Invented at Bell Labs 50 years ago, power via photovoltaics, or solar cells, has left its mark on a wide range of applications that most of us take for granted now. In its infancy, solar cell technology found its first economical use in remote applications like space satellites, then later stayed alive by playing in niche markets like remote offshore power and oil production and mountain-top relay stations. More than half a century has gone by and the world of photovoltaics has seen impressive strides, with the market growing at a rate of 35 % a year.

Solar cells in space

The PV power systems currently on the market have developed over the course of forty years, with the space industry being its very first frontier. For the first twenty years (1960 to 1980) solar cells were used to power spacecraft in orbit, in lieu of other possible power sources. These early years developed important attributes of the cell such as reliable contacts, encapsulants, optical properties and test standards. My first spacecraft job, at Boeing in 1965, was testing the Lunar Orbiter spacecraft, powered by solar cells from RCA Mountain Top in Pennsylvania. In the 1960s solar cells were just another diode on the production lines at RCA, TI, Motorola and Hoffman. In 1967 I left Boeing and became president of Spectrolab as America went to the moon. The Apollo 11 landing on the moon in 1969 left behind a Spectrolab solar array powering a seismic monitor. The solar powered unit remained operational for several years until NASA turned off the transmitter.

The cost race begins

The next ten years (1980 to 1990) saw an expansion of solar cells, from their use in space, which was a relatively small market, to a number of terrestrial applications including remote-power markets such as offshore oil platforms, pipeline instrumentation, remote landing-strip beacons, mountain-top communications repeaters, etc. Most of this market involved charging batteries in remote locations. Just like the spacecraft application of solar cells, remote power systems operate unattended. All through these early 30 years, the growth rate of the PV business was a healthy 25 % per year or more.

I started Solar Technology Inc in 1975 with one goal: To make much lower-cost solar panels for industrial use. My first solar panels produced 20 W for charging a 12-volt battery and sold for $300. So the cost metric of $15/W began to be used to compare terrestrial solar panels. Since then, the push has been to reduce cost but retain the reliability the space business taught us. I sold my company to Atlantic Richfield in 1978 and we renamed it ARCO Solar. Two years later, we finished building a new factory in Camarillo, CA, which still remains the largest plant in the USA. This plant mass-produced large, 35 W, panels that sold for $300 and reduced the price from $15/W to $8/W. In 1987 ARCO eventually sold the company to Siemens Solar, and in 2001 Siemens sold it to Royal Dutch...