school energy&environment

Energy: yesterday and today

The history of mankind has always been characterized by the search for new sources of energy: to ensure survival at first and then to improve the standard of living. At the beginning energy meant manpower, often supplied by slaves and beasts of burden; later the energy of wind (windmills) and water (water mill wheels and similar machines) started to be exploited. Towards the end of the 19th century, thanks to the development of the industrial civilization, the need for energy was met thanks to the intensive use of coal. From the technological viewpoint a big step forward was made with the realization that heat, through the production of steam, could be transformed into mechanic energy. The first implementation of this new source of energy was the steam engine invented by Watt, which replaced traditional horses with the more modern “horse-power”. During the first decades of the 20th century, after a promising start of the hydroelectric energy, great oil field were discovered in the Middle East: the “black gold” rush had started. During the 1960s, after half a century of unmatched domination by oil, natural gas proved to be a valid alternative, especially as regards domestic use (cooking and heating) thank to its smaller environmental impact. At the beginning of the 1970s some countries started to develop nuclear energy, mainly to produce electricity. The development of nuclear energy, just like other alternative energy sources, can be explained by means of the marked increase in the oil prices caused by the “oil crises” which took place in 1974 and 1979 following the corresponding embargoes against the Arab oil exporting countries and, in 1990, during the Gulf war. The range of currently available energy sources includes oil, natural gas, coal, hydroelectric energy and nuclear energy according to a variable percentage distribution depending on the country. Other sources can be added to the main sources. Although their quantity is still limited, they are renewable: geothermal energy, solar energy, wind power, the energy obtained from waste or from biomass. The International Energy Agency (one of the main research institutes dealing with energy) expects that until 2020 the world energy consumption will increase by approximately 65% as compared to the current level. What sources will supply all the necessary energy to mankind? The availability of fossil fuels will be increasingly reduced over the years (owing to the depletion of resources) and to meet the growing demand for energy new sources will need to be exploited, especially renewable sources with a smaller environmental impact. One of the possible alternatives to oil is hydrogen. Hydrogen is an element contained in many substances, (from water to natural gas) and widely available on Earth. Hydrogen can be used in fuel cells: a device capable of activating a chemical-electric process transforming the energy contained in hydrogen into electricity and heat avoiding combustion, which is the cause of numerous polluting emissions in the air. The implementation of fuel cells will become possible in many sectors: transports (buses and cars), households (hot water production, heating and air conditioning) and electronics (mobile phones and computers). Currently available technologies for the production, preservation and use of hydrogen must be further tested and improved before this resource can be used on a wide scale.