In 2008 the World Energy Usage was 474 exajoules (5×10^20 joules). 85% was derived from non-renewable fossil fuels.
World Energy Usage By Graph:
Oil 37%, Coal 25% and Gas 23% — are fuels formed by natural resources such as anaerobic decomposition of buried dead organisms. These fuels contain a high percentage of carbon and hydrocarbons.
–Wikipedia: Fossil Fuel
Nuclear 6% — is power (generally electrical) produced from controlled (i.e., non-explosive) nuclear reactions. Commercial plants in use to date use nuclear fission reactions. Electric utility reactors heat water to produce steam, which is then used to generate electricity.
–Wikipedia: Nuclear Power
Biomass 4% — is biological material derived from living, or recently living organisms, such as wood, waste, and alcohol fuels. Biomass is commonly plant matter grown to generate electricity or produce heat. For example, forest residues (such as dead trees, branches and tree stumps), yard clippings and wood chips may be used as biomass. However, biomass also includes plant or animal matter used for production of fibers or chemicals. Biomass may also include biodegradable wastes that can be burnt as fuel.
Hydro 3% — is power that is derived from the force or energy of moving water, which may be harnessed for useful purposes.
Solar Thermal 0.5% — is used for water heating, space heating, space cooling and process heat generation. The primary solar energy is solar water heating. Solar water heating systems are generally composed of solar thermal collectors, a fluid system to move the heat from the collector to its point of usage.
–Wikipedia: Solar Energy
Wind 0.3% — is the conversion of wind energy into a useful form of energy, such as using wind turbines to make electricity, wind mills for mechanical power, wind pumps for pumping water or drainage, or sails to propel ships.
Geothermal 0.2% — is power extracted from heat stored in the earth. This geothermal energy originates from the original formation of the planet, from radioactive decay of minerals, and from solar energy absorbed at the surface.
Biofuels 0.2% — the primary biofuels are bioethanol and biodiesel. Bioethanol is an alcohol made by fermenting the sugar components of plant materials and it is made mostly from sugar and starch crops. Biodiesel is made from vegetable oils, animal fats or recycled greases.
Solar Photovoltaic (PV) 0.02% — are arrays of cells containing a material that converts solar radiation into direct current electricity.