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The term "alternative" presupposes a set of undesirable energy technologies against which "alternative energies" are contrasted. As such, the list of energy technologies excluded is an indicator of which problems the alternative technologies are intended to address. Controversies regarding dominant sources of energy and their alternatives have a long history. The nature of what was regarded alternative energy sources has changed considerably over time, and today, because of the variety of energy choices and differing goals of their advocates, defining some energy types as "alternative" is highly controversial.
In a general sense in contemporary society, alternative energy is that which is produced without the undesirable consequences of the burning of fossil fuels, such as high carbon dioxide emissions, which is considered to be the major contributing factor of global warming according to the Intergovernmental Panel on Climate Change. Sometimes, this less comprehensive meaning of "alternative energy" excludes nuclear energy (e.g. as defined in the Michigan Next Energy Authority Act of 2002).[2]
Historians of economies have studied the key transitions to alternative energies and regard the transitions as pivotal in bringing about significant economic change.[9][10][11] Prior to the shift to an alternative energy, supplies of the dominant energy type became erratic, accompanied by rapid increases in energy prices.
[edit]Coal as an alternative to wood
Historian Norman F. Cantor describes how in the late medieval period, coal was the new alternative fuel to save the society from overuse of the dominant fuel, wood:
"Europeans had lived in the midst of vast forests throughout the earlier medieval centuries. After 1250 they became so skilled at deforestation that by 1500 AD they were running short of wood for heating and cooking... By 1500 Europe was on the edge of a fuel and nutritional disaster, [from] which it was saved in the sixteenth century only by the burning of soft coal and the cultivation of potatoes and maize. "[12]
[edit]Petroleum as an alternative to whale oil
Whale oil was the dominant form of lubrication and fuel for lamps in the early 19th century, but the depletion of the whale stocks by mid century caused whale oil prices to skyrocket setting the stage for the adoption of petroleum which was first commercialized in Pennsylvania in 1859.[13]
[edit]Alcohol as an alternative to fossil fuels
Main article: Ethanol fuel
In 1917, Alexander Graham Bell advocated ethanol from corn, wheat and other foodstuffs as an alternative to coal and oil, stating that the world was in measurable distance of depleting these fuels. For Bell, the problem requiring an alternative was lack of renewability of orthodox energy sources.[14] Since the 1970s, Brazil has had an ethanol fuel program which has allowed the country to become the world's second largest producer of ethanol (after the United States) and the world's largest exporter.[15] Brazil’s ethanol fuel program uses modern equipment and cheap sugar cane as feedstock, and the residual cane-waste (bagasse) is used to process heat and power.[16] There are no longer light vehicles in Brazil running on pure gasoline. By the end of 2008 there were 35,000 filling stations throughout Brazil with at least one ethanol pump.[17]
Cellulosic ethanol can be produced from a diverse array of feedstocks, and involves the use of the whole crop. This new approach should increase yields and reduce the carbon footprint because the amount of energy-intensive fertilizers and fungicides will remain the same, for a higher output of usable material.[18][19] As of 2008, there are nine commercial cellulosic ethanol plants which are either operating, or under construction, in the United States.[20]
Second-generation biofuels technologies are able to manufacture biofuels from inedible biomass and could hence prevent conversion of food into fuel." [21] As of July 2010, there is one commercial second-generation (2G) ethanol plant Inbicon Biomass Refinery, which is operating in Denmark.[22]
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Renewable energy helps because we can reuse the energy for something else and doesn't pollute the atmosphere the gas we use has smoke that goes up to the atmosphere and that is what also causes Global Warming.
Renewable energy Kent
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