Nonrenewable Resources!
Nuclear power, or nuclear energy, is the use of exothermic nuclear processes,[1] to generate useful heat and electricity. The term includes nuclear fission, nuclear decay and nuclear fusion. Presently the nuclear fission of elements in the actinide series of the periodic table produce the vast majority of nuclear energy in the direct service of humankind, with nuclear decay processes, primarily in the form ofgeothermal energy, and radioisotope thermoelectric generators, in niche uses making up the rest. Nuclear (fission) power stations, excluding the contribution from naval nuclear fission reactors, provided about 5.7% of the world's energy and 13% of the world's electricity in 2012.[2] In 2013, the IAEA report that there are 437 operational nuclear power reactors,[3] in 31 countries,[4] although not every reactor is producing electricity.[5] In addition, there are approximately 140 naval vessels using nuclear propulsion in operation, powered by some 180 reactors.[6][7][8] As of 2013, attaining a net energy gain from sustained nuclear fusion reactions, excluding natural fusion power sources such as the Sun, remains an ongoing area of international physics and engineering research. More than 60 years after the first attempts, commercial fusion power production remains unlikely before 2050.[9]
There is an ongoing debate about nuclear power.[10][11][12] Proponents, such as the World Nuclear Association, the IAEA andEnvironmentalists for Nuclear Energy contend that nuclear power is a safe, sustainable energy source that reduces carbon emissions.[13]Opponents, such as Greenpeace International and NIRS, contend that nuclear power poses many threats to people and the environment.[14][15][16]
Nuclear power plant accidents include the Chernobyl disaster (1986), Fukushima Daiichi nuclear disaster (2011), and the Three Mile Island accident (1979).[17] There have also been some nuclear submarine accidents.[17][18][19] In terms of lives lost per unit of energy generated, analysis has determined that nuclear power has caused less fatalities per unit of energy generated than the other major sources of energy generation. Energy production from coal, petroleum, natural gas and hydropower has caused a greater number of fatalities per unit of energy generated due to air pollution and energy accident effects.[20][21][22][23][24] However, the economic costs of nuclear power accidents is high, and meltdowns can render areas uninhabitable for very long periods. The human costs of evacuations of affected populations and lost livelihoods is also significant.[25][26]
Along with other sustainable energy sources, nuclear power is a low carbon power generation method of producing electricity, with an analysis of the literature on its total life cycle emission intensity finding that it is similar to other renewable sources in a comparison ofgreenhouse gas(GHG) emissions per unit of energy generated.[27] With this translating into, from the beginning of nuclear power stationcommercialization in the 1970s, having prevented the emission of approximately 64 gigatonnes of carbon dioxide equivalent(GtCO2-eq)greenhouse gases, gases that would have otherwise resulted from the burning of fossil fuels in thermal power stations.[28]
As of 2012, according to the IAEA, worldwide there were 68 civil nuclear power reactors under construction in 15 countries,[3] approximately 28 of which in the Peoples Republic of China (PRC), with the most recent nuclear power reactor, as of May 2013, to be connected to theelectrical grid, occurring on February 17, 2013 in Hongyanhe Nuclear Power Plant in the PRC.[29] In the USA, two new Generation III reactors are under construction at Vogtle. U.S. nuclear industry officials expect five new reactors to enter service by 2020, all at existing plants.[30] In 2013, four aging, uncompetitive, reactors were permanently closed.[31][32]
Japan's 2011 Fukushima Daiichi nuclear disaster, which occurred in a reactor design from the 1960s, prompted a re-examination of nuclear safety and nuclear energy policy in many countries.[33] Germany decided to close all its reactors by 2022, and Italy has banned nuclear power.[33] Following Fukushima, in 2011 the International Energy Agency halved its estimate of additional nuclear generating capacity to be built by 2035.[34][35]
COAL (from the Old English term col, which has meant "mineral of fossilized carbon" since the 13th century)[1] is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature andpressure. Coal is composed primarily of carbon along with variable quantities of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen.[2]
Throughout history, coal has been used as an energy resource, primarily burned for the production of electricity and/or heat, and is also used for industrial purposes, such as refining metals. A fossil fuel, coal forms when dead plant matter is converted into peat, which in turn is converted into lignite, then sub-bituminous coal, after that bituminous coal, and lastly anthracite. This involves biological and geological processes that take place over a long period. The Energy Information Administration estimates coalreserves at 948×109 short tons (860 Gt).[3] One estimate for resources is 18 000 Gt.[4]
Coal is the largest source of energy for the generation of electricity worldwide, as well as one of the largest worldwide anthropogenicsources of carbon dioxide releases. In 1999, world gross carbon dioxide emissions from coal usage were 8,666 million tonnes of carbon dioxide.[5] In 2011, world gross emissions from coal usage were 14,416 million tonnes.[6] Coal-fired electric power generation emits around 2,000 pounds of carbon dioxide for every megawatt-hour generated, which is almost double the approximately 1100 pounds of carbon dioxide released by a natural gas-fired electric plant per megawatt-hour generated. Because of this higher carbon efficiency of natural gas generation, as the market in the United States has changed to reduce coal and increase natural gas generation, carbon dioxide emissions have fallen. Those measured in the first quarter of 2012 were the lowest of any recorded for the first quarter of any year since 1992.[7] In 2013, the head of the UN climate agency advised that most of the world's coal reserves should be left in the ground to avoid catastrophic global warming.[8]
Coal is extracted from the ground by coal mining, either underground by shaft mining, or at ground level by open pit miningextraction. Since 1983 the world top coal producer has been China.[9] In 2011 China produced 3,520 million tonnes of coal – 49.5% of 7,695 million tonnes world coal production. In 2011 other large producers were United States (993 million tonnes), India (589),European Union (576) and Australia (416).[9] In 2010 the largest exporters were Australia with 328 million tonnes (27.1% of world coal export) and Indonesia with 316 million tonnes (26.1%),[10] while the largest importers were Japan with 207 million tonnes (17.5% of world coal import), China with 195 million tonnes (16.6%) and South Korea with 126 million tonnes (10.7%).[11]