They make cool three-dimensional stickers, they are projected as images in air and they even helped R2-D2 convey Princess Leia's message to Obi-Wan Kenobi. Now, holograms also could help make solar power more affordable.
Prism Solar Technologies, in Stone Ridge, N.Y., has developed a solar-concentration technology based on the use of holographic film, calling it "Holographic Planar Concentrator" technology. The film is sandwiched between two pieces of glass, where the hologram traps incoming sunlight and selectively channels the spectrum to silicon-based solar cells.
In a presentation at the Cleantech Forum in Toronto last week, CEO Rick Lewandowski said that by directing the incoming light to specific cells, fewer cells are needed. He added that a typical panel could use 27 percent to 60 percent fewer solar cells. The result is dramatically less need for silicon, and modules that he predicts can generate electricity for $1.36 per watt.
The ability to use less silicon is particularly attractive in a market grappling with a worldwide shortage of silicon, and the potential to cut costs is an important factor as the solar industry tries to become competitive with conventional electricity.
Investors apparently think so, too. Prism announced Monday it was selected as "Most Promising Technology" by investors attending the Cleantech Forum.
The hologram performs many functions, Lewandowski pointed out. It can capture and direct sunlight from any direction, meaning no need for panels to be on mechanical tracking equipment. By selecting the spectrum it needs, the film can manage cell heat better. It also has the ability of directing sunlight to both the front and back of a cell, a bifacial approach that taps more of a cell's silicon surface, nearly doubling cell output.
While the concept of using holograms to boost solar cell output has been around for a couple of decades, no company has yet managed to commercialize products based on the approach.
Lewandowski said the company has just closed a $6.5 million round of financing and is looking for another $6.3 million by year-end to help fund a 60-megawatt solar module facility and a 240-megawatt production line for Prism's holographic film. Investors to date include CounterPoint Ventures and Phoenix-Fire II.
Prism operates a lab in Tucson, Ariz., and a pilot line has produced 27 systems that are being tested in the field.
Energy Innovations, Stellaris, SolFocus, DayStar and Soliant are among a number of companies developing so-called solar-power concentrators. The technology, based on mirrors and lenses, can increase the amount of light that hits a solar cell by more than 100 times, but the systems are complex and can heat up. They also require mechanical tracking of the sun, making them less attractive for residential installations.
Prism's holograms only boost light tenfold, but Lewandowski said the company's approach is more practical because it doesn't require heat management or active tracking, making it ideal for residential, commercial and utility-scale systems. The product also has the potential of integrating with doors, windows and other parts of buildings.
Still, challenges remain. None of the concentrating solar-electric technologies in development have significantly lowered cost barriers or reached the mass market. Some analysts says commercialization is years away and that concentrating companies might lose their market if the silicon shortage ends before they reach large volumes.
Lewandowski said Prism still offers a compelling approach even if the silicon bottleneck eases up. "This is largely about the film processing," said Lewandowski, explaining that the film can be used by any solar PV developer looking to lower their costs and increase efficiencies. "We believe this technology can be leveraged through this entire industry," he adds.
If the company can demonstrate the technology works, and can produce it in large volume at lower cost, it could find itself in a coveted position -- and ahead of the curve -- in an industry racing to provide grid-competitive solar power.