Traditional solar panels are one of the best investments you can make toward an energy-efficient home, but for many homeowners their appearance leaves something to be desired. However, a new generation of  “thin-film” solar cells are much more flexible, and can be placed on windows, walls, and even curved surfaces. As the technology advances, and new manufacturing plants are built, thin film could represent the next big wave in solar energy.

Although thin-film solar cells generate less power in the same area than traditional solar cells (this is where the technology needs to improve), they also require much less polysilicon, a material that is currently in short supply. Silicon accounts for 40 to 50 percent of the cost of conventional panels, which require 200 times more silicon than thin film. The thin film technology is based on CIGS (copper indium gallium selenide) and is arranged on a flexible backing, so it can be installed in places that traditional panels cannot -- the sides of buildings, tinted windows, cell phones, notebook computers, cars, and even clothing. The thin film surfaces are also more durable and attractive than traditional panels.

Thin film cells could account for up to 30 percent of the global solar cell market by 2010, from around 7 percent in 2006, Taiwan's E-Ton Solar estimates. Major solar energy companies such as Germany-based Q-Cells are anticipating big growth potential for thin film surfaces. Sharp Corp. plans to boost its thin film solar cell production capacity from 15 megawatts a year to 1,000 megawatts by 2010 with the construction of a massive plant in Sakai City, Japan. In the US, Nanosolar has become a major player in thin film solar,  and the company is building a production plant in California that is expected to be one of the biggest solar cell makers in the world.