This includes wood, fossil-fuel, nuclear, geothermal, hydroelectric and tidal energies.
This leaves solar and wind energies (which last is indirect solar energy for the most part).
Both should be exploited in as decentralized a fashion as possible, for robustness and to evade monopoly.
The problems with solar energy include efficiency, storage and (in photocells) use of rare minerals (with their environmental and monopolistic problems).
An interesting spin-off from fusion research suggests an admittedly "Big Power" solar-energy system which might obviate all three.
The Tokamak nuclear-fusion-reactor design involves in its classic form a toroidal (donut-shaped) fusion-plasma circulating within magnetic confinement.
But cannot a lower-energy, toroidal electron-plasma (or even proton-plasma), not necessarily magnetically-confined, be accelerated by collected and concentrated sunlight?
Call such system a "Solamak".
Solamaks will be more efficient than most solar conversion tchnology, will store energy in the form of plasma momentum to the limit of confinement (a proton-plasma might be better here), and will not require rare minerals (or even, very possibly, metals or glasses--see below).
Furthermore, much of the needed engineering (e.g. electrical conversion) has already been accomplished, in the work on Tokamak designs.
Solamaks might be used not only in high-solar regions but also placed on ships or barges, transported to the Equator (and even sub-Equatorial regions of problematic oceanic heating) to be charged by collectors there, and then returned to where they are needed, including being transferred in port to train-car for transport inland.
Solamak design allowing acceleration of its plasma by external application of electricity would allow wind energy to be tied in as well.
And with mechanomerically-selected-enzyme-catalyzed synthesis of diamond and other materials, including organic superconductors, all synthesized from organic chemical industrial feedstocks themselves synthesized from enzyme-catalyzed carbon-dioxide-capture (using photo- or electroenzymes or both), such technology might be the greenest "Big Power" of all (but might not such system be made home-sized?).
At any rate, such technology should be either government- or non-profit-run, to forestall the theft and monopolization of and price-gouging for natural resources long characteristic of the "energy industry".
Keywords: energy, fossil fuels, geothermal, Green, Green Switch, greenhouse gases, hydroelectiricy, Solamak, sustainability, tidal power, Tokamak, wind energy, wood