Next Generation Wind Energy

June 28, 2013 by  
Filed under Green Energy News

Wind is the fastest growing energy resource in the world — faster than oil and coal which are non-renewable and contribute to climate change. Why? The costs are now competitive with new coal-fired power plants. Wind energy power purchase agreements (PPAs) are now being signed with utilities at prices under four cents per kilowatt hour. A friend at the American Wind Energy Association told me that some current PPAs are as low as $0.025/kwhr.

Amazingly, the 3-bladed computer-controlled, pitch-controlled wind turbines that are popping up everywhere today are largely unchanged from the basic mid 1970s WF-1 design of William Heronemus, Professor of Civil Engineering at the University of Massachusetts. Before Heronemus died, he invented its successor — a new kind of wind machine. These will cost about 2.5X less than current wind turbines. The details of the new machine and its promise are fascinating.

Captain William Heronemus started his career as the engineering and creative force behind America’s nuclear submarine fleet. Working under Admiral Hyman Rickover, he built nuclear-powered submarines that could stay submerged for many months, racing around the globe at speeds up to 38mph. Each had multiple ICBMs with multiple nuclear warheads and separate reentry vehicles. One sub could take out all the major cities in the world…and the Soviets never knew where ours were.

Having built so many subs, Heronemus asked Rickover if he could command one. Rickover eventually said yes but at 4 a.m. on the morning of departure, Rickover called Heronemus and said, “Bill you’re not going out today.” Heronemus asked Rickover if he was scrubbing the mission and he said, “No, it’s going out, but just not with you on it. ” Heronemus was standing on the dock as the sub departed.

The sub’s name was the USS Thresher. It sank on that voyage in 1963, killing all 129 on board. Shortly after, Heronemus quit the Navy and nuclear power to become one of the pioneers in renewable energy. I am co-author of two patents with Heronemus and worked with him for 27 years.

With its success, the UMass WF-1 technology was at the core of US Windpower Inc. which later became Kennetech Windpower. Kennetech was bought by Zond which was then bought by Enron. When Enron went belly-up, GE bought Enron’s Wind division and became the largest wind power company in the world. They are still using the technology developed by Heronemus at UMass — just bigger.

But bigger is not always better. Turbine blades are now up to 300 feet long and are hard to deploy. Think about how you would move an object the size of a football field through your town. Because the blades are cantilevered (supported only at one end) there is a huge amount of expensive and heavy structural material required to make a blade. And when the wind really blows strongly, the blade is blown back and can hit the tower, so they have to ‘feather’ the blades to spill wind, minimizing the power they harvest. These humongous wind turbines sit atop huge and expensive towers, but only one per tower.

Existing single rotor wind machines produce 90 percent of their energy output from about 30 percent of the swept area. The higher up you go the greater the wind, with very different wind regimes at the top and bottom of a wind machine. This creates an imbalance that manifests itself in lower than optimal efficiencies as well.

Think of the typical wind machine as a propeller driven airplane. And then along comes the jet. Or imagine the 1970s with large and larger computers and then along comes the PC; small computers could be linked together that were inexpensively mass produced. Each year these PCs got more powerful and reliable, and cheaper, easier and quicker to service or replace.

That’s how to think of next generation wind. This method uses a rotating tower which holds 12 or more smaller (but more efficient) wind machines. These units could generate the same power for 60 percent less cost than existing state-of-the-art wind machines. For the same swept area and wind, a multiple array spanning 80 meters would generate 6 megawatts (MW) compared to a single 80-meter diameter turbine of 2MW. Each turbine blade assembly could fit into the standard 40-foot shipping containers that are abundant everywhere. The tower could be assembled by the 75-ton cranes that exist at almost every building site in contrast to the back-ordered 350-ton specialty cranes used for current wind farm construction. The whole thing could be built from off-the-shelf parts. On land, the new rotating towers use tried-and-true 150 year old railroad boggie technology. Offshore multiple array wind towers are self-positioning.

Next-generation wind is not pie-in-the-sky. Bill Heronemus, who coined the terms ‘wind turbine’ and ‘wind farm’, and conceived the Cape Wind project (America’s first offshore wind farm) built a small scale 25-foot pilot seven-rotor wind machine and had it tested at NASA’s Langley Wind Tunnel. It worked like a charm with its performance reported on by Garrad Hassan, the world’s largest independent renewable energy consultancy. This shocked the wind energy community, whose standard practice is to site wind towers several thousand feet away from each other lest one turbine’s slipstream spoil the intake of its downwind neighbor.

WF-1 is now in the hands of the Smithsonian Museum and in April 2014 the University of Massachusetts will celebrate and commemorate its 40th anniversary. Although Heronemus passed away, his daughter, who worked with him, is anxious to invest her father’s next generation wind technology with a group that can fund and commercialize it.

Look at the rest of the articles in today’s paper and think about how many of the current issues would disappear (i.e. Keystone, fracking, Middle-East conflict, climate change and super-storms) if America were not still dependent on overseas energy and the world were not reeling from increases in fossil-fuel green house gases.

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