With the world becoming more and more interested in renewable energy sources, wind power too has gotten more and more attention as an extremely viable source for electricity generation. In fact, in 2013, Spain reported that wind farms produced more electricity than any other form of energy production, including coal and nuclear power stations. This shows just how important wind power is becoming on a world stage.
To harness the wind’s power, large wind turbines are erected. These can be as tall as a twenty story building with 200 ft. blades. To create electricity, the wind spins the blades of the turbine. This, in turn spins a shaft that is connected to an electrical generator. In order to maximize energy production, turbines are often clumped together, sometimes hundreds in a row in a wind farm. These farms attempt to place the turbines in windy spots, such as on ridges or off shore, and space them out in just the right way, again to maximize energy production.
Wind power is also growing in popularity because it is an extremely inexpensive form of energy. Wind is free, so, once the turbines are up and running there is very little cost to run these farms. Mass production of the wind turbines themselves has reduced the costs as well as government tax breaks and incentives designed to bolster the wind-energy industry.
Wind turbines also have a net energy gain, meaning that eventually, they produce more energy than was consumed during their construction. In fact, during a turbine’s lifetime, it produces several times more energy than was required to build it, making turbines both economically and energetically efficient. Furthermore, the energy return on investments, or the EROI is quite high. For wind turbines, this number (calculated by dividing the total energy generated by the energy required to build the turbine), ranges from 5 to 35 according to a meta study. This study examined data from 1997 to 2007. So, the lower EROI can be attributed to older, out of date technology. Now, the most common wind turbines have an EROI of 16. This is important because in developed countries, 7 is considered the minimum EROI.
So, wind turbines seem like the perfect system. They take free wind and turn it into electricity at a very low cost. But what are the effects of these structures on the surrounding environment? Is wind power too good to be true?
First, let’s consider the variability of wind itself. Wind turbines can only produce electricity if there is wind to move the blades. So, in order to prevent the entire system or the electrical grid from shutting down when the weather does not cooperate, many wind farms employ a buffering system. Meaning that in order to continue energy production, many farms switch energy generation reserves. These are systems that are able to adapt to accommodate changes in energy supply and demand. Ideally, these are powered by a reliable and clean energy source, such as hydroelectric energy (energy produced by the kinetic energy of flowing water). But, in the United States, most of these reserves are actually powered by natural gas. So in reality, wind power in the U.S. is not entirely renewable because it is a hybrid of wind and this natural gas. Therefore, the environmental impact is not as minor as it would appear. Yes, the wind power does offset some the CO2 emissions created by the natural gas power plant. In fact, scientists believe that on average, the addition of only 3 more MW of wind energy to the U.S. electric grid would decrease the emissions of CO2 from fossil power plants by 1,200 pounds per hour. But, even so, they are not replacing these emissions. Since wind is only available about 30% of the time, in reality, most of our “wind energy” actually comes from natural gas, a non renewable resource.
Again, it is possible to employ the buffering system without using fossil fuels. A great example of a country that makes it’s wind power work without using fossil fuels is Denmark, one of the most wind-energy-intensive countries world wide. Instead of buffering their wind energy against fossil fuels like the U.S., they partner with nearby Sweden and Norway and take advantage of their hydroelectric energy. So, when wind is blowing, Denmark exports electricity to Sweden, who can then store more water in their dams. Then, when the wind is not blowing, Sweden can release the stored water and export electricity back to Denmark. This symbiotic relationship is relatively eco-friendly because it uses all natural and renewable resources. However, it is only viable because of the unique geographic features and locations of the countries.
Another aspect to consider when examining environmental impact is harmful emissions which create air pollution. While in operation, wind turbines do not release C02 emissions, which is one reason why wind power is so popular.
However, one must examine the wind turbines from construction to dismantling, or the entire life cycle, in order to get a full picture of the environmental impact. According to the life cycle assessments of wind energy, turbines do contribute harmful emissions into the atmosphere, particularly during the construction phase. However, most of the emissions are nearly negligible, especially compared to more conventional methods using fossil fuels such as natural gas. Unfortunately, wind farms do emit more particulate matter per unit of energy created (kWh) than do fossil fuel plants. This particulate matter refers to any tiny liquid or solid that because of the wind turbines is suspended in Earth’s atmosphere such as natural or cement dust.
Furthermore, in 2006, a European study examined externality costs, or costs of external pollution. Externality is an economic term that refers to the cost to a person who didn’t choose to receive that cost. In our case, the externality cost would refer to the communities near these various power plants. This study found that for wind power, externality costs were 0.09 – 0.12c€/kW. This is an extremely low cost, especially compared the 1.6-5.8 c€/kWh externality costs of fossil fuels. To put these numbers into perspective, energy costs in Europe are approximately 10 c€/kWh. So, the externality costs of wind power are a tiny fraction of total energy costs, showing that wind power does not cause a significant amount of pollution.
One must also examine the impact on wildlife to form a full picture of the impact of wind power on the environment. Wind turbines pose a huge threat to flying creatures such as bats and birds. One study examined impact of wind turbines on bird deaths and estimated that wind turbines in the U.S. kill an average number of 234,000 birds annually. However, there are a plethora of causes for bird death in the United States. Compared to fossil fuel plants which are responsible for approximately 14 million bird deaths or even buildings and windows which are responsible for a shocking 365 – 988 million, wind turbines, again have very little relative impact on the lives of the birds. That being said, wind farm can implement mitigation factors, especially to help conserve at risk species. The Peñascal Wind Power Project in Texas has just such a practice in place. It’s wind farm is located directly along a major migration route for birds. So, the farm has implemented an avian radar to detect approaching birds. If the birds appear to be in danger of running into the blades, then the farm shuts down the turbines and allows the birds to pass. So, although wind farms can be harmful to birds, there are ways in which to minimize these harmful effects. In fact, the Royal Society for the Protection of Birds issued a statement saying that “climate change poses the single greatest long-term threat to birds and other wildlife” as well as saying that “the available evidence suggests that appropriately positioned wind farms do not pose a significant hazard for birds.”
As for bats, they face a similar problem with colliding with the turbines. However, the situation is even more grave than that of birds. One study examined this issue and found that 600,000 to 900,000 bats were killed by turbines each year. This is because bats, in particular, the Hoary bat uses trees as a landmark. The male hoary bat will locate the tallest tree and then circle it searching for a mate. However, the bats cannot distinguish between trees and the turbines and may run into the blades. Like with birds, biologists and conservationists recommend preventative measures. Wind turbines normally stay idle when there is no wind and turn on when the air reaches a certain speed threshold. Right now this threshold tends to be around 3.5 meters per second. However, bats don’t like to fly when it is overly windy. So, if wind farms up their threshold, especially during migration seasons, it could reduce bat fatalities by a staggering 43-93%. So, as long as wind farm take preventative measures such as these, there is no reason that wind power should negatively hurt bats in a significant way.
Overall, wind power is an extremely good non option for clean, renewable energy production. Of course no system is perfect. Wind energy is susceptible to changes in weather so it is not reliable at all times. It also does emit some particulate matter, which contributes to air pollution. Finally, wind turbines do pose a threat to wildlife in the area, especially birds and bats. However, wind farms are already taking steps to protect these creatures. Thus, most conservationists agree that wind power “reduces carbon emissions, pollution, provides jobs and economic growth, so [ despite the negatives, they] see it as a net positive.” For these reasons, wind energy has the potential to become one of the most crucial forms of energy world wide.