Alternative Energy Sources

Martin Barwise asked:




You have probably heard it said by environmental groups that we should switch to solar energy as a power source because it is free, there is an unlimited supply, and it is a cleaner source of electrical power because there are no by-products (compared to fossil fuels like oil and gas which release greenhouse gases into the earth’s atmosphere when burned for power.) However, can solar energy be a reliable and practical source of electrical power indeed?

When we use the term solar power nowadays, it usually refers to man-made technologies that rely on the flow of sunlight from our sun to create electricity or even mechanical power. Early pioneers in the conversion of solar power into usable forms of power were Auguste Mouchout, Frank Shuman, Charles Tellier, and John Ericksson. But the real breakthrough in conversion of solar power into pure electricity was achieved by the Bell Laboratories research team when they created the solar cell. Other people have been able to build on this development so that solar cells now have an efficiency of more than 40% and their prices have fallen to not more than $3 per watt.

Solar power technology is categorized as either being active solar, passive solar, direct solar, or indirect solar. One way solar power is directly used nowadays is to heat water for households. Solar power has an efficiency level of up to 86% when it is applied for creating hot water, which makes it a very attractive option for countries with cold climates where people find it hard to survive without hot water. Another way solar power directly affects our lives is when solar cells are integrated into everyday electronic gadgets such as calculators, or as a steady source of power for satellites in orbit around the earth. Households can now have solar panels installed on their roofs so that they can take advantage of sunlight to power their home. However, the demand for solar panels may be affected because of the shortage of refined silicon supplies.

The more cost-effective solution for large-scale use of solar power for power generation needs is construction of solar power plants. Solar power plants may either be of the older type of concentrating solar thermal power plant or the newer multi-megawatt photovoltaic facilities. The first kind, which relies on concentrating solar thermal technology, basically relies on mirrors or lenses to direct sunlight into a much smaller area of focus. However, this type of solar power technology can be disadvantageous to rely on when skies are overcast and there is little direct sunlight.

It is also interesting that solar power can also be used nowadays to power light vehicles. Proof of this is the biannual World Solar Challenge in Australia, where solar cars developed by researchers from both industry and universities have been able to reach speeds of up to 100 kilometers per hour during the race itself. Which is not bad, considering the speed limit for South Australia where the race is conducted is set at 110 kilometers per hour.

A very practical usage of solar power is to disinfect water supplies so that they become drinkable. Water can be disinfected either through solar water pasteurization or through solar water disinfection. Solar water pasteurization relies on solar power to make the pasteurization process work, involving sustaining application of heat to water for a certain period of time so that water temperatures stay within the 60 degrees to 70 degrees Celsius range. Solar water disinfection is a less intense use of solar power because the water is aerated first by vigorous shaking in a container which is then left to be exposed to direct sunlight.

All these uses of solar power indicate that eventually solar power may become a widespread source of power not just for large enterprises but also for the average human household. All that is required is for people to be able to afford the technology and its upkeep for solar power to become a practical and dependable source of power on a daily basis.

Solar Energy