Hydroelectric energy has several drawbacks that make it a less than ideal option compared to the clean power potential of solar energy. The factors are both aesthetic and environmental.
The most visible environmental aspect of Hydroelectricity is its impact on the environment, as it requires the damming of rivers. This causes the flooding of low lying land behind the dam and while this is often not desirable, the reality is that it is just an alteration to the environment. If the dam was to remain filled with water all the time, this would have no environmental effect outside the dam area.
What does cause problems, however, is the significant amount of methane generated by hydroelectric energy installations. Methane is produced when organic matter breaks down anaerobically (without oxygen). This is similar to the processes that resulted in the formation of coal, oil and natural gas.
The following gives you an idea of what happens to the land behind the dam after the Hydro facility has been built.
First the land is submerged and the vegetation with it. The vegetation drowns and begins to rot. Since there is very little available oxygen, the plant material breaks down to form, among other things, methane that is absorbed by the water.
Nothing unusual has occurred so far. This is exactly what would happen with any permanent flooding. But this is a power station and in most cases also an urban water supply. Because of this, the water levels will rise and fall greatly throughout the year, generally dropping to low levels in hot and dry seasons. During these times lower sides and possibly the bottom of the dam become exposed.
This exposed land is ideal for growing plants and so it blooms with new life. As most dams are shallow, the amount of land exposed at the edges as the water drops can be very large. The shallower the dam, the more land is exposed annually.
After a time the rains return and the dam fills up again. The new vegetation is then also covered with water and so rots anaerobically and so more methane enters the water of the dam.
This continues year after year, resulting in a slow but steady increase in the amount of methane absorbed in the water of the dam. This is a problem because methane is not very soluble in water. When the water passes through the dam's turbines it escapes the water and enters the atmosphere.
As a greenhouse gas, methane is approximately 21 times more potent than Carbon Dioxide. This means that electricity from a Hydro plant can be up to three times more polluting than from a coal or oil fired power station. This is of course dependent on the climate and geography of the dam's location. The effect is significant enough for the Intergovernmental Panel on Climate Change (IPCC) taking methane emissions into account when inventorying a nation's pollution totals.
Yes Hydroelectricity is a renewable energy source but it should not be seen as clean. Attaching electricity generators to urban water supply dams is logical, but other than that it would be far more sensible to use cleaner renewables such as wind and solar for electricity production. These power sources have no emissions at all associated with them once they have been constructed.
The most visible environmental aspect of Hydroelectricity is its impact on the environment, as it requires the damming of rivers. This causes the flooding of low lying land behind the dam and while this is often not desirable, the reality is that it is just an alteration to the environment. If the dam was to remain filled with water all the time, this would have no environmental effect outside the dam area.
What does cause problems, however, is the significant amount of methane generated by hydroelectric energy installations. Methane is produced when organic matter breaks down anaerobically (without oxygen). This is similar to the processes that resulted in the formation of coal, oil and natural gas.
The following gives you an idea of what happens to the land behind the dam after the Hydro facility has been built.
First the land is submerged and the vegetation with it. The vegetation drowns and begins to rot. Since there is very little available oxygen, the plant material breaks down to form, among other things, methane that is absorbed by the water.
Nothing unusual has occurred so far. This is exactly what would happen with any permanent flooding. But this is a power station and in most cases also an urban water supply. Because of this, the water levels will rise and fall greatly throughout the year, generally dropping to low levels in hot and dry seasons. During these times lower sides and possibly the bottom of the dam become exposed.
This exposed land is ideal for growing plants and so it blooms with new life. As most dams are shallow, the amount of land exposed at the edges as the water drops can be very large. The shallower the dam, the more land is exposed annually.
After a time the rains return and the dam fills up again. The new vegetation is then also covered with water and so rots anaerobically and so more methane enters the water of the dam.
This continues year after year, resulting in a slow but steady increase in the amount of methane absorbed in the water of the dam. This is a problem because methane is not very soluble in water. When the water passes through the dam's turbines it escapes the water and enters the atmosphere.
As a greenhouse gas, methane is approximately 21 times more potent than Carbon Dioxide. This means that electricity from a Hydro plant can be up to three times more polluting than from a coal or oil fired power station. This is of course dependent on the climate and geography of the dam's location. The effect is significant enough for the Intergovernmental Panel on Climate Change (IPCC) taking methane emissions into account when inventorying a nation's pollution totals.
Yes Hydroelectricity is a renewable energy source but it should not be seen as clean. Attaching electricity generators to urban water supply dams is logical, but other than that it would be far more sensible to use cleaner renewables such as wind and solar for electricity production. These power sources have no emissions at all associated with them once they have been constructed.
About the Author:
For more information on electricity generation and its issues, visit the Fossil Fuels section of Roger Vanderlely's website. There you can also find out about getting a good deal on cheap solar panels to become more energy independent and do your bit for the environment.
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