Energy densities of various substances and/or reactions is pretty fascinating concept.
Some of the most interesting energy analysis I've come across (Vaclav Smil and David MacKay especially) describe energy in terms of area: what are the comparable land areas which would have to be dedicated to specific sources or forms of energy or fuels, and how do those compare? One of Smil's descriptions of petroleum wells is "punctiform", which I love. A hole in the ground, only about 20 cm in diameter, can provide years to millennia of human energy output, per day.
1 litre of oil is equivalent to about 3 days of human energy output (at 3,000 kilocalories/day).
1 gallon of oil is eqivalent to about 11 days of human energy.
One of the oldest oil wells in production (the First Oil Well of Bahrain) produced 80,000 barrels of oil per day initially. That's over 1,000 years of human energy equivalent.
By comparison, the yeild of current biomass production is far, far less. The difference, of course, is that oil is biomass, accumulated, converted, and concentrated over hundreds of millions of years. We're consuming it at > 5 million times its rate of formation. (See Jeffrey S. Dukes, "Burning Buried Sunshine" (2003).)
In terms of radioactivity, the net metabolic rate of the Sun's core is lower than that of a human, measured in energy/mass. Solar metabolism is closer to that of reptiles, about 1/5 of mamallian metabolic rates.
Chemical energy is less productive than the most effective nuclear transitions, but its shear abundance and ease of utilisation tends to weigh in its favour.
Some of the most interesting energy analysis I've come across (Vaclav Smil and David MacKay especially) describe energy in terms of area: what are the comparable land areas which would have to be dedicated to specific sources or forms of energy or fuels, and how do those compare? One of Smil's descriptions of petroleum wells is "punctiform", which I love. A hole in the ground, only about 20 cm in diameter, can provide years to millennia of human energy output, per day.
1 litre of oil is equivalent to about 3 days of human energy output (at 3,000 kilocalories/day).
1 gallon of oil is eqivalent to about 11 days of human energy.
One of the oldest oil wells in production (the First Oil Well of Bahrain) produced 80,000 barrels of oil per day initially. That's over 1,000 years of human energy equivalent.
By comparison, the yeild of current biomass production is far, far less. The difference, of course, is that oil is biomass, accumulated, converted, and concentrated over hundreds of millions of years. We're consuming it at > 5 million times its rate of formation. (See Jeffrey S. Dukes, "Burning Buried Sunshine" (2003).)
In terms of radioactivity, the net metabolic rate of the Sun's core is lower than that of a human, measured in energy/mass. Solar metabolism is closer to that of reptiles, about 1/5 of mamallian metabolic rates.
Chemical energy is less productive than the most effective nuclear transitions, but its shear abundance and ease of utilisation tends to weigh in its favour.