Monday, July 22, 2013

The Pros and Cons of Wind Power (repost)

I wrote this piece during my internship at the Society for Range Management for the SRM Outreach Blog. It's about the positive and negative aspects of wind power based on an article I read. I thought it would be appropriate for Monday since I usually write about some environmental topic or other on Mondays... Anyway enjoy! :)

CQ Researcher is a periodical that covers some of the most debated social and political topics of today. I recently read a CQ Researcher article titled, “Wind Power: Is Wind Energy Good for the Environment?” written by David Hosansky, which I found to be especially informative.  
Photo by Maggie Haseman,
 National Renewable Energy Laboratory in Golden, CO
In his article Hosansky outlines the history of how humans have harnessed the power of wind. Between 5,500 B.C.E. and 1,400 A.C.E., wind power was first employed in Southeast Asia to sail boats, and in windmills to pump water and grind grain. In the 18th and early 19th century and during the Industrial Revolution, steam began to replace wind, a well established energy source throughout Europe, as a power source. By the late 19th century, however wind reclaimed its early importance when scientists began developing windmills to bring electricity to rural areas, especially in Scotland, the United States, and Denmark. In the 1900s to 1980s most of the U.S. was reliant on nuclear energy and fossil fuels for electricity, farmers however used small windmills for irrigation pump operation. Between 1990 and present day, interest in alternative energy has increased due to rising oil prices, among other factors. Today, Hosansky cites China as the wind power world leader with a wind-energy capacity of 42 gigawatts, followed closely by the U.S. at 40 gigawatts.

A wind turbine works by capturing energy when the wind blows past the blade, there is a “lift” effect causing the blades to turn. As the blades turn, a shaft that is connected to the generator spins, creating electricity.

Wind Turbine Diagram and Parts

Blades: Every turbine usually has either two or three blades.
Rotor: The blades and the hub together are called the rotor.
Pitch: Blades are turned, or pitched, out of the wind to control the rotor speed.
Brake: A disc brake, which can stop the rotor in emergencies.
Low-speed shaft: The rotor turns the low-speed shaft at about 30 to 60 rotations per minute.
Gear box: Gears connect the low-speed shaft to the high-speed shaft and increase speeds from about 30 to 60 rotations per minute (rpm) to 1,000 to 1,800, rpm, the speed required by most generators to produce electricity.
Generator: Produces 60-cycle AC electricity.
Controller: The controller starts up the machine at wind speeds of about 8 to 16 miles per hour (mph) and shuts off the machine at about 55 mph.
Anemometer: Measures the wind speed and transmits wind speed data to the controller.
Wind vane: Measures wind direction and communicates with the yaw drive to orient the turbine properly with respect to the wind.
Nacelle: Contains the gear box, low- and high-speed shafts, generator, controller, and brake.
High-speed shaft: Drives the generator.
Yaw drive: Keeps the rotor on upwind turbines facing into the wind as the wind direction changes.
Yaw motor: Powers the yaw drive.
Tower: Towers are made from tubular steel, concrete, or steel lattice.
Caption Source:  Department of Energy
Photo Source: Turbine Zone

Some of the issues I found interesting in Hosansky’s paper include the problem of wind intermittency, the financial constraints involved with wind power, the effect wind energy can have by displacing some emissions and pollutants, concerns about wildlife protection, and the land requirements for a wind farm.

Photo by Charles Haseman,
Along I-80 near Des Moines, Iowa
 Living in Colorado, a relatively windy state, I don’t notice a lack of wind but this article reminded me that not every place in the U.S. or the world receives gusts as powerful as those throughout the Great Plains and the west coast. The article discusses that wind power seems to be a perfect fit for the U.S., according to Hosansky, If wind turbines had the ability to operate at 100% of their capacity, wind power has the potential to supply 16 times the electricity needs of the United States; however wind turbines only generate 25-40% of their capacity due to wind intermittency. Another challenge is that the locations with the most persistent wind tend to be in sparsely populated areas away from major population centers and not necessarily when the demand for energy peaks.  As a result, a large network of transmission lines is necessary to deliver the wind energy to the consumers, which could be costly.

