General Electric is part of a group of investors that has put an additional $10 million in Southwest Windpower, a move that will likely be seen as a stamp of authority for the small wind business.

Southwest specializes in turbines that can generate approximately one to three kilowatts, but are small enough to put on residences or small industrial buildings. The company claims that the turbines can provide 40 to 90 percent of a home's power, depending on electricity use, the number of turbines, and the quality of the prevailing winds (see Small Wind Spreading Its Wings).

GE, which now rivals Denmark's Vestas for the top spot in wind power, mostly specializes in large onshore and offshore turbines. Some models can generate several megawatts of power. The company makes regular strategic investments and acquisitions in areas that it specializes in: water, smart grid, wind, etc.

Small wind has often been the crazy uncle of greentech: a nice idea, but impractical compared to passive systems likesolarpanels. A study by the Massachusetts Renewable Energy Trust found that at twenty-one sites, the projected power output was three times the actual power output. A green retrofitting contractor who installs small wind turbines recently described small turbines to us as "eye candy."

Nonetheless, the technology has slowly and steadily improved. The Massachusetts study noted that it wasn't the turbines that were at fault: it was how they were implemented.

When it comes to small wind, Southwest handily can be described as the leader. It has been in the market for around twenty-three years. Thus, it has been honing its technology far longer than newcomers like Magenn Power, Mariah Power or Makani Power. (Side note: While Southwest specializes in small versions of the three-bladed turbine, a number of the new startups are focusing on unusual designs. Sacramento-area Marquiss Wind Power has a fan-like device that it says pulls wind into the turbine to make it more efficient.)

Southwest predicted in December that volume shipments this year are expected to grow 90 percent to 100 percent in 2009 thanks to international expansion and tax credits in the U.S. In the U.S. the Federal government will provide tax credits up to 30 percent of the cost of small turbines. Even before the tax credits sales were growing: over the past four years volume sales have grown by 37 percent annually, according to the company.

Last year, Southwest linked a joint venture with China's Yun Sheng to start producing Southwest's Air X 400 turbine in early 2009. The joint venture, called the Ningbo Air-Yun Sheng Windpower, is expected to make 10,000 to 15,000 of the 400 watt turbines next year. The company also has started shipping products in Europe. The company next hopes to expand to the Middle East and Africa.