New research aimed at answering engineering questions for significant offshore windpower generation; many coastal states could meet most of their demand
By Bob Berwyn
SUMMIT COUNTY — The Gulf of Mexico oil spill is just the latest in a long list of signs that the age of oil is nearing an end. The simple fact is we can’t afford to continue poisoning the planet with gases that heat the atmosphere and toxic liquids that pollute rivers and oceans. As tragic as it is, the environmental disaster will help make even more people aware that our current energy path is not sustainable.
Earliest estimates for the cost of cleaning up the spill are in the range of $8 billion. What if that money had been invested in renewable energy before the spill?
Advocates of nuclear power also need to take heed, because they will one day face the same questions BP is facing now. As much as backers of nuclear energy would like us to believe — as they’ve convinced themselves — that they’ve resolved the engineering and technical challenges, they haven’t. It’s a lie. One day there will be a disaster involving a nuclear power plant, potentially with far worse consequences than the deadly oil slick spreading toward the Gulf Coast.
In the 52-page exploration plan and environmental impact study, BP repeatedly said it was unlikely, or virtually impossible, for an accident to occur that would lead to a giant crude oil spill and serious damage to beaches, fish, mammals and fisheries.
How many times have we heard the same story from the energy kings?
How often have they been wrong?
It’s easy enough to point a finger and criticize our country’s energy policy, or the oil companies, but that doesn’t really get us anywhere. Much better to use this teachable moment to try and achieve a fundamental shift in public attitudes about energy by presenting realistic alternatives. Yes, we will need to continue using oil for the foreseeable future, but we can set very realistic goals of replacing energy generated by fossil fuels with wind power. Overall, the U.S. already has a goal of generating 20 percent if its electricity needs with wind power by 2030.
It’s time to get specific and break it down. According to the U.S. Department of Energy, many of the 30 U.S. states with coastline could meet most or all of their electricity needs with a mix of land-based and offshore wind turbines. And the coastal states use nearly 80 percent of the nation’s electricity, so there’s potential to take a big bite out of oil, coal and gas consumption. In fact, the states with the greatest need for more electricity are those that would benefit the most from increased offshore wind power generation.
Just how big of a bite that could be isn’t completely clear, but we should soon have a better understanding of how large wind turbines built on deep-ocean platforms could contribute to the energy mix. With a $300,000 grant from the National Science Foundation, researchers with the Worcester Polytechnic Institute in Massachusetts will study the engineering part of the equation using computer models and water tank studies.
“For wind to play a significant role in meeting the energy needs of the United States, two considerations must be accounted for,” says Dr. David Olinger, associate professor of mechanical engineering at Worcester Polytechnic Institute. “The energy must be generated close to where it is needed and it can only be generated where the wind blows steadily. In particular, energy is needed to power cities on the east and west coasts, and the wind blows most steadily off shore.”
The U.S. has made significant progress in developing land-based wind power. Colorado is great example. But development of near-shore wind power resources has stalled, often over aesthetic concerns. The deep-ocean installations would address the concerns over visual impacts. And they’d be located where stronger winds blow steadily, the key ingredient for wind power.
Europe currently is generating about 65 gigawatts of power annually with more than 5,000 wind turbines. Many of those turbines are offshore, and more are being built all the time.The United Kingdom proposes to have enough offshore turbines by 2020 to power every home in the nation.
In some ways, Europe has almost been forced to look at the offshore wind power potential because of dense populations and high degree of urbanization. All of Europe’s offshore turbines are currently mounted on fixed-bottom, foundation-based towers in shallow water, less than 130 feet deep. But the world’s first deep-water, floating turbine, capable of generating 2.3 megawatts of electricity, is currently being tested off the coast of Norway and is expected to come online soon.
“Floating wind turbines, located far from land, would solve the environmental and aesthetic concerns associated with placing turbines near attractive natural beaches and coastal environments,” says Olinger. “They would be essentially invisible from shore while also being located in areas that provide greater wind power potential. Large sea areas, with stronger and steadier winds, are available for wind farm development.”
Olinger’s research is assessing the potential for developing offshore wind farms consisting of up to 100 floating turbines each capable of generating five megawatts of electricity (more than 60 percent larger than typical land-based turbines), or enough to power up to 500,000 typical homes. While the potential is immense, the obstacles associated with placing turbines weighing up to 15 million pounds atop towers as tall as 300 feet in deep ocean waters are significant, he notes.
“Before deep water turbines can be developed and successfully deployed, a host of questions must be answered so that they can be appropriately designed,” says Olinger. “How should they be transported to installation sites? What combination of platform and buoy designs, together with mooring solutions, will best stand up to major storms and large wave heights? How will environmental conditions vary from one ocean site to another?”
To address these and other questions, Olinger and his team are combining computer simulations with experimental modeling. “While computational modeling does a good job of handling forces associated with moderate waves and wind, nonlinear responses that will arise in storm conditions require physical modeling,” he noted.
For that, the WPI team is exposing scale models of deep-ocean platforms to simulated environmental conditions in the water flume test facilities at the historic Alden Research Laboratory in nearby Holden, Mass. Founded by George I. Alden, WPI’s first professor of mechanical engineering, this is the nation’s oldest continuously operating hydraulic lab. “The Alden facilities allow us to identify unexpected conditions and the need for alternate design modifications early in development,” says Olinger. “That means significant savings of costly changes further down the road.”
Already, the team has examined towing and transportation conditions. The impact of severe wave conditions on the scale models will be tested later. When the entire project is complete, Olinger aims to have a computer simulation program capable of testing a wide range of design types and potential environmental conditions. “Our work is fundamental,” he says. “If deep water wind power is to play a significant role in helping in the U.S. achieve its goal of generating 20 percent of energy from wind by 2030, the knowledge we are creating will be essential.”