The Earth (Sol 3) is the 3rd planet circling a large star called the Sun (Sol) at the centre of our planetary system (the “Solar system”) not unlike the way planetary systems circle a galaxy of individual stars in the expanse of space we call the Universe.
We learn in elementary school that the source of natural “light” renewed each day as our planet revolves is in fact the only source of all life for its inhabitants food chain, but moreover it is the primary source for the entire closed living system of our planet – “all energy on earth comes from the Sun”.
Sunlight is the source of most renewable energy power, either directly or indirectly. The sun can be harnessed to produce solar energy — electricity for heating, cooling, and lighting homes, offices, entertainment complexes, airports, and a variety of other industrial structures.
Heat from the sun also produces wind, whose energy is captured by wind turbines and turned into electricity capable of powering entire towns.
Hydroelectric power is a function of “the water cycle” (a byproduct of sun light) which produces streams, rivers, and waterfalls (following precipitation – water descends from the atmoshpere to the earth) that flow downhill (to the ocean from which the same water ascends through the action of the Sun), their tremendous power turning large turbines that convert the flow to electricity. Industrialised nations have already developed most of the world’s large hydroelectric resources, but small-scale technologies are being developed that will provide additional localized power in the future.
Organic plant matter, known as biomass, can be burned, gasified, fermented, or otherwise processed to produce electricity, heat and biofuels for transportation. Bioenergy is another term for energy that is produced from biomass for any of these purposes.
Geothermal energy taps the Earth’s internal heat (renewable energy of it’s mantle & core generated by the natural breakdown of radioactive materials like uranium and thorium) in the form of steam for a variety of uses, including electric power production, and the heating and cooling of buildings. Some new systems are in development for harvesting even more power by injecting water back into underground heat sources to produce more steam.
Ocean energy can also be used to produce electricity. In addition to tidal energy, energy can be produced by the action of ocean waves, which are driven by both the tides and the winds. Because of their link to winds and surface heating processes, ocean currents are considered as indirect sources of solar energy.
Source: Council on Renewable Energy edited by Chris Burrell.