this post was submitted on 08 Jun 2024
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micromobility - Ebikes, scooters, longboards: Whatever floats your goat, this is micromobility

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Ebikes, bicycles, scooters, skateboards, longboards, eboards, motorcycles, skates, unicycles: Whatever floats your goat, this is all things micromobility!

"Transportation using lightweight vehicles such as bicycles or scooters, especially electric ones that may be borrowed as part of a self-service rental program in which people rent vehicles for short-term use within a town or city.

micromobility is seen as a potential solution to moving people more efficiently around cities"

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This past week, I attended the Micromobility Europe event in Amsterdam, where I saw many familiar company faces and several...

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[–] [email protected] 10 points 6 months ago (3 children)

I wonder if the water is drinkable, that would be pretty cool if your bike also produced hydration on rides so you wouldn't have to carry extra water.

[–] [email protected] 7 points 6 months ago* (last edited 6 months ago) (1 children)

The hydroride site says the green bottle contains 20g hydrogen, that might make 180g water, but is still not a lot if you're thirsty. But can 20g of Hydrogen really take a bike 60km ?

[–] [email protected] 13 points 6 months ago* (last edited 6 months ago) (1 children)

Maybe? Warning Half-asses napkin math here but there are 286 KJ in a gram of hydrogen. So that 20 grams has 5720 KJ which converted to Watt hours is 1589 Wh. From my googling hydrogen fuel cells are 40 - 60 percent efficient. So half that to 750 Wh. Which is comparable to most e-bikes rated for 20Km of range. There are some issues with hydrogen. Converting water to hydrgron is only 70-80% efficient and converting that hydrogen to electricity is 30-60 percent efficient. Compare that to li-ion battery which can be charged at close to 99%. That mean hydrogen waste so much more electricity. Which is why I'm a hydrogen hater. I much prefer putting solar energy directly into batteries instead of the converting it hydrogen and back again at great lost.

[–] girsaysdoom 2 points 6 months ago (1 children)

Your hydrogen efficiency estimates are probably pretty close to what this bike can do. The lithium ion comparison is missing some losses, ~90% efficiency from voltage boost converter. Also, the hub motor/speed controller both add another 75% efficiency to the equation but this applies to both so we can negate it.

As for being a hydrogen hater, what did hydrogen ever do to you? I think we'd all prefer a solid state solution that would minimize losses but we don't have enough battery infrastructure to accommodate all of our needs. Sure, hydrogen is not the panacea for fossil fuels or lithium batteries in cars but there are good uses for it. I think Hydrogen can potentially be a good replacement fuel for large shipping vessels like ships and trains, since size requirements aren't as much of a factor, or used in grid storage as a long term or spillover storage for renewable energy when battery infrastructure is at full utilization and other means aren't available.

[–] [email protected] 2 points 6 months ago (1 children)

I didn't think about hydrogen powered shipping container ships. That sounds like a good use case.

My main issue with hydrogen is that most of it is produced using some natural gas / fossil fuel thing I don't understand. AKA Dirty hydrogen. Producing hydrogen using green tech is super inefficient compared to storing green energy in batteries. Personally, I think better battery tech like sodium Ion that uses cheap and recyclable materials are the better option for most applications.

I do have a personal conspiracy theory that fossil fuel is pushing for hydrogen to slow green tech epically since the cheap way to make hydrogen is with fossil fuels.

Another thing about hydrogen is storage and transportation. To store it long term you need to cool it a liquid form which is really hard to do. Also, current hydrogen fuel cell are low efficiency and low power density. That's why the toyota miria uses a fuel cell to charge a battery which powers the car.Tthe fuel cell can't put out high current.

Most of what I know about hydrogen tech came from the aging wheels video about Mirai. So I might be super wrong about everything. I do recommend giving it a watch though: https://www.youtube.com/watch?v=rtZQLUtckS4

[–] girsaysdoom 2 points 6 months ago

You're definitely not wrong. Gray hydrogen currently is the most common source, which is a byproduct or an intended product of petroleum cracking. This also is probably a reason why most petroleum companies chose to research hydrogen in the 2000s/2010s rather than battery or other renewable technologies, since it fits nicely in their existing pipelines.

For storage, I'm pretty sure you can keep it at atmospheric pressure and temperature if space isn't an issue, but to actually fit it in a vehicle you'd probably have to use one of the techniques you mentioned.

The Mirai's issues seem to be that it was just a foothold for consumer hydrogen without anything really backing it. You could almost say the same about EVs/PHEVs 15 years ago and look at them now.

Honestly though, if we are able to scale up sodium batteries, grid storage and train usage might be moot. Ships could probably still use it as an alternative to diesel though.

[–] [email protected] 3 points 6 months ago (2 children)

You would lose electrolytes though, you would need to bring them on longer trips.

[–] [email protected] 5 points 6 months ago

Doesn't look like it produces a lot either, so yeah, I guess it could only supplement your water supply.

[–] [email protected] 3 points 6 months ago

You'd have to sweat a lot for that to be a factor. Not that it is irrelevant, but humans can drink distilled water just fine. In fact, there are regions, where bottled water is almost exclusively distilled.

So as long as you don't plan to participate in the Tour de France, you'll be fine.

[–] [email protected] -1 points 6 months ago (2 children)

When hydrogen reacts with oxygen it produces pure water. Pure water is quite reactive and will leave chemical burns on your skin. The reason is that pure water will try its best to absorb minerals, etc. And your body contains a lot of minerals and other stuff. Never drink chemically pure water!

[–] [email protected] 1 points 6 months ago (1 children)

Pure water is not going to burn you and you can even drink it (though, over time, it can leach minerals from you but then again so do carbonated beverages). People buy distilled water all the time.

[–] [email protected] 1 points 6 months ago (1 children)

Distilled water is not pure water.

[–] [email protected] 1 points 6 months ago* (last edited 6 months ago) (1 children)

What do you mean by "pure water" then? What exactly are you referring to?

Edit: Ok, it looks like judging by your other post, you're referring specifically to type II deionized water. That is not really what people immediately think of when you say pure water. Also, it's not going to burn you unless you boil it.

[–] [email protected] 1 points 6 months ago (1 children)

What else can you think of seeing "pure"? If it's not chemically pure, then it's not pure.

[–] [email protected] 1 points 6 months ago

Literally any purified water or other variety of distilled water would probably come to mind for most people.

[–] girsaysdoom 1 points 6 months ago (1 children)

Where did you hear this? You're talking about distilled/unmineralized water not an acid.

[–] [email protected] 1 points 6 months ago

You can see a guy drinking pure water here https://youtu.be/FElDa62zwwE