battery: noun ( pl. -teries) a container consisting of one or more cells, in which energy is converted into electricity and used as a source of power.
Mineral oils found as deposits in the earth's crust are roughly analogous to finding batteries charged with energy left lying around by a long-dead civilization.
Hydrogen, wood, flywheels, gasoline, capacitors, a hot rock, kerosene, Uranium, and an ice cube are all different ways of storing energy's potential in a form that can conveniently be used after a period of delay.
This shouldn't be surprising but I'm surprised how often I see people focus on a particular type of stored energy without considering others simply because the energy takes a different form.
I think we can all agree that burnable wood, which was one of the human race's first and most frequently used energy stores to be harnessed, isn't the most suitable battery on a global scale with 6.5 billion humans needing convenient and portable power. Of course, it does the job for a good portion of our population but there are the negative consequences of increased pollution, increased carbon dioxide output, and deforestation.
So which of these batteries could we choose to supply all human portable power needs? The answer is that none of them are universally suitable. We will have to continue to use all of these for the indefinite future.
One thing has become clear to even optimists is that the oil age is coming to a close
With that in mind the primary question before us is how do we generate the power that goes into these batteries?
IMHO - I think we'll slowly transition from natural gas and coal to nuclear, wind, hydro, wave, and, of course, solar.