Energy for the Present and Future: A World Energy Overview

For many years coal and oil have been used as energy sources. Currently oil is the dominant source of energy, but experts predict that in a few decades it will no longer be profitable. Burning fossil fuels generates atmospheric contaminants that give rise to the greenhouse effect that artificially warms the earth, damages the earth ozone layer, and produces acid rain, all of which are very dangerous for living beings. As a consequence, abnormal phenomena such as the melting of glaciers, changes in the Gulf Stream, unprecedented heat waves, floods, hurricanes, and damage to marine organisms are now occurring. Although there are many skeptics, there is a general consensus that the earth is warming up. In order to reduce CO

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and other greenhouse gas emissions, the extensive use of alternative and cleaner sources of energy have been proposed, including CO

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emission-free nuclear energy and other alternative sources, among which are hydraulic, hydrogen, solar, eolic, biomass and geothermal. Another future alternative is to use methane hydrates, which have clean combustion and are believed to have considerable, still-unexplored reserves. It is also important to implement measures to improve energy efficiency for reducing greenhouse gas emissions. In this paper we review present and future energy sources, including both primary non-renewable and alternative sources of energy. There is still time to take corrective measures by replacing some polluting fuels with clean sources of energy that can contribute to inherit a clean and sustainable world for future generations.