As non-renewable energy sources are used up, it is becoming important for people to find alternative sources for their homes. Prices are likely to rise higher and higher as non-renewable sources of energy become rare. The Energy Information Administration in the USA has suggested that if just four percent of the worlds desert were covered in solar panels then the power requirements of the entire world would be taken care of.
How does solar energy work?
Its all about the sun! Photovoltaic cells turn the heat from the sun into electricity by releasing electrons in the cells. Usually a photovoltaic cell is made from a semi-conductor material. When electrons are released in the cells they are attracted to a positively charged element in the cell, and the movement of electrons across the cell creates a direct current (DC). The direct current can be stored in the cell or transferred to an alternating current (AC).
Different types of solar energy systems
Currently solar energy is most effective in areas where there is a reliable amount of sunlight during the day. This does not mean that solar energy is only effective in sunny climates, however. Some systems can be used to store electricity that is generated during the day in a battery and then release that energy at a later time. These systems are useful as the majority of the electricity used during the world occurs after the sun goes down. Other systems are connected to the National Grid. These systems take energy supplied from the sun and use this energy first to power the home; any excess energy is supplied to the Grid.
How effective are solar panels?
Effectiveness is determined in a slightly different way to traditional energy systems - although the numbers are expressed as a percentage. If an oil fire is 75% efficient, this means that it converts 75% of the fuel to useful energy; meaning that 25% of the usable energy is 'wasted'. However, if a solar panel is 75% effective this means that 75% of the solar energy is converted to electricity, however, there is no wasted energy as the solar energy is free of charge to the user. Modern solar panels have an efficiency rating of about 40%.
The future
Technicians are working to create solar panels that have double the current efficiency rating. These new panels work in a similar way to conventional solar panels. The Earth absorbs energy from the sun during the day and releases it during the night. This energy is released as infra-red radiation during the night. New solar panels will be able to convert sunlight to electricity during the day, and harness the power of infra-red radiation during the night. Many street lights and small electrical systems are already running on this type of power. With recent developments in technology, this trend is set to continue as more and more of our electricity is generated from cost-effective solar energy.
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