SINGAPORE - People have long dreamt of harvesting energy directly from the sun.
That dream became a reality when Bell Laboratories unveiled the first modern solar cell made of silicon 60 years ago.
And in Singapore, solar cells have been around for more than three decades, warming water for homes and generating electricity for bus shelters and a Pasir Ris fish farm.
In fact, the earliest research started long before a recent national push turned solar energy from a minor curiosity in Singapore into a part of a $1.7 billion clean-energy industry.
In 1839, French physicist Alexandre Edmond Becquerel first noticed small electric currents being produced when metals in an electrolyte solution were exposed to light.
More than a century later, researchers from Bell Labs, the renowned research arm of telecommunications firm AT&T in New Jersey, noticed the same effect with a silicon material.
The first modern solar cells were made of silicon doped with arsenic and boron, and were able to convert about 6 per cent of the light that hit them into electricity.
Today, solar photovoltaic or PV cells are typically made of a silicon semiconductor material containing deliberately introduced impurities to alter its electronic properties. The material absorbs some of the light that hits it, and electrons within the silicon cell are knocked loose and able to flow freely. The flow of these electrons is a current.
Initially, Bell Labs' solar cells were used to power telecommunications equipment in remote areas. By 1958, they had gone to space on the Vanguard satellites in the United States' space programme.
At first, the cost of solar cells was astronomical, at up to US$250 per watt of generation capacity in the 1950s, compared to about S$1 a watt today.
Even so, the 1979 energy crisis caused by the Iranian Revolution sparked renewed interest in solar energy around the world, including Singapore.
Many in landed homes chose to install solar water heaters, which do not generate electricity but simply heat water collected in a tank.
And in 1983, a floating fish farm off Pasir Ris, Marina Farm, installed a $6,000 set of solar panels to cut its $800 diesel generation bill by half, while the Port of Singapore Authority started using solar cells to power its navigational beacons.