How Many Solar Panels Do I Need
For most of us, when someone talks about renewable energy, we think solar power. We often visualize those shiny
blue or black panels resting atop the roof.
True, it’s those panels that trap sunlight, which is then converted into electrical energy. Sometimes they are
also called photovoltaic plates or modules (PV modules).
Solar power has been at the core of renewable energy for years and, although the technology was discovered over
a century ago, its widespread adoption has been very gradual.
Solar panels are the backbone of any solar electric system. The size and number of panels used are key factors
in determining how much energy a system can generate. Nonetheless, there are many variables that are interrelated
and its not possible to determine the number of panels you need without estimating some other important values
Find out your power consumption
You need to determine the number of kilowatts you expend in your home on a daily basis. Obviously, reading your
meter should give you a rough estimate but if you don’t want the hustle of dealing with meter readings, have your
statement sent to you by the utility company. If that is still hard, make use of online resources or national
average estimates, depending on where you live.
Determine how much sunlight you get per day
You also need to know the quantity of sunlight your area receives. To get the average for the peak amount
absorbed per day, you get the value for annual average and do the maths. Its good to take a conservative approach
when estimating this value. As with power consumption, there are online resources that can help you make these
Find the number of panels
With the value for power consumption and average peak sunlight, you are now able to determine the number of
panels you need. Solar panel rating is in watts - for instance, a 50-watt panel will generate 50 watts of
electricity every hour of peak sunlight. First, you’ll have to calculate the number of watts you need to generate
per hour; divide total daily watts consumed by the amount of sun received in a day (hours).
If, for instance you need to generate 100 watts per hour, then you’ll need two 50-watt panels. Keep in mind that
panel ratings vary. You also ought to know that most people use solar to complement another source, such as
Note that orientation of the panels greatly determines their output, just as much as their location. Technical
guidelines recommend that panels be mounted facing south for maximum exposure - the sun moves from east to
You also need to know a thing or two about solar panel voltages. Generally, there are three voltage ratings for
solar panels: nominal voltage, maximum power voltage (vmp) and open circuit voltage (voc).
Your goal of installing a solar system,
together with the size of your budget, will determine the amount of power you can achieve. Most people’s motivation
is to reduce on energy bills, as well as helping to conserve the planet.
Other technical jargon is best evaluated by a certified solar installer.