Slightly over a century that electricity became a commercial commodity, with the primary use to light up the streets. Today, there are so many ways we can use electricity and the number is still increasing. As there are more ways to use this source of energy, conventional ways of generating this power is not adequate in satisfying our growing needs and more ways are sought to bring us electric power.
We can get electricity from various sources: Coal, natural gas and oil, biomass, hydro generation, solar thermal generation, solar photo-voltaic generation, wind generation, nuclear generation, fuel cells, battery (dry or wet).
Most generations are from moving turbines. The fluid (usually steam) is first heated and then passed through the turbines at elevated temperatures and pressures so that maximum power is delivered. These turning turbines generate AC (alternating current) voltage. Before any long-range transmission, the electricity’s voltage must be stepped-up via means of a transformer so that the power lost in the transmission cables is reduced to minimum.
From the generation site, the electricity is delivered via cables to the distribution center, where the electricity is then distributed to various locations via cables or transmission lines. The power is then transmitted to the smaller substations via the distribution company/utility so that the elevated voltage is stepped-down again to 110V/230V suitable for consumers’ use. Via cables and wires, the electricity is transmitted to homes, schools, offices and etc.
In the case of hydro and wind generation, no boiling of water to generate high-power steam is required; the fluid does the rotating motion of the motor/rotor blades. It should be noted that hydro and wind generation is not as reliable is the sense that the generation capability depends on prevailing conditions like weather and tides. Hence, usually exciter, or capacitor and some other equipment are required to smoothen the voltage received from such generations. Alternatively, it may be stored in a battery for later use.
Solar thermal generation make use of the heat directly from the sun to heat the water for generation purposes, while Photo-voltaic generation generates DC (direct current) voltage from the sun/light source. It should be noted that DC voltage cannot be stepped-up or stepped-down for long distance transmission because step-up or down via a transformer via DC voltage is not possible.
Other than getting our electricity from generation, we can get our electricity in the stored forms – i.e. batteries. A dry cell is the common battery we get from convenience stores and they come in standard sizes like AA and AAA. Sometimes they are called alkaline batteries because of the chemicals contained inside. Reactions occur within these small gadgets to produce electricity. We can also get electricity from rechargeable batteries (like the ones in our mobile phones), usually made of metal hydride. The batteries have to be charged with the charger, which transforms our AC voltage to DC voltage possible for charging.
Wet batteries are bulkier, heavier and has a larger capacity compared to dry cells. Wet cells are usually used as car batteries, so that you can continue to listen to your stereo, and anti-theft system can continue to function even when the engines are turned off.
Whatever the source, or how we got the electricity, electricity is a very useful form of energy as it can be converted to other forms easily. It is so useful that we humans had taken it for granted. Oil crisis today had reminded us that this useful form of energy do come with a price tagged with it. Using it wisely is the most efficient method of utilising this source of energy.