ENV100Y5 Lecture Notes - Lecture 50: Developing Country, Oil Sands, Wave Power
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ENV100Y5 Full Course Notes
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Unconventional fossil fuels (oil sand; shale gas; etc) Biomass energy (fuelwood, ethanol, energy from waste, etc) Energy resources can be renewable, inexhaustible, or nonrenewable. Fossil fuels are nonrenewable - they are replenishable, but not on a humanly accessible timescale. Material resources (e. g. , minerals) can be recycled but energy resources cannot, because of the second law of thermodynamics. We are not in danger of running out of energy in the earth system. A watt is one joule/second (1 j/s) A terawatt is a trillion (1012) watts. 500 x 1012 joules per year = 16 terawatts. What is in question is the availability of energy that is available, economically affordable, socially acceptable, and environmentally benign. Energy returned on investment (eroi) = energy obtained/energy invested. Higher erois: we receive more energy than we invest. Ratios decline when we extract the easiest deposits first and then must work harder to extract the remaining reserves. Developed nations consume more energy than developing nations.
