Energy, Power, and Climate Change 8.2 World Energy Sources  We can divide all of the world's energy sources into two groups: sun-derived, and non-sun-derived. S OURCE 1 : S UN-DERIVED  The following hierarchy of energy sources shows how the sun is the ultimate source of much of our energy: Sun-Derived Energy Sources FuelsNon-fuels  Coal  Oil  Gas  Wood  Biomass  Solar Energy  Hydroelectric  Wind  Wave  Photovoltaic FYI: Fuels are indirect sources of energy - they must be "burned" to produce useable energy. FYI: Non-fuels are direct sources of energy - they can be used immediately as useable energy. FYI: The energy from both fuels and non-fuels is usually converted (via one or more stages) into the final form of energy (for instance, electricity). Don't forget that each conversion entails a certain percentage of the original energy lost. Recall the Sankey diagrams.

Energy, Power, and Climate Change 8.2 World Energy Sources  We can divide all of the world's energy sources into two groups: sun-derived, and non-sun-derived. S OURCE 2 : N ON-SUN-DERIVED  There are not many energy sources that do not come in some way from the sun's radiant energy. Non-Sun-Derived Energy Sources FuelsNon-fuels  Hydrogen  Uranium  Tidal  Geothermal FYI: Chemical fuels that are non-sun-derived include rocket fuel and oxidizer, MRE heating packets, and other chemically-activated heating units (for example, first aid cooling packs).  Chemical FYI: Chemical non-fuels that are non-sun-derived include fuel cells, where hydrogen and oxygen are combined to produce electricity directly.

Energy, Power, and Climate Change 8.2 World Energy Sources  Most of our energy comes from fuels. Here is the energy yield of various fuels: FuelFuel TypeEnergy Density (MJ/kg) ProtonsNuclear300,000,000 Uranium-235Nuclear90,000,000 PetrolFossil46.9 DieselFossil45.8 BiodieselFossil42.2 Crude OilFossil41.9 CoalFossil32.5 SugarFossil17.0 WoodFossil17.0 Cow DungFossil15.5 Household WasteFossil10.0 FYI: We have been working on FUSION reactors for years, but have still not perfected them to the point of being able to use them on a commercial basis. FYI: We have had working FISSION reactors for years, and have thousands of them currently on commercial lines.

Energy, Power, and Climate Change 8.2 World Energy Sources W ORLDWIDE C ONSUMPTION OF E NERGY S OURCE OF E NERGY P O W E R w a t t s O I L % G A S % C O A L % H Y D R O E L E C T R I C - 6 % N U C L E A R - 6 % A L L O T H E R S - 1 % THE FOSSIL FUELS 87%

Energy, Power, and Climate Change 8.2 World Energy Sources R ENEWABLE S OURCES OF E NERGY (PERCENTS) S OURCE OF E NERGY P O W E R w a t t s S O L A R % G E O T H E R M A L % B I O F U E L S % W I N D %  The buzzword among the greenies is renewable sources of energy - which are inexhaustible sources of energy. FYI: Don't forget, these energy sources are part of the "all others - 1%" from the previous slide. There is obviously room for contribution from the renewables, but the question remains - how significant can these ever become in the grand energy picture? OIL GAS COAL HYDROELECTRIC NUCLEAR ALL OTHERS

Energy, Power, and Climate Change 8.2 World Energy Sources  Electricity is such a convenient energy form (for both usage and transportation), we should also look at the worldwide sources of electrical energy: W ORLDWIDE S OURCES OF E LECTRICITY (PERCENTS) F O S S I L F U E L S 6 5 % F OSSIL F UELS 65%