By Jonny Lupsha, Wondrium Staff Writer
Commercial wind farms have been cleared for the California coast. Previously, the military objected to wind turbines as being “obstacles” for its ships. Harnessing wind is getting both cheaper and more effective.
Commercial offshore wind farms may soon pop up in central and northern California, as the federal government has adapted a plan to implement wind turbines in both areas. The U.S. military had previously voiced concerns over wind farms being obstacles for naval ships to have to circumnavigate, but it has since abandoned those concerns and given its approval for the development.
Despite not being a new technology, wind energy is still surrounded by myth and mystery. In his video series The Science of Energy: Resources and Power Explained, Dr. Michael E. Wysession, Professor of Earth and Planetary Sciences at Washington University in St. Louis, explained how wind turbines work.
Bernoulli and Air
“A wind turbine is like a plane propeller, but in reverse,” Dr. Wysession said. “Instead of an engine turning a rotor and generating a wind force that pulls the plane forward, the natural wind force blows through the rotors, generating a force that powers the engine. But the principle is pretty much the same.”
According to Dr. Wysession, both a wind turbine and a plane propeller work because of Bernoulli’s principle. Simply put, he said, Bernoulli’s principle states that a difference in air pressure will cause an object to move in the direction of lower air pressure. It’s not that the wind blows on a slanted blade, but that the blade is shaped in a way that the path of air around one side is longer than the other, which creates the difference in air pressure that puts Bernoulli’s principle into action.
“Wind turbines have benefitted greatly from advances in materials science,” he said. “Older industrial turbines used to have much smaller rotors than they do now because the metal of larger rotors would fatigue and crack. There’s an enormous amount of stress that gets applied to the blades and the shaft of wind turbines as the shaft turns, creating a rotational force called torque.
“However, the larger the rotors, the more efficient the turbine is.”
Pros and Cons of an Ocean Breeze
Dr. Wysession said that shoreline wind turbines are the fastest-growing sector of wind power since shorelines offer some of the best areas for strong, reliable winds. Additionally, the National Renewable Energy Laboratory of the U.S. Department of Energy predicted that offshore wind power alone could produce up to four terawatts of energy.
The United States currently consumes three terawatts of energy, according to the University of Washington’s Clean Energy Institute.
However, there are still difficulties associated with wind energy.
“The big downside of offshore turbines is [the] costs of construction—as well as operations and management—they’re much higher than for land turbines,” Dr. Wysession said.
Another issue that will have to be figured out, according to Dr. Wysession, involves exactly how to space out offshore turbines.
“One very important consideration for the deployment of wind turbines is that there’s a limit to how closely the turbines can be spaced apart before their efficiencies start to significantly drop,” he said. “A wind turbine breaks up the airflow behind it into a very chaotic pattern, and if another turbine is directly behind it, the efficiency of that second turbine—now stuck within the turbulent and chaotic airflow from the first—drops greatly.”
In the future, offshore wind turbines will have to be considerably spread out to remain efficient—and so the Navy can steer its ships safely around them.