Solar Basics

Did you know?

• The Earth receives as much energy from sunlight in 20 days as is believed to be stored in the Earth’s entire reserves of coal, oil and natural gas
• Some 2,000 years ago the Greeks used mirrors to focus the sun’s rays on Roman ships, causing them to catch fire
• There are presently three main types of solar power system: solar buildings, solar thermal concentration systems and photovoltaic cells. The latter were first developed for the United States’ Space Program.
• The term photovoltaic comes from the greek “phos” which means light and “volt”, from the scientists Alessandro Volta. In other words, photovoltaic literally means “light-electricity”
• With today’s technology, houses with passive solar design and efficient insulation can save as much as ninety nine per cent of energy used for space heating and cooling.
• Each year the sun delivers to the Earth enough free energy to light twelve million million 100 Watt light bulbs all at the same time

From Ancient Greece to the Space Age - harnessing solar power through history

We owe our very existence to the power of the sun. Through solar technology, we can also harness its abundant energy to improve our quality of life.

In battle, the Ancient Greeks used mirrors to direct beams of sunlight onto Roman ships, which subsequently burst into flames. They also designed homes to absorb solar heat so effectively that they were protected from extremes of hot and cold, using what we now refer to as passive solar design.

How far have we come since then?

Despite the inventiveness of the Ancient Greeks, subsequent generations failed to develop solar technology until the end of the eighteenth century, when a French chemist named Anton Lavoiser built a solar furnace that achieved temperatures of 1,750 degrees Centigrade. In the late 1800s, Augustin Mouchet then devised several solar-powered steam engines.

By the early 1900's, solar power was widely used in the southern United States in water heaters. These systems fell from favor when cheap oil and gas became available in the 1920s. While the solar industry received a reprieve through the soaring energy prices of the seventies, it was not to last.

How do we use solar energy today?

We currently employ solar technology in three different ways:

• Passive, through solar buildings as pioneered by the Greeks
• Active, through solar thermal concentration systems that collect the sun's heat
• Photovoltaic cells, which use light to generate electricity directly and were first developed for the United States' Space Program.

In recent years the fortunes of the solar industry have improved greatly, as governments and businesses respond to pressure for greener energy alternatives to fossil fuel.