When most people hear the words "solar energy," they think of expensive power towers or under-performing photovoltaic panels. California-based LightManufacturing LLC offers manufacturers a new way to use solar energy to mold plastic products sustainably and inexpensively.  

Each year manufacturers rotomold more than 3.6 billion pounds of plastic into large consumer and industrial products. Traditional rotomolding requires massive, expensive machinery, and large natural gas heated ovens. The process emits more than two billion pounds of greenhouse pollution annually. Energy to fire the ovens contributes up to 30% of the total cost to make rotomolded products. 

In contrast, LightManufacturing's solar rotomolding (SRM) systems use the sun's heat to make the same products at significantly reduced costs – and with zero carbon emissions. In the patent-pending new approach, specially designed heliostats (sun-tracking mirrors) aim sunlight at low-cost molding armatures. Small SRM factories can be placed close to customers, creating additional savings by reducing transport costs. SRM systems operate entirely off-grid, requiring no outside electricity or fuel.

LightManufacturing CEO Karl von Kries came up with the idea for solar thermal rotational molding while working with a traditional rotomolding factory in New England.   

"I was out in the plant with these machines," von Kries says, "and it struck me as an inherently wasteful process. I thought, 'Why couldn't we do this with solar heat?'"

After years of research and development, von Kries founded the company in 2009 to make solar thermal rotational molding a reality. Today, LightManufacturing has a working test facility in California that makes plastic parts for customers. 

The company also developed a new type of low-cost heliostat, which replaces expensive glass mirrors with thin reflective plastic stretched flat like the head of a drum. The firm anticipates shipping ready-to-use solar rotational molding systems and heliostats to customers by August 2012. 

"I cannot think of another process like it. When is the last time you heard of a solar solution that is cheap to buy and operate, solves environmental problems, does not depend on subsidies, and makes the market more competitive?" von Kries adds. 

For those worried plastic products cannot be green, LightManufacturing notes that its systems mold recycled plastic and sustainable bio-plastics just as well as oil-based plastics. 

The firm sees rotational molding as just the beginning. LightManufacturing plans to bring solar thermal-powered technology to other industrial manufacturing processes, such as injection molding, blow molding, agricultural applications, and more. 

"We are in the very early days of applying solar thermal energy to industry – and the potential is huge," von Kries concludes.