Solar panels are an energy saving home power solution that can help dramatically reduce both your power bill and your carbon footprint. Installing them is relatively simple and although their one-time installation cost may be high, long term prices for these panels are remarkably reasonable. Many commercial and residential dwellings use solar panels as part of their energy plan and use is only growing in popularity. This applies particularly to areas of the world where at least 6 hours of peak sunshine are available on a daily basis for large parts of the year.
However, even in less sun soaked places, panels can be installed and will still help reduce your power bill to some extent.
That said; let’s look over some important factors that you need to consider before installing a solar panel system in your own home or business. This is a fairly big decision and you need to have at least your basic facts straight if you want to go ahead with it.
1. BASIC CONSIDERATIONS
As a first step towards setting up your own solar power system, you will need to calculate your approximate energy requirements and how much of that you can expect to cover with a solar array of whatever size you can afford. Your monthly and annual energy consumption can be easily found just by looking at your monthly electrical bills over a range of several months and calculating an average annual consumption.
If your energy bills are particularly high, then you might also consider ways in which you can lower them to some extent by cutting back on using electrical lighting unnecessarily, shutting off certain appliances and maybe buying less energy intensive home appliances. You may also consult a professional electrician on how you can optimise your electrical wiring and lighting locations at home to reduce your overall electricity consumption.
With your energy consumption calculated, you need to know how much peak sunlight you can expect for your particular region. This is going to vary greatly depending on where you live but generally speaking you should be able to count on at least a few hours of peak sunlight per day for half the year. Furthermore, to improve this, your panels should be installed on a southward facing surface for maximal sun exposure.
The average American home uses about 14,000 watt hours per day of electricity. You’ll want to cover as much of this as possible with your panel array.
2. HOW MUCH FOR HOW MUCH ENERGY?
So, given that the average home uses about 14,000 watt hours per 24 hour day in powering its main electrical and electronic devices (except the heating and cooking appliances), how much solar panel coverage will you need to almost completely meet the needs of your power consumption?
Well, modern PV (photo voltaic) cells generate about 70 miliwatts per square inch; this means that if you can get 4 hours of usable sunlight per day, you’d be receiving about 280 miliwatt hours per inch per day. With these quantities, you’d need to install at least 51,000 square inches of solar paneling; this amounts to 354 square feet of panels. These will provide you with an estimated 14,000 watt hours during their peak operating times under perfect conditions. However, since you won’t normally get perfect conditions and because the sun only shines for a fraction of each day, actual energy savings from such an array may be somewhat less than complete.
Nonetheless, these 354 square feet (assuming you live in a typical middle class home) will still drastically reduce your annual power bill by as much as 90%.
3. EQUIPMENT REQUIREMENTS
Solar energy systems for homes don’t just consist of a series of glass panels. These are the most visible part of the whole arrangement, but hardly the only one. In addition to the numerous photo voltaic cells or modules, you will also have to install two other principal components. These are the electricity inverter unit, which turns the solar arrays DC current into the AC current that powers your home, and a battery cell unit, which can store extra energy for when there is no solar power coming to the PV cells in your yard or on your roof.
Certain modern PV solar panels actually have their own built-in micro inverters attached to each one of the individual cells. These are beneficial because they allow you to grow your solar array however you please without having to replace inverters to fit expanding or shrinking size requirements. They also allow for easier installation and lose less energy absorption ability under conditions of partial shade.
The most important question of all to the budget conscious green thinking homeowner; cost is a big reason why solar power isn’t more common in places where it’s not actually necessary. Even though prices have steadily been dropping as the home based solar energy market expands, PV arrays are by no means cheap even now.
An array such as our example above will probably cost you a minimum of $16,000 for the panels alone and another twice that for the inverter and battery storage system. Furthermore, the battery does have to be replaced every few years, adding to your costs. Micro-inverter based PV cells are going to save you some expense by removing the cost of a single inverter, but the individual cells are more expensive than normal PV modules.
A key cost reduction factor will be in the energy reduction measures you take. This means that before you even install your system, you should have switched to energy saving appliances, reduced the use of unnecessary lighting and decreased the number of unneeded electronics in your home. These cutbacks will allow you to reduce the size of your power bill before you even start with Solar panel installation.
5. RETURN ON INVESTMENT
So, assuming you decide to set up a solar array of at least 354 square feet and manage to reduce your annual grid based power consumption by at least 90%, how long will it take you to earn back the investment? Well, let’s assume your overall installation costs amount to a total of $33,000 to $40,000 dollars for an array of 354 square feet or more. With such an installation you reduce an average annual power bill of $1500 by 90% and are left with an annual savings of $1350. You might even manage to attain complete electrical self-sufficiency, but given the realities of weather, electrical inefficiency and other factors, this is unlikely.
With $1350 saved each year, your $33,000 investment (at the lower end of the cost scale) will be able to completely pay for itself within a little over 20 years.
However, there are a few other factors that can shorten your ROI time rapidly. First of all, there is a federal tax credit available to homeowners that cover 30% of your solar array installation costs. In addition to this, there may be a number of annual or one time state tax and utility credits that you can take advantage of in your particular state. If you live in another country, similar programs may apply for your local jurisdiction and any of them will help shorten your ROI.
Finally, you should also bear in mind the inflating cost of grid based electricity, and this is rising at an annual rate of 5% in many places. What this means is that the amount you don’t pay to the utility company each year will more than likely grow, shortening the amount of time it takes you to pay for your initial solar array installation.