Many, maybe even most of the alternatives to fossil fuels that have been or are now being proposed are for the most part technically feasible.
- Is hydrogen as a fuel feasible? Yes.
- Are electric vehicles feasible? Absolutely. You can run now to the dealer and buy a LEAF or a Tesla.
- Could we generate, say, 30% of our electricity with solar and wind? Don't even doubt it.
- Will fusion power become a reality? You can take that to the bank.
- What about tidal power? Yes, it works, in France, Canada and elsewhere.
- Compressed air cars? Also, fully feasible and the "battery," in other words the air tank, can be recharged forever.
- Geothermal? Just ask Iceland.
So, if we have all these feasible and wonderful alternatives to fossil fuels, how come they barely make a dent in the global energy market?
Ah, the reason is that to compete and win technical feasibility is not enough. To displace fossil fuels the alternatives need to be cheaper. If, for example, the kWh of electricity (in the USA) can be produced for 6 cents from natural gas, THAT is the technology to beat. If a company brings something to market that can produce that same electricity for, say, 10 cents, then it is almost certainly going to fail.
The same with electric vehicles. For them to truly compete, their purchase price would need to be the same or lower than a gasoline or diesel car and, more important, their cost per kilometer driven (including the battery replacement cost) should be the same or lower than that of a conventional automobile. Even if both these requisites were met, the EV is still not as convenient as an internal combustion vehicle.
Alternative energy reporting is, for the most part, deceiving. For example, renewable lobbyists tend to report "installed capacity" rather than actual energy production.
If we show actual energy production we can see fossil fuels almost completely dominate the market and this is not due to cute political tactics but because they are (relatively) cheap, abundant, convenient, etc.