Human history can be told in terms of the history of energy. The discovery of fire, the domestication of animals, the discovery of fossil fuels, the electrification of cities, the oil wars in the Middle East, and advances in nuclear physics are all pivotal points in human history. Energy is a multifaceted concept; it is central to science and education, it plays pivotal role in economic growth, and it has a dominant position in international affairs. Conventional energy sources are major sources of environmental stress at global as well as local levels. Emissions from fossil fuels drive a range of global and regional environmental changes, including global climate change, acid deposition and urban smog. Coal mining disturbs vast areas of natural habitat, hydropower development can have significant environmental and social costs, and the exploration for and extraction of oil and natural gas can have significant impacts, particularly in sensitive ecosystems
A greenhouse gas is one of several gases that can absorb and emit longwave (infrared) radiation in a planetary atmosphere. This phenomenon is often termed the greenhouse...
Health effects of light pollutionLast Updated on 2016-02-23 11:04:42This article, written by Ron Chepesiun  appeared first in Environmental Health Perspectives—the peer-reviewed, open access journal of the National Institute of Environmental Health Sciences.
The article is a verbatim version of the original and is not available for edits or additions by Encyclopedia of Earth editors or authors. Companion articles on the same topic that are editable may exist within the Encyclopedia of Earth.
In 1879, Thomas Edison's incandescent light bulbs first illuminated a New York street, and the modern era of electric lighting began. Since then, the world has become awash in electric light. Powerful lamps light up streets, yards, parking lots, and billboards. Sports facilities blaze with light that is visible for tens of miles. Business and office building windows glow throughout the night. According to the Tucson, Arizona–based... More »
Nuclear powerLast Updated on 2015-08-28 08:36:17Nuclear power is the generation of electricity from controlled reactions within the nucleii of atoms that release energy used to boil water, the steam from which drives a turbine to generate electricity . All commercial nuclear plants presently rely upon nuclear fission reactions.
As of 2010, approximately 14 percent of the world's electricity was derived from nuclear power, chiefly centered in the United States (with 31% of the world's total nuclear power capacity), France (16%), and Japan (10%).
The International Atomic Energy Agency (IAEA) reports that, as of November 21, 2012, there are 437 nuclear power reactors in operation in 30 countries, plus Taiwan. Another 64 reactors under construction in 14 countries which if operational today would increase the worldwide electrical generation capacity of nuclear power by 17%. One hundred and forty reactors have been permanently... More »
Deepwater Horizon Oil Spill: The Fate of the OilLast Updated on 2015-02-02 17:02:07Summary
The April 20, 2010, explosion of the Deepwater Horizon offshore drilling rig led to the largest oil spill in U.S. waters. Federal government officials estimated that the deepwater well ultimately released (over 84 days) over 200 million gallons (or 4.9 million barrels) of crude oil. Although decreasing amounts of oil were observed on the ocean surface following the well’s containment on July 15, 2010, oil spill response officials and researchers have found oil in other places. A pressing question that has been raised by many stakeholders is where did the oil go?
On August 4, 2010, the federal government released an estimate of the oil spill budget for the Deepwater Horizon incident. On November 23, 2010, the federal government released a peerreviewed “Technical Document” that further explained how the estimates were derived, and in some cases, modified the... More »
Energy profile of CanadaLast Updated on 2014-11-30 21:44:07 Canada is one of the world's five largest energy producers and is the principal source of U.S. energy imports.
Canada is a net exporter of most energy commodities and is an especially significant producer of conventional and unconventional oil, natural gas, and hydroelectricity. It stands out as the largest foreign supplier of energy to the United States, its southern neighbor and one of the world's largest consumers of energy. Just as the United States depends on Canada for much of its energy needs, so is Canada profoundly dependent on the United States as an export market. However, economic and political considerations are leading Canada to consider ways to diversify its trading partners, especially by expanding ties with emerging markets in Asia.
Canada's large territory is endowed with an exceptionally rich and varied set of natural resources, which enables it to... More »
Wind Energy and Wind TurbinesLast Updated on 2014-11-30 21:43:17Since 1999 the United States’ installed capacity of wind-produced electricity has grown from 2,000 mW to 28,635 mW, which is enough energy to power the equivalent of more than 6.5 million homes.
A functioning turbine can provide electricity directly to a building or other application as a “stand-alone,” or “off-grid” system, or it can be connected to the transmission grid. Hybrid systems can combine wind, solar, and, for example, a diesel or biogas electric generator to provide holistic energy security for off-grid systems.
A small wind turbine is one that generates 100 kilowatts (“kWs”) or less, and is generally used to produce clean, emissions-free power for individual homes, farms and businesses. As compared to large commercial turbines that may be 300 feet tall and are capable of producing several megawatts... More »
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