Biodiesel
Should be used for Trucks, Semi's and other large vehicles
Clean Coal
BS made up by the cola lobby.
Electric Cars
within a few years this will be totally practical for every behicle under 5k pounds.
Ethanol
Corn ethanol has only limited use, but is getting more credit than it deserves from the corn lobby. Sugar ethanol is much more promising, problem is only countries like Brazil have enough sugar to do it right. In the USA it could be an additive to Biodiesel but I'm not sure about that.
Geothermal Energy
meh
Hybrid Vehicles
hopefully only temporary, or could be practical for "mid size" trucks, larger than 5k pounds, but smaller than the big semi's
Hydrogen Vehicles
dangerous, and not as practical/cost effective as just straight electric.
Nuclear Power
good until we can get the entire grid powered by wind and solar
Ocean Thermal Energy Conversion
waste of time
Power from Flowing Water & Waves
waste of time unless your in an area that has no wind and never gets sun (not likely)
Solar Energy at Home
will only be mildly practical once solar farms are in wide use
Solar Farms
most promising source of endless energy. still need to increase the efficiency a tad, but we are close.
Wind Power at Home
same as home solar, mildly practical.
Wind Farms
great, but even the international org promoting windfarms admits that at best only 6% of the worlds energy will come from wind. Past that its just not effective, and if you get to 10%, the towers will actually have a very negative effect on the worlds climate.