how are you applying concepts like “energy-dense” to, say, sunlight or geothermal?
Energy density refers only to fuels and energy storage media and doesn’t have much to do with grid-scale investment, although it’s important for things like transport where you have to move your power source along with you. (Short version: hydrocarbons beat everything else, although batteries are getting better.)
The usual framework for comparing things like solar or geothermal energy to fossil fuels, from a development or policy standpoint, is energy return on investment. (Short version: coal beats everything but hydroelectric, but nuclear and renewables are competitive with oil and gas. Also, ethanol and biodiesel suck.)
Energy density refers only to fuels and energy storage media and doesn’t have much to do with grid-scale investment, although it’s important for things like transport where you have to move your power source along with you. (Short version: hydrocarbons beat everything else, although batteries are getting better.)
The usual framework for comparing things like solar or geothermal energy to fossil fuels, from a development or policy standpoint, is energy return on investment. (Short version: coal beats everything but hydroelectric, but nuclear and renewables are competitive with oil and gas. Also, ethanol and biodiesel suck.)