You can make them more efficient, or you can make them for less. (Picture from IBM.)
Most of the breakthroughs reported here focus on the first goal. The more efficient a cell, the smaller the area you have to cover in order to get a given amount of electricity.
But production cost is also important.
Most of today's efficient solar cells are made with rare materials like cadmium and indium. Gallium-arsenide or indium-selenide might convert 30% of the solar radiation striking them, but they cost big money.
Lights and mirrors can concentrate solar radiation on the cell, but now you're building a power plant, not installing a cell. Multicrystalline silicon also offers high efficiency, but they can be expensive to make.
A paper newly published by IBM aims to bend that cost curve in three ways:
- IBM's new cells are made of a popular low-cost materials list -- copper, indium, gallium, and selenide (CIGS -- cute acronym).
- They're relatively efficient, 9.7%. That's roughly a 50% improvement from other CIGS cells.
- As with new solar cells from Nanosolar, these are produced from a liquid slurry that can literally be printed.
IBM is not trying to get into the solar cell production business. They are looking to license the basic technology, and think they can get its efficiency up to 12% -- close to the low-end for multicrystalline cells.
Solar cell technology is becoming much like batteries, with breakthroughs piling on one another so that before one can get into production it's superseded by another.
But so long as any solar cell installation pays back its costs in a reasonable period of time, it can have value. We don't have to let the perfect be the enemy of the good.
A few years ago, on another blog, I suggested that the lack of standards for solar panels might hamper growth. I still believe that. But these new printed-panel techniques change the game somewhat. Such solar cells can be created to fit the space available.
We still need standard connectors, and upgrade paths. But the basis of solar technology is changing.
And rapid innovation is giving America a place in its future.