Grand Coulee Dam. Picture 11.2. Top hydropower producting states 2007 39 It is important to note that only a small percentage of all dams in the United States produce electricity. Most dams were constructed solely to provide irrigation and flood control. 11.3 Hydropower and the environment Some people regard hydropower as the ideal fuel for electricity generation because, unlike the nonrenewable fuels used to generate electricity, it is almost free, there are no waste products, and hydropower does not pollute the water or the air. However, it is criticized because it does change the environment by affecting natural habitats. For instance, in the Columbia River, salmon must swim upstream to their spawning grounds to reproduce, but the series of dams gets in their way. Different approaches to fixing this problem have been
Renewable energy is energy generated from natural resources such as sunlight, wind, rain, tides, and geothermal heat, which are renewable. Renewable energy uses natural resources that can be replaced or "renewed" without harming the environment and does not contribute to the greenhouse effect and global warming. Non-renewable energy Non-renewable energy comes from sources that can't be replenished in a short period of time. We get most of our energy from nonrenewable energy sources, which include fossil fuels such as oil, natural gas, coal and from nuclear energy. Unfortunately, burning fossil fuels produces greenhouse gases like carbon dioxide and methane which may cause global warming. Wind energy is the world's fastest growing energy technology. Most renewable energy comes either directly or indirectly from the sun. Hydroelectric energy is the oldest and largest source of renewable energy.
out and compressed into squares called "briquettes." Biomass can also be converted into biofuel. A major advantage of biomass is that it can be stored and used when it is needed. Negative aspects of biomass energy Growing crops for biofuels requires large amounts of land and pesticides. Some pesticides could pollute the air and water. Biomass energy can also be a non renewable energy source. If people do not replant biomass feedstocks as fast as they use them, biomass energy becomes a nonrenewable energy source. Conclusion Renewable energy is generated from natural resources. Renewable energy sources are sunlight, wind, geothermal heat, water and various forms of biomass. These renewable sources cannot be exhausted and they are constantly renewed. They do not harm the environment. Using renewable energy you can save your money and protect the environment. References http://worldnuclear.org/info/EnergyandEnvironment/RenewableEnergyandEle http://environment.nationalgeographic
annaabi.ee 
Sisene Facebook'ga
Sisene Google'ga
Sisene LinkedIn'ga
