Compiled by Janani Amarasekara

Solar power for cleaner energy

The Sun, as you all know, is the main source of energy in the world. Plants get the sun's energy through the process of photosynthesis, then the cycle of energy begins to rotate. Nowadays, people tend to use the energy we get from the sun, known as solar power, because it doesn't pollute the environment, and unlike other power supplies like fossil fuels, it's unlimited.

Solar power is defined as the technology of obtaining usable energy from sunlight. This has been used for centuries. Solar panels are found on roofs, which are more exposed to sunlight.

Solar energy is currently used in heating (hot water, heating buildings and cooking), electricity generation (photovoltaic and heat engines) and desalination (removing the salt) of sea water. Spacecraft also use solar power to get energy.

Many technologies have been developed to make use of solar radiation. Some of these technologies make direct use of the solar energy to provide light, heat or electricity. Solar designs can be used to achieve comfortable temperature and light levels with no additional energy.

Even in Sri Lanka, solar power is used to provide electricity to rural areas which are difficult to reach through electricity wires.

Though the initial payment for solar panel installations is a bit expensive, it provides long-term benefits. It is not sunshine that charges the panel, but the rays from the sun. So, even if it is gloomy, there's no cause for worry. Photovoltaic panels currently convert about 15 per cent of incident sunlight into electricity.

But, we may face a problem in the future because of global dimming, an effect of pollution, that is allowing less sunlight to reach the Earth's surface. So, it will reduce the existing and potential available solar power.

The order of magnitude is about four per cent less solar energy available, at the sea level, over the time frame from 1961 to 1990, mostly from increased reflection from clouds back into outer space.

Solar cooker

A solar box cooker traps the solar power in an insulated box; such boxes have been successfully used for cooking, pasteurisation (see In the limelight of October 29) and fruit canning.

This is used in many developing countries, both reducing the demands for the local firewood and LP Gas, and maintaining a cleaner environment for the cookers.

The first known solar oven is attributed to Horace de Saussure in 1767, which impressed Sir John Herschel enough to build one for cooking meals on his astronomical (enormous) expedition to the Cape of Good Hope in Africa in 1830.

Solar lighting

Solar lighting is the use of natural light to provide illumination. Solar lighting offsets the energy used in electric lighting systems. Although difficult to quantify, the use of natural light also offers physiological benefits.