The sun’s energy is abundant. The amount of solar energy that reaches the Earth every year in the form of solar radiation is equivalent to more than 3000 times the annual world energy requirements!
Converting sunlight to electricity
Solar photovoltaic (PV) panels directly convert energy in the form of light from the sun into electrical energy. Currently between 4 and 22 per cent of the energy falling on a panel is actually converted to usable electrical energy, but this figure is increasing with advancements in solar PV technology.
Using solar electricity
Solar electricity is being used to provide electricity for houses all over the world with solar panels being able to tolerate a wide range of climatic conditions, including snow, frost, hail and high temperature.
In Australia, solar electricity is an option worth considering no matter where you live. The key requirements for a solar PV site are:
- A suitable roof or ground space that is not shaded during the day
- Space for other system components
People choose to use solar to generate electricity for a number of reasons. Historically, the main reason was lack of access to the electricity grid. A power system that includes solar panels can be ideal in this situation, as it may be substantially cheaper to install than a grid extension.
Since the mid-1990s it has been possible to connect domestic solar panel arrays to the electricity grid. Any electricity produced but not needed by the house is simply fed into the mains grid. The home can still, of course, draw electricity from the grid when insufficient electricity is being generated by the solar panels.
Many grid-connected systems have been installed by environmentally concerned home owners. As the cost of solar PV systems falls, and with electricity prices continuing to rise across Australia, people are now installing solar PV systems as a way to reduce their electricity bills.
Getting the angle right
Solar panels generate the most electricity when they face due north. The angles of latitude are: Sydney 34º, Adelaide 34º, Brisbane 27º, Melbourne 37º, Perth 31º, Darwin 12º, Hobart 42º
In the southern hemisphere, fixed panels should ideally be facing north and at an angle from the horizontal of the latitude at that location. This will ensure that the panels generate the maximum amount of electricity during the day. The Geoscience Australia website allows you to find the latitude of more than 250,000 place names in Australia, and will calculate the sun angle at any time of the day, on any day of the year.
However, orientation and tilt are not as critical as they used to be when panels were very expensive. A wide range of tilts and orientations will still yield 80–90% of maximum output. A few extra panels can offset any loss at a moderate cost.
- Feature image credit to ©iStock.com/lechatnoir