Secondary 2-Edward Index 25

[* Project Scheme *]

============================== Project : Different Ways of Obtaining Energy. ==============================

[Group Project Members]

[Maris Stella High School] ===========================* Members : Secondary 2E ===========================* (25)Peh Seng Lee Daryl ----------- (Presenter, Researcher, Co-Leader & Coordinator) <<<<<<<<<<<<<<<<<<<<<<<<<<> <<<<<<<<<<<<<<<<<<<<<<<<<<> <<<<<<<<<<<<<<<<<<<<<<<<<<> (26)Quek Jun Hao Nicholas ------ (Researcher, Encourager) <<<<<<<<<<<<<<<<<<<<<<<<<<> <<<<<<<<<<<<<<<<<<<<<<<<<<> <<<<<<<<<<<<<<<<<<<<<<<<<<> (27)Reuben Wang Xianwei ------- (Leader, Researcher & Commenter) <<<<<<<<<<<<<<<<<<<<<<<<<<> <<<<<<<<<<<<<<<<<<<<<<<<<<> <<<<<<<<<<<<<<<<<<<<<<<<<<> (28)Russel Tan Tian Jie ----------- (Researcher, Organizer) <<<<<<<<<<<<<<<<<<<<<<<<<<> ===========================

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Tuesday, March 3, 2009

reflection week 8 & 9 by Russell

hi sorry for late post... my mac went for a 'holiday'. as i promised... i will be covering pros and cons of hydroelectricity

Advantages
Inexhaustible fuel source
Minimal environmental impact
Viable source--relatively useful levels of energy production
Can be used throughout the world
Economics
The major advantage of hydroelectricity is elimination of the cost of fuel. The cost of operating a hydroelectric plant is nearly immune to increases in the cost of fossil fuels such as oil, natural gas or coal, and no imports are needed.
Hydroelectric plants also tend to have longer economic lives than fuel-fired generation, with some plants now in service which were built 50 to 100 years ago. Operating labor cost is also usually low, as plants are automated and have few personnel on site during normal operation.
Where a dam serves multiple purposes, a hydroelectric plant may be added with relatively low construction cost, providing a useful revenue stream to offset the costs of dam operation. It has been calculated that the sale of electricity from the Three Gorges Dam will cover the construction costs after 5 to 8 years of full generation.

Greenhouse gas emissions
Since hydroelectric dams do not burn fossil fuels, they do not directly produce carbon dioxide (a greenhouse gas). While some carbon dioxide is produced during manufacture and construction of the project, this is a tiny fraction of the operating emissions of equivalent fossil-fuel electricity generation.

Disadvantages
• Smaller models depend on availability of fast flowing streams or rivers
• Run-of-the-River plants can impact the mobility of fish and other riverlife. NOTE: Building a fish ladder can lessen this negative aspect of hydroelectric power
Environmental damage
Hydroelectric projects can be disruptive to surrounding aquatic ecosystems both upstream and downstream of the plant site. For instance, studies have shown that dams along the Atlantic and Pacific coasts of North America have reduced salmon populations by preventing access to spawning grounds upstream, even though most dams in salmon habitat have fish ladders installed. Salmon spawn are also harmed on their migration to sea when they must pass through turbines. This has led to some areas transporting smolt downstream by barge during parts of the year. In some cases dams have been demolished (for example the Marmot Dam demolished in 2007) because of impact on fish. Turbine and power-plant designs that are easier on aquatic life are an active area of research. Mitigation measures such as fish ladders may be required at new projects or as a condition of re-licensing of existing projects.
Population relocation
Another disadvantage of hydroelectric dams is the need to relocate the people living where the reservoirs are planned. In February 2008, it was estimated that 40-80 million people worldwide had been physically displaced as a direct result of dam construction. In many cases, no amount of compensation can replace ancestral and cultural attachments to places that have spiritual value to the displaced population. Additionally, historically and culturally important sites can be flooded and lost. Such problems have arisen at the Three Gorges Dam project in China, the Clyde Dam in New Zealand and the Ilısu Dam in Southeastern Turkey.

logged on @ 4:37 AM
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