In Australia, over 20% of households have solar panels
installed. Although solar technology is making vast improvements in performance
efficiency; the efficiency level is still between 11 -22%. This means that only 22% of the Sun’s energy
is converted into electrical energy.
A solar panel collects sunlight and converts it into
electrical energy. There are a few reasons why efficiency can be lower on any
particular day. Weather and seasonal
factors cause the most variation in how much energy output you will receive in
a day.
The length of day is the major contributor to how much
sunlight a panel will receive, and therefore how much energy it can produce. In
Australia, there is not much variation between the length of day in winter and
summer (only about 2.5 hours). However,
the further away you are from the equator the greater the difference will be. For
example, in Iceland it doesn’t get dark at all in their summer compared to
winter where there are only a few hours of sunlight. Even with a battery, there would not be enough
solar energy generated in winter to be relied upon as a sole energy source.
Latitude_and_longitude,
accessed 30/4/2020
The amount of light the panel receives is also an important
factor. There are a few reasons this can vary throughout the day. One major
consideration is the angle that the solar panel is placed at and its position
on the building. Solar panels are installed to ensure they capture the maximum
sunlight for their geographic location. The angle of the panels will be
different, adjusted for latitude.
Eyafjallajokull,
accessed 30/4/2020
The weather is also a key contributor to the efficiency of a
solar panel. The clearer the sky, the more light a solar panel will receive.
This means that a cloudy day will greatly reduce the amount of energy the panel
receives and produces.
A common misconception is that temperature effects the
efficiency of a solar panel. It seems natural to think that on a hot, sunny day
you will be getting optimal output from your solar panels. However, as the temperature rises the
efficiency decreases. This is because the wires in the panels heat up, making
the atoms in it vibrate more. This makes it harder for the electrons, which
provide the electrical energy, to pass through. In simple terms, as the
temperature increases the resistance also increases, making the panels less
efficient. This means a clear day in winter may generate more electricity than
a hot day in summer!
- Try this experiment to see if your results agree.
- Investigate how electricity flows with this simulation.