HelioVolt announced today that it has produced solar cells through a rapid printing process that have a 12.2 percent conversion efficiency. And HelioVolt has announced that the six-minute printing process is scalable.

HelioVolt’s process creates thin film cells — cells with significantly reduced material needs for converting solar energy to electricity. The problem with thin film cells is that they generally have much lower energy conversion efficiencies — that is to say, they just don’t generate as much electricity from a given amount of light. Most commercially available cells are between 5 and 19 percent efficient, and thin film cells are generally on the lower end of that spectrum. If HelioVolt can offer up a 12.2 percent efficient thin film cell, we’re talking about a significant increase, and the company says that Colorado State University has completed independent testing to confirm their result.

A key issue with wide scale solar cell use has been the high cost of production in both time and materials, and the very low return on that investment. While technology has advanced beyond the point where the energy payback is actually negative — a big problem in the 90s — so far, solar cells simply haven’t been cost effective.

But HelioVolt’s rapid printing process, combined with thin film technology seems to promise a much cheaper product. And that 12.2 percent efficiency rate could make it practical to invest in a few solar cells to power an office or home. There are a couple of concerns that I have about these cells at this point, though:
 

• Rapid printing is fast and cheap, but it doesn’t always make for a product that can hold up over time. It can take a significant chunk of time for a solar cell to save a user enough money on energy that it actually covers the cost of the cell.
• HelioVolt is manufacturing copper indium gallium selenide (CIGS) cells. While you can run down to your corner hardware store and pick up copper, indium is much harder to come buy. Right now, according to the US Geological Survey (PDF), 70 percent of indium produced goes directly to the flat-screen monitor industry. Even if solar cells manufacturers could get their hands on more indium, it may not be enough to maintain the industry. Indium can be recycled from old products, but it’s still a concern.

Overall, HelioVolt’s announcement has great potential. Cheap solar cells are a sort of energy Holy Grail at the moment, and HelioVolt seems to be just about there.

Photo — Reiner Kraft