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Are they cheaper? Even over 1M miles or whatever a truck engine is expected to go?
Yes, significantly so. Hydrogen fuel cells have a much shorter lifespan and higher manufacturing/replacement cost than lithium ion batteries. The compressed gas tanks are also very expensive and have a limited lifespan (albeit a relatively long one, compared to the fuel cells).
And as hydrogen scales up, it’ll get cheaper. It’s currently a bit more expensive than gas (about 3-4x), but that’s with hydrogen transported from some plant somewhere. If it’s locally generated from solar, it’ll probably be quite a bit cheaper.
Market rate hydrogen is currently about as cheap as it’s possible to get, because it is almost exclusively from fossil fuel sources which are gradually winding down.
Locally produced electrolysis hydrogen suffers from very low efficiency rates; about 2/3rds of the power used to produce the hydrogen is lost in the process. Assuming you don’t have an enormous overabundance of power being generated, it’s more efficient to store the power locally in batteries (which don’t have to be lithium ion if it’s for static storage; other chemistries become competitive if they don’t need to move around) than it is to store it as hydrogen. And if you’re generating a huge overabundance of power such that throwing 2/3rds of it away seems sensible, in most cases the question would be why you don’t make a grid connection and feed in anyway (extreme remote locations notwithstanding).
Git is the underlying code management and version control system. It can be used directly, and also forms the backend to a number of other systems.
Code “forges” are platforms which integrate a version control system (like git), a code repository (a file server), and front end utilities.
Some git forges are open source, others are proprietary. Certainly with the open source ones, but also with the proprietary ones in some cases, you can either self-host or use a hosted service.
GitHub is a proprietary forge, and GitHub.com is the company’s fully hosted service. They’re now owned by Microsoft.
Gitlab is an open source forge. Gitlab.com offers a hosted service, but many projects self-host.
Forgejo is a fork of Gitea which is a fork of Gogs. These are all also open source. As far as I know, neither Forgejo nor Gogs offer a hosted version, but Gitea does.
A few other notable forges include GNU Savannah (open source), Bitbucket (proprietary), Sourceforge (proprietary), Launchpad (open source), Allura (open source).
At the end of the day, they all do the same thing. They have different feature lists (especially around some of the project management and user interaction side), different user interfaces (some are shinier and more modern, others more minimalist), and different communities and support models. You choose that one that works best for your needs.
GitHub is probably the most feature-rich (and/or bloated) of them. GitLab is competing in the same space, and self-hosted GitLab seems to be something of a sweet spot for many projects that want a premium experience without needing to use a proprietary Microsoft product. I don’t have much experience with Forgejo or Gitea. The rest tend to exist in their niches.