Biofuels and Hydrogen-powered vehicles also are of interest.
"Biofuels" are just hydrocarbons by another name. Instead of extracting the raw Oil from the ground and refining it, we take waste from crops and refine that. The problem of course is that it's lacking the few million years of compression that gravity provides to make the fuel dense, so you get far less energy densit unless you refine it further to compress it, which in turn costs more. Example is Ethanol only has about half the energy density of regular gasoline. Hydrogen is even worse. You can get plenty of Energy if you burn it (H2 + O2 = H20 and a *** ton of thermal power) but storage and transportation is extremely dangerous. A tank of pure H2 is literally a bomb. Fuel Cell usage is a little different though, less direct chance at explosion though you still need to store and transport a large quantity of Hydrogen gas. The cell itself is using an expensive catalyst (usually Platinum) to enable the chemical reaction that's energy output is in potential difference (it separates a material into Ions and electrons) instead of direct thermal heating.
Video of what happens when a small lithium battery short circuits
https://www.youtube.com/watch?v=SMy2_qNO2Y0
Now imagine that multiplied by a few thousand or so.
We'll be using Hydrocarbons for a very long time. They are simply too energy dense with a low requirement to implement. The good news is just because we use Hydrocarbons doesn't mean they need to originate from refined crude oil. We can create Hydrocarbon fuel easily enough from the raw ingredients of Carbon, Hydrogen and some Oxygen. The Ocean has far more then enough dissolved Carbonic Acid or Bicarbonate (that's the EVIL Carbon the Ocean's storing) to use as Carbon feed stock. Hydrogen is even more plentiful in that same Ocean. The only missing ingredient is energy, lots of energy. We need to spend slightly more energy then the hydrocarbon fuel will store due to inefficiencies in the process. This energy would come from an extremely high capacity source similiar to what Aluminum plants need. Because of this requirement Nuclear plants are particularly appealing as they need a large source of H2O nearby for cooling purposes. Basically we turn the power from the nuclear plant into stored chemical energy that's transported and released upon combustion. Hydrocarbon as a liquid battery.
Funniest part is that it's "carbon neutral". The CO2 released from the combustion eventually goes back into the Ocean where it's extracted again as Carbonic acid. It's a giant circle. The US Navy's already researched and developed the technique including a demo reactor. They plan on using it to fuel the Navy without needing large tanker ships to transport all that fuel around. Large ships already have Nuclear reactors on board so they plan on using excess base load power to create this fuel and storing it for use in fighter aircraft or fueling a nearby conventional ship.
Now hear all the regressive liberals gnash their teeth about such a solution.