The concept of energy as we now understand it—a conserved quantity that represents the ability to do work—has been with us for less than two centuries. Yet its central role...
Focus: Impacts of Humans and Their Economy on the EnvironmentLast Updated on 2009-02-27 21:45:49The National Science Foundation (NSF) has issued a Dear Colleague Letter to the scientific community ". . . encouraging increased research . . . on the links among environment, society and the economy."
Image Above: NSF is supporting research on climate change and Earth's environment, society and economy. Credit: Department of Sustainability and Environment, State of Victoria, Australia More »
Ten most distortionary energy subsidiesLast Updated on 2008-09-17 09:51:46
Spiraling energy demand and rising environmental costs are growing concerns around the world. Governmental responses all too often involve issuing a torrent of energy plans, white-papers, and legislation. In an ideal world, government policies should work in tandem with market forces to achieve an adequate energy supply mix that is cleaner and more diverse than what preceded it. These synergies do not currently exist. In fact, there are thousands of government policies in place around the world that act counter to stated objectives with regard to energy security, diversification, and environmental protection.
The ten distortionary energy subsidies discussed below represent policies that, if corrected, would materially realign price signals to more effectively achieve energy market end goals. The list was generated with input from a variety of subsidy analysts around the world on... More »
Waste-to-energyLast Updated on 2008-09-17 09:50:05
Municipal Waste Combustor
Waste-to-energy is the process in which waste is used to generate useful energy –electricity, heat or both. This is possible (and convenient) when the heat generated by burning the waste is high enough to warrant satisfactory combustion conditions and make available enough energy to overcome losses and auxiliary consumption: in practice, a lower heating value of at least 4 megajoules per kilogram. Waste-to-energy is the offspring of waste incineration, which was originally introduced to sterilize and reduce the volume of waste by combusting it in a furnace. Modern waste-to-energy plants allow the export of energy, with very low environmental impact. The plant comprises four basic sections: waste combustor, recovery boiler, flue gas treatment and steam cycle. The design of the combustor varies widely with the waste characteristics: physical state... More »
Wind farmLast Updated on 2008-09-17 09:47:28A wind farm (often also called a wind park) is as a cluster of wind turbines that acts and is connected to the power system as a single electricity producing power station.
A wind farm. (Source: National Renewable Energy Laboratory)
Generally it is expected that a wind farm consists of more than three wind turbines. Modern wind farms may have capacities in the order of hundreds of megawatts, and are installed offshore as well as on land. Modern wind farms generally are connected to the high voltage transmission system, in contrast to the early application of wind energy for electricity production with wind turbines individually connected to the low- to medium-voltage distribution system. Hence, modern wind farms are considered power plants with responsibilities for control, stability, and power balance. Thus, wind farms are required to contribute to the control of voltage,... More »
Strip miningLast Updated on 2008-09-17 09:44:23
A coal strip mining operation. Photo: USGS
Strip mining is a type of surface mining that involves excavating earth, rock, and other material to uncover a tabular, lens-shaped, or layered mineral reserve. The mineral extracted is usually coal or other rocks of sedimentary origin. The mineral reserve is extracted after the overlying material, called overburden is removed. The excavation of the overburden is completed in rectangular blocks in plain view called pits or strips. The pits are parallel and adjacent to each other with each strip of overburden and the mineral beneath extracted sequentially. The mining process using equipment and explosives move the overburden laterally to the adjacent empty pit where the mineral has been extracted. This lateral movement is called casting or open-casting. The overburden is moved by explosives, draglines, bucketwheel excavators, stripping... More »
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