156
Hydrogen vehicles in Denmark left without fuel as all commercial refuelling stations shuttered
(www.hydrogeninsight.com)
this post was submitted on 21 Sep 2023
156 points (95.3% liked)
Fuck Cars
9682 readers
1294 users here now
A place to discuss problems of car centric infrastructure or how it hurts us all. Let's explore the bad world of Cars!
Rules
1. Be Civil
You may not agree on ideas, but please do not be needlessly rude or insulting to other people in this community.
2. No hate speech
Don't discriminate or disparage people on the basis of sex, gender, race, ethnicity, nationality, religion, or sexuality.
3. Don't harass people
Don't follow people you disagree with into multiple threads or into PMs to insult, disparage, or otherwise attack them. And certainly don't doxx any non-public figures.
4. Stay on topic
This community is about cars, their externalities in society, car-dependency, and solutions to these.
5. No reposts
Do not repost content that has already been posted in this community.
Moderator discretion will be used to judge reports with regard to the above rules.
Posting Guidelines
In the absence of a flair system on lemmy yet, let’s try to make it easier to scan through posts by type in here by using tags:
- [meta] for discussions/suggestions about this community itself
- [article] for news articles
- [blog] for any blog-style content
- [video] for video resources
- [academic] for academic studies and sources
- [discussion] for text post questions, rants, and/or discussions
- [meme] for memes
- [image] for any non-meme images
- [misc] for anything that doesn’t fall cleanly into any of the other categories
Recommended communities:
founded 1 year ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
Today, green hydrogen is essentially an expensive, low-efficiency battery.
That could change with future work on making more efficient hydrolysis, but today, the numbers really don't work out on green hydrogen vs alternatives like lithium ion or overhead wires for busses.
But a hydrogen battery has much much better specific energy than lithium ion. So you can have a much longer range.
Hydrogen is very light, so the energy per kilogram is quite high.
However, hydrogen is also naturally not very dense. Hydrogen at 1 atmosphere has a tiny fraction of the energy of a similar volume of batteries. Pressurized hydrogen is similarly dense to a battery, and liquid hydrogen is about twice as dense.
So to make hydrogen dense, you need a very thick, heavy tank to hold the pressurized hydrogen. That significantly cuts into your weight advantages.
Add to that, fuel cells are very inefficient at converting hydrogen to usable electricity.
Maybe I'm missing other conversion factors, but hydrogen has a volumetric energy density of 9MJ/L which is about 2.5kWh/L compared to about 1.7kWh/L for the newest Tesla batteries. So hydrogen is more energy dense than batteries even by volume.
Aren't those the numbers for liquid hydrogen?
Oh maybe. That would make extra complications. Looks like low pressure gas is 0.5 kWh/L which is more in line with what you were saying.