV can add 200 miles of range in 20 minutes? "Most" people only want to drive 200 miles between stops? That's less than 3 hours at 70, 2.5 at 80. I guess that's why virtually every ICE in the market has over 300 miles of range. And if 200/20 is good, then 366-380/5 or even 312/5 is far better.
I guess the lack of local on-street and motorway charging in my area and on the trips I take (see the Bolt topic this week) are figments of my imagination, and that apartment dwellers have nothing to be concerned about. 'Eventually' the problem will be solved, eventually meaning multiple decades.
From a public policy perspective, the real killer for H2FC cars is their wind-to-wheel (or solar-to-wheel) inefficiency. Driving a small family car 100km, whether H2FC or BEV, uses 15kWh of motive energy at the wheels. For the BEV, taking into account losses on the grid and in the battery cycle and drive train, that translates into a need to generate 25kWh at the plant where the electricity is generated. The equivalent for the H2FC car, given losses in electrolysis, compression, transport, storage and reconversion of hydrogen, is at least 50kWh. Put simply, hydrogen cars are half as efficient as BEVs – and there is no reason in physics to think that will change.
Again, what's the well-to wheel efficiency of fossil-fueled ICEs? Again, where possible the best all-around mix given current capabilities is a PHFCEV.
It’s not just cars, either. The underlying physics and economics are no different when it comes to urban buses, delivery vans, commercial vehicles, service and industrial vehicles. In fact, pretty much anything that does not regularly drive over 300 miles without stopping is better as a BEV than as an H2FC.
You can quibble about the exact breakpoint range and I'd put it lower, but no argument that for the commercial BEV types above, they are, within their operating range if weight isn't an issue the way to go, assuming LCC are equal or better.
Surely, when it comes to longer distances, hydrogen finally comes into its own? . . . .
Not necessarily, says Auke Hoekstra, a researcher at Eindhoven Technical University. First, he found that 90% of 40-ton trucks entering and leaving the Port of Rotterdam drive less than 750km per day. After optimizing the truck’s drag, that means a 1MWh battery – weighing 6 tons based on today’s technology, but on track to decrease to 3 or 4 tons within the decade. What he also found was that replacing the internal combustion drive train with electric motors would save up to 3 tons, meaning that in terms of payload, between BEVs and traditional trucks, it’s almost a wash. As for fueling, as long as trucks have drivers, they need to stop for breaks – 45 minutes per 4.5 hours in the EU.
Golly, we only need to move U.S. ports to Rotterdam, shrink the of the U.S. and Canada to fit, and legislate and enforce
European driver rest periods in these countries, then BEVs break even. Oh, plus another decade of likely but not certain battery improvements. If they do, great. You can read what he has to say about electrifying highways and see if you think that would be cheaper here, given the much greater size of the country.