ENV100Y5 Lecture Notes - Lecture 55: Wave Power, Developing Country, Woody Plant

• School: UTM
• Department: Environment
• Course: ENV100Y5
• Professor: Barbara Murck

Document Summary

Chapter 16 - fossil fuels. Tuesday, february 23, 2016. We use a variety of energy sources. Oil and natural gas (petroleum) Alternative fossil fuels (tar sands, oil shales, shale gas) Biomass energy (fuelwood, ethanol, energy- from- waste) Energy resources can be renewable, inexhaustible, or non- renewable. Fossil fuels are non- renewable they are replenished, not on a humanly timescale. Mineral resources 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 wattis one joule/second (1 j/s) A joule is 0. 239 cal. A terawatt is a trillion (1012) watts. Current human energy use: 500 exajoules/yr. 500 x 1018 joules per year = 16 terawatts. 500 x 1018 joules per year = 16 terawatts: most energy comes from solar, then wind. It takes energy to make energy. Energy returned on investment (eroi) = energy obtained/energy invested.