Thursday, August 25, 2011
World Class Spin ?
By Henry Curtis
Castle & Cooke stated: "Our renewable energy vision includes harnessing world-class winds on the island of Lāna‘i." DBEDT stated: "The wind on Molokai and Lanai is some of the best wind in the world." HECO stated that "Hawaii has world class wind"
Fact Check: Does Lanai and Moloka`i have world class winds?
Scientists are investigating ways to harness the jet stream. Jet streams are area of strong winds ranging from 120-250 mph located 6-9 miles above the Earth. They can be thousands of miles long, a couple of hundred miles across, and a few miles deep. Within jet streams can be regions of especially fast wind, known as wind streaks. They can reach speeds of 300-400 mph. If fully harnessed, the energy in the Jet Stream could provide 100 times the energy currently consumed around the world.
Saffir-Simpson Category 5 hurricanes have wind speed exceeding 155 mph. Enhanced Fujita Scale EF5 tornadoes have wind speeds greater than 200 mph.
For the past 35 years there have been windmills in the Antarctic. Strong katabatic winds caused by the flow of cold air off the plateau make some coastal sites around Antarctica extremely windy. The Mawson Station in Antarctica may be the windiest place on the ground, with average wind speed of 23 mph and a maximum wind speed of 154 mph. (Potential for Significant Wind Power Generation at Antarctic Stations)
Wind speeds generally increase with height. The U.S. uses a wind classification system where wind is measured at 10 m (33 ft.), 30 m (98 ft.) and 50 m (164 ft.) above the ground level. The top category, Class 7, has wind speeds of 15.7 - 21.1 mph at 10 meters; 18.3 - 24.7 mph at 30 meters; and 19.7 - 26.6 mph at 50 meters.
According to the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) published the Wind Energy Resource Atlas of the United States: “In Alaska, high wind resource occurs over the Aleutian Islands and the Alaska Peninsula, most coastal areas of northern and western Alaska, offshore islands of the Bering Sea and Gulf of Alaska, and over mountainous areas in northern, southern, and southeastern Alaska. The largest areas of class 7 wind power in the United States are located in Alaska”
The Dakotas could produce 25% of the U.S. demand for electricity. “South Dakota possesses one of the finest wind regimes in the entire United States, with over 117,000 megawatts of generation, translating into over $250 billion of wind generation investment potential.”
“The Great Lakes Region represents one of the largest offshore wind market opportunities in the world. The estimated wind resource available for electricity production is 250 gigawatts (GW) – enough power for 75 million households. “
What about Hawai`i?
According to NREL: “On Oahu (Honolulu County), the  northeastern (Kahuku) and southeastern (Koko-head) tips of Oahu have areas of class 7  Molokai  much of the northwestern quadrant is class 4 or above, becoming class 7 at Ilio Point.  Lanai lies partly in the wind shadow of western Maui  winds are slightly accelerated (class 4) over the northwestern third of Lanai.  Hawaii [Island] consists of five major mountains and the saddles between them.  Trades diverted to the north of Mauna Kea accelerate through the Waimea saddle and over the Kohala Mountains, producing a significant area of class 7 wind power and a broad area of class 3 or higher wind power. A smaller area of high wind resource, up to class 7, exists at the south cape.”
DBEDT developed wind data maps for Hawai`i based on research by AWS Truewind and analysis by NREL.
There are two great areas of wind offshore of Hawai`i: the Moloka`i-Lanai Channel and the Pacific Ocean south of the Big Island. Each area has far greater wind potential than all of the Hawai`i land-based wind sites combined.
For land-based wind, the Kohala-Waikoloa area of the Big Island has the best on-land wind resources, followed by the Kaheawa-Ma'alaea area of Maui.
Lana`i and Moloka`i have rural, pristine, unpopulated areas that have wind. Where greed rules, development is always worth more than open “unused” areas. With a little spin like “the best wind in the world” some believe that Lana`i and Moloka`i resources should be exploited.
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