Battery-electric vehicles are about 2-3 times more energy efficient than hydrogen fuel cell vehicles, according to VW [0]
> Doesn't making a battery require mining a ton of metals?
Less, actually - a bit under half a tonne of metal in a Tesla battery pack, most of it nickle (as of 5 years ago) [1]
> How efficient is the recycling of spent batteries?
Roughly 92% [2] and improving. A car purchased today would have its battery recycled in ~10 years, so it'll be higher by then.
[0] https://insideevs.com/news/406676/battery-electric-hydrogen-...
[1] https://electrek.co/2016/11/01/breakdown-raw-materials-tesla...
[2] https://electrek.co/2021/08/09/tesla-battery-cell-material-r...
How much more mining is needed to produce a battery pack than a fuel cell? How much more waste metal is there? Are there any chemical pollutants in either system?
Both systems are going to have different ratios between Bad Stuff and efficiency and my unqualified guess is that hydrogen _might_ be better.
Right. When comparing objects of similar complexity, cost of the object is generally pretty proportional to bad-stuff-produced, with exceptions for unpriced externalities (carbon emissions being a big one, and mining or refining in low-responsibility jurisdictions being another). The carbon emissions of battery pack manufacturing are small[1] relative to lifetime emissions from an ICE car, not totally sure for FCEV.
> Both systems are going to have different ratios between Bad Stuff and efficiency and my unqualified guess is that hydrogen _might_ be better.
I couldn't find anything specific to FCEV, but my gut instinct is that FCEV would be dramatically worse - hydrogen is reformed from natural gas, necessarily entailing carbon emissions. If you're going to release the CO2 from natural gas anyway, might as well do it by burning in a high-efficiency turbine and use the energy to charge your BEV at high end-to-end efficiency. Or if you're going to consider "green" hydrogen, might as well use the renewable energy to directly charge a battery, at 3x higher efficiency.
[1] https://theicct.org/sites/default/files/publications/EV-life...
A lithium battery is nearly 100% efficient.
They both run through an inverter and electric motor so those efficiencies are the same.
Efficiency is how much power is put in vs how much you get out.
A fuel cell is efficient compared to pretty much every other form of generating electricity from energy stored in a fuel that we know of.
Why would you do that? You could argue energy density, but looking at current fuel cell vehicles like the Mirai shows the have only a slim advantage in range dues to the weight of the fuel cells, high pressure tanks and tractions batteries and extra structure to protect the tanks.
The electrons in the battery are very light and energy dense but the battery to hold them and return them as useful current is not, same for hydrogen.
What hydrogen fuel cell car is not a proof of concept?
>>The Plasma Kinetics founder said that his company’s solution weighs only one-third of batteries for the same amount of energy.
To compare to battery storage, one needs to compare both the storage and electrical conversion solution, so in this case, is the [weight of the storage cassette] + [weight of fuel cell making electricity] less than [weight of batteries yielding same KWh of electricity]?
If they can make that work, they are on to something. I hope they are, but we really need to know the full picture.
BEVs are winning at the momemy not because they're efficient, but because the cost/benefit is finally coming out ahead due to advances in battery technology.
But BEVs don't fully cover all use cases. It is telling that the first commercial truck manufacturer to release a full electric truck has also invested billions into hydrogen. BEVs can certainly handle a lot of usecases, but continuous usage at high power levels isn't one of them, even at theoretical energy densities.
I suspect it is the same for the other percentages thrown around on that diagram. ... and why doesn't the H2 vehicle do regenerative braking?
This is applied to all steps, electrolysis, compression, transport, and fuel cell conversion back to electricity.
Current fuel cells cannot put out enough burst power to acceleration nor can they accept electricity in reverse to generate hydrogen so all current fuel cell vehicles use a traction battery that is charged by the fuel cell, they are basically series hybrids. They also typically have lower acceleration because the small traction battery + fuel cell cannot supply as much power as a much larger full EV battery.