I find the financial controversy outlined by Hosansky particularly fascinating. In order to reach the current U.S. goal of generating 20% of energy by wind power, the estimated cost is $200 billion, likely to be burdened onto ratepayers. This money would be used for turbines, improved transmission line capability and other infrastructure. Wind farms can also lower property value by up to 40%. On the other hand, turbines can result in local governments receiving “higher real estate tax revenue” and landowners leasing their land to build towers for $3,000 to $5,000 a year. The renewable energy standard President Obama presented will protect consumers from unstable fuel prices, save money, boost the economy and create green jobs. In addition the price of wind power is less than other renewable-energy sources.

Photo by Charles Haseman,
Along I-80 near Des Moines, Iowa
To me, Hosansky’s summary of the effect of carbon dioxide and other pollutants, which are often noted as the culprits for climate change, and the way wind power impacts them is enlightening. “The extraction, transport and combustion of… fossil fuels can affect water and air quality, wildlife habitats and the global climate.” Additionally green energy does not necessarily include all renewable energies; cycling fossil fuel plants up and down in response to the intermittent wind is expensive and “can emit excessive pollution” and reduce the “effectiveness of environmental-control equipment.” In order to reduce emissions it would be more efficient to directly address that problem. Conversely, wind energy is a key energy source to reducing air pollution and carbon dioxide and other emissions from coal and natural gas. Besides hydropower, wind energy generates the most amount of electricity compared to every other renewable energy sources, and it is considered safer than nuclear energy. A combination of diverse mixed fuel sources such as wind, solar and a back-up system of newer and more efficient gas-fired plants that can be quickly ramped up or down can reduce emissions significantly because fossil fuel plants won’t be running as often.

Photo by Charles Haseman,
Along I-80 near Des Moines, Iowa
Possibly the most popular argument against wind power that I have heard is about the detrimental effects it can have on wildlife, particularly birds and bats; Hosansky explains this captivating argument. Thousands of birds, including rare raptors such as golden eagles and burrowing owls have been killed by the blades of wind mills, and others have been electrocuted by wind-farm power lines. Additionally, in one year 2,000 bats may have been killed by a single wind farm. However, others suggest that wind farms can be placed far from migratory paths and “major populations of birds and bats” where such effects are less likely. Experts say that many reports of wildlife death were made prior to technological advances; modern wind mills are taller and kill far fewer animals. One report stated that turbines are low on the list of reasons why birds and bats die; pesticides, attacks by domestic and feral cats and collisions with windows kill much greater number of birds.

Photo by Maggie Haseman,
 National Renewable Energy Laboratory in Golden, CO
Another interesting argument discussed by Hosansky concerns land requirements. “Wind farms require far more land… than traditional forms of electricity generation”; estimates say “45 times more than nuclear power and several times more than coal and natural gas plants”. Furthermore, the location of wind farms can damage sensitive ecosystems and destroy beautiful landscapes. Alternatively, ”the turbines take up relatively little space and [the] land around” them can still be utilized for other purposes such as farming, ranching and recreation, thus taking up less space than fossil fuel plants overall. Additionally, improvements in technology continue to allow for larger turbines, meaning fewer are necessary to generate the same amount of electricity. Moreover, between smog and a windmill, one person stated they’d take the windmill.

This article was eye-opening to me and really gave some insight into benefits of and current issues with wind power. I now believe I have formed an educated opinion around wind energy and based on the issues discussed above I personally support wind power. It seems that the issues with it can be solved and, in my opinion, the issues, when they are compared to the benefits, are minor. I enjoyed reading the story-like writing and the political perspective on wind energy. If you would like to read this article too, here is the citation:

Hosansky, D. (2011, April 1). Wind Power: Is wind power good for the environment?. CQ Researcher, 21, 289-312.