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Wind turbines near Palm Springs, Calif., not far from a site where a 13-megawatt solar power plant is proposed. (Credit: Sunpluggers.com)

According to California solar power advocacy group Sunpluggers.com, wind turbines may be installed among the photovoltaic panels of a planned PV power plant in Palm Springs, Calif. This would be the first dual-purpose renewable energy plant in the U.S.

“What’s interesting about this renewable power project in particular is the non-coincidental nature of the two sources of power,” said Nathan Potter, a representative of the developer, AES Solar Energy of Arlington, Va., at a June 9 meeting of the Palm Springs Planning Commission. “The wind is generally strongest during the evening, and obviously the sun during the day.”

The project site is adjacent to high-voltage transmission lines and an electrical substation.

“What we’re doing is to plan on putting solar panels on otherwise useless land,” Potter told the commission, noting that the presence of the existing electricity system means the project “will forgo the need of further build-out of energy infrastructure.”

In addition to serving as a “test case” for combining the two renewable-energy sources, the project is an example of “how to do more with less,” he added.

Potter and other AES Solar representatives said the array had to be designed so that panels would not shade one another and could be economically congregated.

The project still awaits approval by state officials.

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A CalTech researcher believes some reconfigurations may allow vertical wind turbines to work more efficiently. (Credit: CalTech)

Researchers at CalTech have found that schooling fish unlock clues to better vertical axis wind turbines, which could yield as much as 10 times more energy from the same amount of space.

According to a press release, fluid-dynamics expert John Dabiri uses bioinspiration for coming up with better solutions for water and wind energy. According to Dabiri, schools of fish offer a wealth of insight into setting up better wind farms using vertical axis turbines.

“I became inspired by observations of schooling fish, and the suggestion that there is constructive hydrodynamic interference between the wakes of neighboring fish,” says Dabiri, associate professor of aeronautics and bioengineering and head of Caltech’s Biological Propulsion Laboratory. “It turns out that many of the same physical principles can be applied to the interaction of vertical-axis wind turbines.”

In current wind farms (nearly all horizontal turbines), all of the turbine blades rotate in the same direction. But while studying the vortices left behind by fish swimming in a school, Dabiri noticed that some rotated clockwise, while others rotated counter-clockwise. Dabiri, therefore, wants to examine whether alternating the rotation of vertical-axis turbines in close proximity will help improve efficiency.

The second observation he made was that the vortices formed a “staircase” pattern, which contrasts with current wind farms that place turbines neatly in rows.

With optimal placement, Dabiri thinks ten times more energy could be harvested out of the same wind farm using vertical instead of horizontal turbines.

“Our goal is to demonstrate a new technology that enables us to extract significantly more wind energy from a given parcel of land than is currently possible using existing methods,” says Dabiri. “We want to take advantage of constructive aerodynamic interference between closely spaced vertical-axis wind turbines. Our results can potentially make better use of existing wind farms, allow for wind farms to be located closer to urban centers-reducing power transmission costs-and reduce the size of offshore installations.”

Three of Dabiri’s turbines are being provided in partnership with Windspire Energy. In exchange for the use of the turbines, Dabiri will share his research results with the company.

Windspire’s website provides a short video promoting the vertical turbines.

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Back in June we reported on a futuristic design of wind power generators: vertical axis turbines.

Now researchers at the University of Virgina are developing a smaller, more efficient wind turbine uniquely designed to generate power in low-wind-speed areas. And they are building these turbines with a vertical axis, reports the Richmond Times-Dispatch.

The group is still seeking funding to create a full-size model that will have blades that extend 100 feet in diameter and spin along a vertical axis. Most wind turbines in operation today have much larger blades that extend up to 200 feet and spin along a horizontal axis.

“Most of the larger turbines are set for 14 to 15 miles per hour,” he said. “What we’re trying to do is get something that will work effectively in the 11 to 12 mph range.”

The design also will feature a turbine shaft levitated with magnets, which will reduce friction and consequently increase efficiency, says UVA mechanical engineering professor Jim Durand. Durand is also co-director of the Jefferson Wind Energy Institute

The overall design, Durand said, “is a combination of things that are aimed and optimized for low wind speeds.”

Paul Allaire, and UVA professor and the other co-director of the JWEI, will bring to the project his expertise on magnetic bearings. Allaire told the school’s newspaper, the Cavalier, in October that the goal is to first operate a 8-feet tall scale model in a wind tunnel that generates wind up to about 12 miles an hour. He said model was mainly a proof-of-concept step. “It’s very small and won’t generate much energy, so the plan is to build a 150-foot version, [which] would look like a cell tower.” The ultimate goal is to develop a system that can of produce 50 kilowatts of power.

Even with growing interest in wind power worldwide, the U.S. market for home wind turbines remains small, less than 0.002 percent of the national market. According to the American Wind Energy Association, however, this small wind turbine market is expected to grow dramatically over the next four years - from a total of 80 installed megawatts in 2008 to 1,700 MW in 2013. Already, installations in 2008 - 17.3 MW - marked a 78 percent increase over 2007.

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Via press release, Siemens has secured a contract to supply 70 wind turbines to one of Mexico’s largest wind farms, the Los Vergeles project, in a deal that marks its first major turbine order in Latin America.

Grupo Soluciones en Energias Renovables, a Mexican wind-energy developer, will pay Siemens $270 M for the SWT-101 turbines, rated at 2.3 megawatts each. The 160 MW Los Vergeles project will be built in the northeastern Mexican state of Tamaulipas.

“The Latin American wind power market is expected to grow significantly in the years to come,” says Andreas Nauen, chief executive of Siemens’ wind division.

The deal marks the largest order of Siemens’ new 2.3 MW turbine, launched in March 2009. The new turbine, which boasts a swept area of 8,000 square meters, is intended for use in low-wind areas. Siemens claims low-wind areas will soon account for one-third of global turbine sales.

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It’s not often that wind turbines malfunction to the point of destruction. Recently it happened twice in the same week.

According to the Copenhagen Post, in late October in Esbjerg, Denmark, a defective axle caused a 120-foot turbine to throw off all of its blades with one slamming into a power transformer. This was followed by an incident Nov. 2 in southwestern Sweden when another turbine — this time one from Vestas — threw off a blade that landed on a hiking trail.

Two Vestas in the U.K. also reportedly failed within weeks of each other in late 2007 and two more apparently failed in Denmark in early 2008.

Since 2000, there have been only 27 incidents in Denmark of turbine blades coming loose. However, as the rate of construction increases dramatically for this source of clean power, the frequency of turbine inspections is also coming under scrutiny. Denmark recently passed a law this year requiring inspections to take place at least once a year; and the wind turbine industry in Sweden has now proposed setting up a commission to investigate incidents.

Note: Video above is from a turbine that malfunctioned in Denmark in early 2008. The turbine was not designed to spin this rapidly, and the rapid spinning indicates a probable brake failure.

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