Solar Power Generation

January 9th, 2010

If you’re thinking about changing to a home solar power generation system, you’ll need to figure out how many solar panels are necessary in order to meet your needs Even a small number of panels can make a big difference when it comes to your monthly electricity bills. If you want to go all the way off the grid, though, you’ll need to be specific about how many solar panels to use.

The first step is figuring out how much electricity you use in your home per day. This can be done by looking at your monthly electricity bills from the recent past. (In some cases, you can find these records online if needed.) You can determine using these bills the number of kilowatt-hours (kWh) of electricity you use per month. When you divide this figure by 30, you’ll get your average daily electricity usage in kWh.

You’ll also need to be aware of the insolation figures for your area. The term “insolation” refers to the amount of usable sunlight the panels will experience in a given area. Solar panels generate electricity when struck directly by sunlight. Every solar panel has its own requirements in terms of minimum intensity of sunlight in order to work. Sunlight exposure for a given surface, of course, will tend to vary over the course of a year. It even varies just over the course of one day. Every area has an average insolation value. Maps displaying insolation values can be found online. Once you’ve got the insolation value, divide your kWh usage figure from the previous step by the insolation value to find the amount of power you’ll require from your solar power system.

There’s one more variable to consider. Although the most recent systems are much more efficient than older ones, with any power system, there is always some power lost in conversion. This can be difficult to measure precisely, but it’s generally safe to use the figure of 25%, so if you multiply the figure from the previous step (kWh/insolation) by 1.25, you’ll get the amount of power (including loss) that you need. This final figure shows you how many kilowatt hours of power you’ll need your system to produce per day, with loss and insolation factored in.

Divide this figure by the output in kilowatt hours of your solar panel of choice to find out how many of these panels will be necessary in order to produce enough power for your everyday needs.

One of the first questions a homeowner faces when choosing on whether to install a home solar power system is, “How many solar panels do I need?” If you want to know the answer to this question, head on to How Many Solar Panels Do I Need?

If you want to build your own solar panel, visit Build Solar Panel. A mini course on how to make your own solar power system may also sound interesting to you. Visit Solar Power Calculator to sign-up for a 6 part mini course.