Originally Posted by
fairflyer
There are quite a raft of regional airliners either being retrofitted with hydrogen fuel-cell-powered electric motors or complete clean-sheet designs under development now, especially in the 19-50+ seat market. However, take for example Universal Hydrogen's retrofitted ATR-72 and a good ten or so seats are replaced with containerised hydrogen tanks, so the revenue per seat mile will be somewhat diminished. Things like the Dornier 328eco are looking good (retains turbine engines but using alternative fuels), Heart Aerospace, Zero Avia and others, but can't imagine certification by 2025 and entry into service immediately thereafter. Also costs will be interesting - leasing an old Dash-8, ATR or Dornier, or perhaps say an old CRJ or EMB-145 is going to be a lot cheaper than anything new and/or expensively retrofitted. It's exciting to see, but perhaps people need to be a little more realistic on timescales?
Unless there is a massive breakthrough in battery technology, battery powered aircraft will never be viable for other than short hops - simply too much mass in the needed batteries. Similarly, the difficulties with H2 storage mean it's unlikely to ever be viable for other than short range operations.
Various methods of creating carbon neutral synthetic kerosene (e.g. biofuels) hold far more long term promise (my personal favorite is using algae as a feedstock for biofuels - raising algae can use existing waste products and takes only a small fraction of the area that corn/soy/etc. based biofuels require). All this stuff with batteries and H2 for anything other than short range is mainly political posturing and/or investment cons.