Windy days may be a welcome change from summer heat or a warning of the calm before the storm. Whatever its impact, it is almost always there in the background of our lives. Wind has been a great renewable energy resource for centuries and may only be getting better.
Not only can wind turbines work on land, but they are also ready for offshore use as well. Although there are some major differences between land-based and offshore wind generation, they both are important renewable energy resources.
The U.S. Wind Turbine Database records more than 67,000 wind turbines in America as of January 2021. Of that total, there are only two wind farms operating offshore in America’s coastal waters. Currently, 14 new offshore wind farms are in construction, but not yet fully operational. It is very apparent that land-based wind turbines have thus far been the favored location for wind-generation, but that may be changing.
The differences between the two are quite simple. The direction and origin of the wind is one primary difference. Additionally, land winds are stronger during night, while offshore blows stronger during the day.
Technology is much older for land-based turbines. The first wind-electric turbine was built in the late 1800s, so there has been a lot of time to work out problems. Block Island is the first fully operational offshore wind farm in the U.S., but it was not operational until 2016. People have started to invest more in offshore turbines because the wind is stronger and more consistent out at sea, though there is still a lot of development to do to make it more commonplace.
On land wind turbines are also much cheaper than offshore. Wind turbines can cost differently depending on their size and their ultimate purpose. For example, a commercial wind turbine can be from $2 million to $3 million. Farm turbines usually are much cheaper, around $3,000-$8,000. Offshore wind turbines on the other hand, can cost up to 3 times more than on land, according to the Institute for Energy Research. There are many factors that go into offshore wind turbines, these include more difficult construction and transportation of materials by water as well as storage or transmission of energy back onshore, so it makes sense that the cost would be significantly higher.
Even though they are different in terms of settings and strength, the functionality is the same way. Turbines blades capture kinetic energy from the wind as it passes through, causing the blades to spin. A generator within a box behind to the blades then converts the kinetic energy into electrical energy. That electrical energy is then passed through a transformer to change the voltage, to match it to the voltage used by the national electricity system. Once it has passed through that, it is onto the electrical grid and then ready to be used in the world!
There are many advantages to wind turbines as renewable energy. Once operational, they are emissions-free and have a relatively small physical footprint (although take up the most space of any energy generating source). The biggest problem with wind turbines is the potential of negative impacts on wildlife. There is evidence that wind turbines, both on- and offshore, are a danger to birds. There are collisions of course, but data on the impact to population-size is not conclusive.
Offshore wind turbines have a little bit more to worry about, as they are situated right in the ocean. Construction poses some threats for marine life, but the biggest problem is the sound that wind turbines generate during the construction. Many sea creatures rely on sound to get around and the construction can cause collisions, physiological, and negative behavioral impacts. Once the turbine is built, however, the noise has very little impact on sea life. On the flip side, the foundations of wind turbine farms can create new habitats for marine life. Algae can also attach to the foundations, which then could attract new sea creatures with the promise of new food. This may have future implications for maintenance, however.
In the end, climate change is the bigger threat to wildlife, so reducing greenhouse gases through projects like wind generation may be a small cost to wildlife in the short-term for longer term protection. Both onshore and offshore wind power is part of the toolkit for energy generation and climate policy. The specific projects and location may be up to policymakers, as well as landowners and the maritime industry, but knowing more about land-based and offshore wind will help make better decisions in the future.
Windy days are great for when it is too hot, and a breeze would be the most perfect thing in the world. But windy days are also great for giving the planet renewable energy, which will hopefully lead to many more sunny, windy days for people to enjoy.