Photovoltaics is the process of converting sunlight directly into electricity using solar cells. Today it is a rapidly growing and increasingly important renewable alternative to conventional fossil fuel electricity generation, but compared to other electricity generating technologies, it is a relative newcomer, with the first practical photovoltaic devices demonstrated in the 1950s. Research and development of photovoltaics received its first major boost from the space industry in the 1960s which required a power supply separate from "grid" power for satellite applications. These space solar cells were several thousand times more expensive than they are today and the perceived need for an electricity generation method apart from grid power was still a decade away, but solar cells became an interesting scientific variation to the rapidly expanding silicon transistor development with several potentially specialized niche markets. It took the oil crisis in the 1970s to focus world attention on the desirability of alternate energy sources for terrestrial use, which in turn promoted the investigation of photovoltaics as a means of generating terrestrial power. Although the oil crisis proved short-lived and the financial incentive to develop solar cells abated, solar cells had entered the arena as a power generating technology. Their application and advantage to the "remote" power supply area was quickly recognized and prompted the development of terrestrial photovoltaics industry. Small scale transportable applications (such as calculators and watches) were utilised and remote power applications began to benefit from photovoltaics.
In the 1980s research into silicon solar cells paid off and solar cells began to increase their efficiency. In 1985 silicon solar cells achieved the milestone of 20% efficiency. Over the next decade, the photovoltaic industry experienced steady growth rates of between 15% and 20%, largely promoted by the remote power supply market. The year 1997 saw a growth rate of 38%. This growth has continued over decades, and today solar cells are recognized not only as a means for providing power and increased quality of life to those who do not have grid access, but they are also a means of powering the grid, providing substantial fractions of the grid electricity in leading locations today.
The increasing market for, and profile of photovoltaics, means that they have become a huge business with more than 100 GW deployed each year. Photovoltaic systems are now often deployed with batteries attached so that the system can continue providing electricity even after the sun has set. The PV Education site aims to provide an overview of terrestrial photovoltaics to furnish the non-specialist with basic information. It is hoped that having used the PV Education site you will understand the principles of photovoltaic devices and system operation, you will be able to identify appropriate applications, and you will be capable of undertaking photovoltaic system design. By gradually increasing the number of people who are familiar with photovoltaic concepts and applications, we hope to increase the use of photovoltaics in appropriate applications.