History Of Solar

The Long History Of Solar Cells

Solar_PowerWe often like to take a look back on the history of the development of solar cells and new technology in that area.  We have come a long way!


The industry’s problems lie in the fact that although costs have been dropping steadily, current state-of-the-art solar cells are still very expensive. Over the past quarter century, the cost of producing and installing cells capable of generating 1 watt of power has fallen from about $1000 to between $8 and $12. In spite of that spectacular achievement, photovoltaic power is still too costly to compete with other forms of energy, except in relatively limited applications such as running machinery in remote areas where there is no electric grid. Every drop in price expands the potential market, but most analysis believe that costs will have to get below $2 per watt before the market really takes off.


To get to that point will require a change in technology. Today’s power cells are mostly made from crystalline silicon that is formed into single-crystal rods, or cast into ingots, and then sliced into thin wafers. Although relatively straightforward, the process uses large amounts of material, much of which is wasted in the slicing stage. A less materials-intensive process, in which molten silicon is formed directly into ribbons of crystals, is under development by several companies, and others are using lenses to concentrate sunlight on the cells and boost their output. These technologies and refinements in manufacturing techniques may shave the price of solar cells still further, but in the long term, the future of the photovoltaic industry is not expected to lie in crystalline silicon.


The really low-cost cells are expected to use ultra-thin films of photovoltaic material deposited on a substrate such as glass or steel. Several candidates have emerged for this technology, but most investors are putting their money on amorphous silicon. Although amorphous silicon is less efficient than the crystalline form in converting sunlight into electricity, cells made from the material are expected to be so much cheaper to produce that the lower efficiency can be more than offset by increasing the area of the solar panel. More development and large-scale production is needed, however, before the full cost reductions are realized.


ARCO Solar, the world’s largest producer of crystalline silicon cells has an aggressive R&D program on amorphous silicon, and “we have guessed that will be the way to go,” says James Caldwell, Jr., the company’s president. Solarex, the third largest U.S. photovoltaic company recently bought the rights to amorphous silicon technology developed by RCA. And several smaller firms–notably Energy Conversion Devices of Michigan and Chronar Corporation of Princeton, New Jersey–are concentrating exclusively on amorphous silicon. Zoltan Kiss, president of Chronar, recently predicted that his company will be producing amorphous silicon cells for less than 50 cents a watt by the end of this decade. This U.S. enthusiasm for the technology is more than matched by Japanese companies, which are banking on amorphous silicon for the future and are already producing substantial quantities of the cells for specialized markets.


Although just about everybody agrees that there is a bright commercial future around the corner for thin-film cells, the problem is how to get from here to there. The traditional business strategy would be to use profits from current operations to finance R&D and attract capital to establish production lines for the next generation of the technology. But nobody is making much of a profit on photovoltaics today and generating capital for future development is therefore tough. Kiss put it bluntly at recent hearings held by the House Committee on Science and Technology: “the U.S. photovoltaic industry has operated at a loss for the past years and its future is in jeopardy.”


In addition, the industry has had to contend with high interest rates, which have made it extremely expensive to raise capital, and the soaring value of the U.S. dollar has made it difficult to compete with foreign suppliers in export markets. The global recession has also caused many would-be purchasers of solar cells to delay their investments, and oil prices have declined, making photovoltaics even less cost-competitive.


As a result, several companies including Exxon, Martin Marietta, and RCA have recently quit the business and those that are left are increasingly dominated by oil companies, which can afford to carry losses for a few years. For example, ARCO Solar is a wholly owned subsidiary of Atlantic Richfield, Solarex was recently bought out by Standard Oil of Indiana, and Energy Conversion Devices is largely being bankrolled by Standard Oil of Ohio.

Norman, Colin. “A cloudy forecast for solar cells.” Science 226 (1984): 319+.