

GreenVolts seeks to be Apple of high-end solar


Greenvolts' concentrating photovoltaic system is designed all custom components to optimize performance and lower the cost of power generation. GreenVolts



The solar industry is undergoing a brutal price war driven by the rapidly falling price of conventional silicon solar panels. GreenVolts has designed a concentrating photovoltaic (CPV) system, where powerful Fresnel lenses focus light onto several super-efficient solar cells the size of a finger tip.

It's also making a break with conventional CPV design by custom building every component that goes into a solar generation station, including the optics, tracker, inverter, and management software. An integrated design approach, similar to the way Apple designs products start to end, lets GreenVolts compete well on price, according to David Gudmundson.

"Because we have control of every aspect, we can optimize every component in way that's not possible in a disparate component-based approach," he said. For example, because the inverter and solar collector can communicate with each other, they can automatically improve the tilting to maximize power generation.

Its large solar collectors are mounted on a pole structure that has motors to point the panels at the sun at all times. Its software pulls data from all components of the system, giving operators more visibility into power production and maintenance, said co-founder Eric Romo, who is vice president of strategic development.

The systems are targeted at commercial customers or utilities looking for distributed solar systems from about 500 kilowatts to multiple megawatts in capacity. So far, it has been installed in about 12 locations, said Gudmundson.

CPV systems are designed for parts of the world with lots of direct sunlight, such as desert areas in the southwest U.S. There are a handful of installations in the U.S., including a 30 megawatt Cogentrix plant backed by a Department of Energy loan guarantee in Colorado.

In terms of cost, GreenVolts executives say its technology can compete with today's flat solar photovoltaic panels, which have fallen in prices by more than 50 percent over the past two and a half years.

GreenVolts believes it can keep pace with falling costs in traditional PV because the high-efficiency gallium arsenide solar cells it uses are gaining faster in efficiency than solar-grade silicon or thin-film materials.

"Cell efficiency is in our favor. They're about 38 or 39 percent effient now, but the cell road maps all go into the 40s," said Romo, adding that the optics can improve as well. Most CPV lenses concentrate light several hundred times.

The company, which was founded in 2005, has raised $120 million to date. Many energy start-ups have sought out partnerships with large corporations, such as ABB, Siemens, or General Electric, to gain access to their capital, energy industry contacts, and manufacturing expertise.

"The technology combines simplicity and precision with unmatched performance, fast installation, easy operation and low cost of production," said Peter Leupp, head of ABB's Power Systems division said in a statement. "Our extensive footprint, which covers all key solar markets in the world, will help us to make this technology globally accessible."

One unique aspect of its system is the two-axis tracking system which rotates collectors to face the sun. Underneath the collector on the left, one can see the heat sink for the high-efficiency cell which is about the size of a finger tip. GreenVolts