Environmental Consequences of Renewable Energy Sources

Dwindling supply and negative environmental impact is pushing the public to embrace renewable energy sources in exchange of conventional fossil fuels. When burned, coal and oil release tons of carbon dioxide, methane, and other greenhouse gasses into the atmosphere, with the potential to cause catastrophic impacts on the environment. The impending threat of global warming is pressing environmental scientists and engineers to improve the systems we use to gather renewable energy from unlimited natural resources. Each method of generating usable electricity has its own set of environmental problems, but people are always researching ways to improve them. Compared to the environmental consequences of burning fossil fuel to generate electricity, the pros of using renewable energy sources outweigh the cons.

Wind Power:

Wind is a natural phenomenon that has no foreseeable end. It is a source of unlimited energy, and the turbines used to generate usable power from wind are relatively safe for the environment and produce no greenhouse emissions. The main cons of wind power are the amount of space they use, and their potential impact on local bird populations. Improvements are constantly being applied and are based on the many studies and assessments done to examine the ways the turbines impact the environment around them.

While large amounts of land are required to have a productive wind farm, the space between turbines is not exclusively for the turbines only. The towers can be constructed on leased farmland, where they can sit amongst the crops and animals. Cattle and other farm animals are often seen grazing nearby, resting in their shade, or using them as a scratching post. Farmers can plant crops right up to the base and several studies have shown that crops like corn and soybeans benefit from the decreased frosts and fungus caused by the turbines’ presence. An unexpected benefit is that wind turbines are already combating global warming in their own way. Studies have shown that the turbulence generated by the turning of their blades can keep the surrounding temperatures from getting too hot in the day and too cold in the night. Studies imply that crops planted near the turbines are protected from damaging frost and fungi because of the impact they have on the surrounding temperature. The most extreme issue raised by the use of wind turbines is the impact they have on local bird populations. By doing a population count before construction, during construction, and after construction, scientists are able to gauge whether or not the wind farm produces a negative effect on local populations. There are cases in which rare and endangered bird species have died after flying into the spinning blades. Studies on the common causes of bird death place wind farms towards the bottom of the list, with the worst offenders being the Transmission lines of conventional fossil fuel power plants, hunters, and domestic cats. (graph in Wikipedia of bird casualties)

Hydropower:

Hydropower plants harness the natural energy of flowing water, and produce zero emissions. Any of the negative impact a dam causes on its environment is often magnified by the size of the dam.  New, large-scale dams are rare because the most suitable sites are usually under environmental protection. As a result, the demand for hydropower is failing. The development of new dams is further impacted by frequent protests from environmental activists who seek to preserve the natural flow of the river and the preservation of local fish populations. Fish counts confirm that the spinning blades of the generators can kill unwary fish, and not all fish will think to use the built in fish ladders many power plants install to please activists. Some power plants use flashing lights to direct the fish away from the turbines, but so far, the safest solution seems to be to shut them down during fish migrations. This solution is ineffective for the power plant, and the company looses money during this time. Fish aren’t the only animals that are affected by a hydropower dam. When a new dam is built, the flow may need to be redirected in order to maximize power generation, which can impact wildlife on land and their environment. The dam reserves water upstream, creating a man-made lake that floods the surrounding forest while downriver of the dam; the water level is liable to drop. Case studies of the current impact of established dams provide scientists with the information they need to improve the dams and reduce environmental consequences. 

Solar Energy:

Solar power cells are growing in popularity, especially in urban areas on roofs above the trees. The main con of solar energy is the hazardous materials used in production of the solar cells, and waste materials left behind, as well as the necessary space required for installation and the large price tag. Large-scale solar energy farms are very expensive, and they take up a lot of space, since they need to have the sun on them at all times. The space in between cells cannot be used for anything, since there isn’t much space left. Because they take up so much space, smaller cells meant for personal use have started appearing in cities and towns. Instead of filling fields, they are being places on the roofs of homes, airport hangers, and other places with space may have otherwise been left vacant. In addition to generating a lot of energy for personal use, a building that generates more energy then they can use are able to earn money by putting that power onto the grid. A problem with small-scale urban solar cells is that they are made of the same hazardous materials as the large-scale cells, and may produce toxic fumes during a fire. These fumes are dangerous for firefighters who may need to enter the building. Current research on experimental solar power aims to reduce hazardous materials and waste in production, as well as to improve the efficiency of the small-scale solar cells. One of the several improvements in progress is a solar concentrator, which is used to generate electricity, and when mounted on solar trackers, can adjust its position to optimize solar energy gathered. Another option being researched is space-based solar power designed to sit on satellites, and have the potential to gather ten times the amount of energy then they would on earth. By installing efficient solar panels in cities, it is possible to generate much of the power needed there daily, and severely reducing the need for coal and oil power plants. 

Sample Question:

What are the potential consequences of using Hydropower?

1. a. Fish will get caught in the blades of the turbines
2. b. The river upstream might flood the surrounding woods
3. c. Concerned local activists may protest
4. d. All of the above

By reading the passage on hydropower, you can judge what will happen when you build a hydropower dam. That way, you can eliminate any answer that doesn’t make sense, and pick the answer that you think is correct.

Why are scientists trying to improve the design of solar energy cells?

1. a. Because the sun is patchy, and it’s difficult to gather enough energy
2. b. Because solar energy cells may release toxic fumes during a house fire
3. c. Because the materials used during production are expensive and hazardous
4. d. Because the large energy farms are less efficient then small urban solar cells

Many of these answer might seem like the correct answer, in this case, you would need to look back at the passage and start eliminating answers. If you can’t judge which answer would be the right one, go with the answer that either feels the best, or that seems least wrong.

Sources:

http://www.ucsusa.org/clean_energy/technology_and_impacts/impacts/environmental-impacts-of.html 

http://en.wikipedia.org/wiki/Solar_power#Experimental_solar_power

http://en.wikipedia.org/wiki/Wind_farm#Environmental_and_aesthetic_impact

http://www.businessgreen.com/bg/news/2167515/report-wind-turbines-little-impact-bird-populations

http://en.wikipedia.org/wiki/Environmental_impact_of_wind_power#Impact_on_wildlife

http://www.hydroquebec.com/sustainable-development/documentation/etudes_impacts.html