unksol :
Someone Somewhere :
The problem with hydrogen cars isn't just the fuel - the actual fuel cells that convert 2H2 + O2 > 2H20 (looks better with the right subscripts) to release energy are ridiculously expensive and inefficient. Sure, you might be able to make the hydrogen, but using it for anything but heating is pretty expensive and difficult.
Fuel cells are not that expensive and costs will drop. Storing and transporting hydrogen in a car is though. And fuel cells are much more efficient than an ICE. 50% at least. As long as you are getting the hydrogen for cheap/free it's a fine idea, just not in cars. Probably never in homes directly either, not enough biomass. But "central" ones running of leaf pickup and organic garbage and crop waste? Sure. anything is better than ethanol
Labs at one of the tech universities in Germany have been using fuel cells to run a few buildings for years. Why? Well. Cause tech university lol. but guess what the efficiency goes to when ALL that "waste" heat is dumped into your radiant heating system snd hot water and you dont need electric or gas boilers anymore?
Exactly right! Even if this tech went only to power heat (and AC/refrigeration) sources it would take a huge load off of the overall power grid. We could go with solar to power things like home electronics, and then move to a cheap technology like this to cover things like heating and cooling. Heating and cooling is some 40+% of most people's power needs (heater, AC, water heater, oven, stove, clothes dryer, fridge) and all of it can be run efficiently on flammable gasses directly, it does not need to be converted to electricity to be a huge help to the power grid.
On top of that you are right on about the efficiency of vehicles. We are currently at ~50% efficient with the burning of gasoline for propulsion... we could go much higher than that, but the problem is that to get gasoline to burn more efficiently requires the operating temperature to raise significantly, which then becomes a bit of a dubious physics problem for something as small as a car (like the whole car would melt and burn). No matter how you slice it, once you have energy out of an ICE you have already lost 50% of the possible power from the system. The gains we are seeing in fuel efficiency are due to better drive trains, lighter weight materials, better gasoline, less wind resistance, etc, but nothing recoups that energy lost at the start of the process.
The nice thing about moving to electric power for vehicles is that the 50% limitation does not apply in the same way. My understanding (and I could well be wrong on this) is that we are still loosing some 50% of the potential power in an electric system, but most of this is an energy transfer and storage issue. Once you have the electricity inside the vehicle you have very little loss going from the battery to the motors, heater, AC and stereo (though more modern/efficient/powerful onboard computer solutions would be a plus!). Plus you get to recapture energy that would have been lost in things like braking, and you are not chained to a singular power source (anything that can be converted to electricity becomes a potential fuel). The trick is finding better ways to convert heat/light/material into electricity, and then more efficient ways to converting that electricity into a stored state for use in a battery, and there is progress being made on those fronts already. The other issue is getting material costs down and drive range up so that people can afford and use said electric/hydrogen vehicles, but that is again mostly an energy storage issue as the battery is the expense that dictates the car's higher price point.
Also, efficiency is not always required for all systems (*shock!*). If this new way of producing hydrogen is sufficiently plentiful and cheap then it does not need to be particularly efficient in order to be useful. All that it needs to do is be clean (lack harmful byproducts), cheap, and have a similar usable energy density to other energy storage solutions (such as Gasoline or lithium-ion batteries). So long as it meets those requirements then it can be 20% efficient and still be a better solution than traditional technologies, and it will get better as the technology matures. From what I understand about fuel cells (which is admittedly surface level) the hard part has always been hydrogen production, and that once you had that then you would have an energy storage system that puts things like batteries and gasoline to shame. Either way you are not dealing with the byproducts and politics (middle east) of gasoline, or the EV range and politics (china) involved with battery production. Not saying that those are the only things to consider when choosing a new energy technology, but they do go a long way at making fuel cell tech look pretty good.