Within days of its election, Britain’s new Labour government removed a de facto ban on new onshore wind farms introduced by the former Conservative government in 2015. The decision, which has been celebrated by environmentalists, represents an encouraging early step in the new government’s efforts to combat climate change, but it will likely cause concern for those who are suspicious of onshore wind farms. So, what’s the difference between onshore and offshore power and why have people objected to it?
How do wind turbines work?
Throughout history, people have tried to leverage the power of the wind for their own purposes. It is an excellent source of energy, albeit a tricky one to master. Modern wind turbines are just the latest expression of this effort. They work by turning kinetic energy from the wind into electricity.
Wind turbine blades are light and durable and are designed like airplane wings. They are attached to a hub and together they form a rotor. When the air moves across the blades, the rotor spins, which also turns something called a low-speed shaft. This shaft is also connected to a gearbox that converts the slow spin motion from the shaft into a high-speed rotary motion. This then turns a drive shaft that powers an electric generator.
What is onshore wind energy?
Fundamentally, there is no technological difference between onshore wind turbines and offshore ones. The only difference is the obvious: their location.
Onshore wind farms are collections of wind turbines that are installed in rural areas where there are strong and consistent wind patterns. Open plains, coastal areas, hills, and mountain passes tend to be good locations for them. Offshore windfarms are the same, they are just located in the sea and generate electricity from the wind that blows across the water.
When collected together, each turbine is positioned to optimize the capture of wind and to prevent turbulence from one turbine on another. Given the variations in topography, there are no uniform patterns for their layout, though there are some suggested optimal ones. They can be positioned in linear arrangements or grid patterns, depending on the context.
Regardless of their arrangement, each turbine generates electricity that is transferred to a substation, then run to the grid where its power can be accessed by communities.
What are the benefits and costs of onshore windfarms?
It is well known that offshore wind farms tend to be more efficient. This is because the sea experiences higher and more consistent wind speeds, requiring fewer turbines to produce the same amount of energy as onshore versions. The openness of the sea also allows for larger-scale projects – the more turbines you have, the more clean energy you’re generating.
The problem is that offshore wind farms are more expensive to build and maintain, as they need more complex infrastructure to support them. At the same time, the conditions that make them excellent electricity generators also make them a challenge to access when repairs are needed. They are also often owned by larger corporations, rather than local corporations, so there is less local oversight of them.
Onshore wind farms, in contrast, are easier to construct, they create fewer emissions, and the lands surrounding them can still be farmed. They are cheap to build and maintain, and their overall contributions to the grid can help lower electricity bills. At the same time, large-scale construction operations also provide more high-skilled jobs within the energy sector.
However, aside from them generating less power than their offshore counterparts, many people object to onshore wind farms for environmental and aesthetic reasons. The former relates to the fear that these structures pose a threat to birds and bats.
There is still debate within the scientific community over the extent to which this is the case. It appears that, although birds are killed by wind turbines, this number is significantly lower than the annual number of birds killed by housecats, other buildings, or even fossil fuel operations (the things wind farms seek to replace).
The bat situation has also considerable concern and has split the environmentalist community who, on the one hand, want clean energy to help combat climate change, but also don’t want to risk the lives of already endangered species of animals.
However, there are ways for onshore wind farms to be built to coexist with the surrounding wildlife. A decade of research has allowed wind turbine designers to find ways to make them visible to animals. At the same time, wind farms do not need to be constructed in areas where bats are nesting or swarming.
But this is only one solution. The problem with bats is they are actually drawn to wind turbines – they may be seeking nesting sites or trying to find insects – which has often led to their deaths. To combat this, the times and conditions that wind turbines are operated under can be shifted to accommodate bat behavior.
In particular, as light, fluffy, adorable things, many of the vulnerable species of bats killed by wind turbines cannot fly when wind speeds are above certain levels. By limiting turbine use when wind speeds are low, it is possible to dramatically lower bat mortality.
But the aesthetic objection is the most common one raised by the opponents of wind power. The concern is that the construction of wind farms in rural locations will be a blight on the landscape and will ruin its “natural” beauty.
Although this is a short-sighted objection, considering the overall damage unchecked climate change will do to the environment for future generations, it is also weirdly recurrent. Once upon a time, people objected to windmills for similar reasons, and now they are essentially iconic symbols of the same bucolic sentiments that underpin resistance to wind turbines today.
What is needed to make these new energy-generating structures palatable to aesthetic interest in the long run is a shift in the collective and local engagement with them as features of the landscape, rather than just corporate possessions that make money.
Source Link: Onshore Wind Farms: What You Need To Know