Becoming less dependent on municipalities is a worthy endeavor and is the dream of some people. However, given recent events where utilities have been disrupted for days and even weeks becoming independent is a matter of survival in some cases.
Having a solar system connected to the grid means that when the grid goes down so would the inverter in most cases. This means you would need a backup system installed for grid connected systems so you can operate off the system when the grid does go down. Once the grid fails, you can produce electricity but you cannot feed the surplus back to the grid. There would not be any exporting of energy.
Having an off grid system means you have a battery bank capable of supplying energy to the entire home when the solar system is not generating energy. The surplus can be exported to the battery bank and then used at night or on cloudy days. However, to go completely off grid you would have to have enough panels to supply the entire home from the onset, which is costly.
There are many things to keep in mind when considering solar panels. Most would agree that the pluses outweigh the negatives however.
The negatives would be the initial cost, maintenance and the fact that the system does not last forever. In some areas of the country special permits are required to install solar panels and the fact the panels cover most of a home’s roof can be problematic if firefighters have to get on to the roof to fight a house fire.
The panels can be damaged or vandalized and they in most cases cannot be taken with you if you purchase a new home or have to evacuate.
What Is Solar Power
The method of generating electrical power by solar radiation is called photovoltaic (PV). Electricity is generated when sunlight strikes the cells of a solar panel, which are filled with monocrystalline silicone. The resulting reaction when sunlight strikes the silicone-filled cells creates electricity. Direct Current (DC) is produced by each cell that then must be converted to Alternating Current (AC) for the average home. Electricity is produced whenever sunlight is striking the panels.
One of the things that must be considered is the reason why you want solar panels. Do you want to supplement or offset your current electrical usage by using solar panels to operate some of your higher consuming appliances such as heating and air conditioning units or hot water tanks?
On the other hand, you may want some panels installed to operate certain appliances during a power outage, appliances such as refrigeration, heating, and cooling systems. Then there are those that want to go completely off grid. The reasons why you want a solar system have much to do with the type of system and number of panels needed, which ultimately affects the cost of your solar system.
Calculating Number of Panels
The following formulas are for informational purposes and are approximations only. The real numbers would be your actual usage and other factors. Once you have determined your usage you simply substitute your figures to get an estimate on the number of panels needed based on your needs.
Before getting started, you will need to determine the number of kilowatt-hours you use every year. This may be on your bill or you can contact the power company for this information.
In 2012, the average annual electricity consumption for a U.S. residential utility customer was 10,837 kWh. Louisiana had the highest annual consumption at 15,046 kWh and Maine the lowest at 6,367 kWh (Administration, 2012).
Use the provided averages keeping in mind these are only averages and will not necessarily reflect your situation. Take the figure 10,837 and divide by 365 days in the year, so 10,837/365 = 29.69 kWh per day. Then you must break the kilowatts down into watts used by multiplying by 1,000 so, 29.69*1000 = 29,690 watts per day.
After inserting your own figures and arriving at a daily usage, you need to determine number of peak sunlight hours your area receives every day. Then take the watts used daily and divide by number of peak hours of sunlight daily. The average peak sunlight averages from 3.0-6.5 in the United States. Use five hours for argument sake so take 29,690/5 and you get 5,938. This figure is the number of watts your solar system must generate during peak sunlight hours daily to supply the entire home. Solar panels are rated on the number of watts they produce during a peak hour of sunlight.
If you want to operate certain appliances only, you would have to determine what the total wattage usage would be and install enough panels based on the formula to operate the appliances.
To determine number of peak sunlight hours daily in your area visit:
To go completely off grid you would need a backup system to supply power on cloudy days and at night and this means, a battery bank must be installed. Additionally the battery bank would absorb any surplus electricity generated during peak sunlight hours.
If connected to the grid the power grid absorbs the surplus and then the excess is credited back to you for use during the night and on cloudy days because you will not have a battery bank in some cases. You may even generate enough electricity to receive a check back from the power company.
It is conceivable that if you have enough panels installed you may never have another electrical bill and may receive a check every month from the power company because at this point you are selling them electricity.
Installation of solar panels while the price has come down it can still be costly. However, most states offer tax credits and rebates for installing the panels. You can save on the cost of installation by doing the work yourself if you are qualified.
Add a few panels at a time to help spread out the cost and start by operating a few appliances to help reduce your monthly bill and the savings can go toward purchasing and installing more panels.
Even a little shade can reduce the amount of electricity generated by the entire system so it is important that you accurately determine the number of peak sunlight hours daily. If your roof is heavily shaded, you can consider installing the panels on poles in areas on your property. Keep in mind however the farther away your house is from the panels’ means, more electrical cable must be used and this can increase the cost.
On average a solar panel, will last 25 years. However, a panel that is 10 years old will show a reduction in output, so it will generate less electricity than a panel that is only one year old.
Those just starting out should determine how much electricity they want to generate on their own to start with then increase over time. You can start out by generating 20 percent from solar for example and increase in increments.
Administration, U. E. (2012). Retrieved 2014, from http://www.eia.gov/tools/faqs/faq.cfm?id=97&t=3
Bluejay, M. (2013). Retrieved 2014, from http://michaelbluejay.com/electricity/solar.html
Technica, C. (2014). Retrieved 2014, from http://cleantechnica.com/2011/12/13/how-much-do-i-need-an-answer-to-the-most-common-question-in-solar-power/#0Wc3dP8fIQxvFLBc.99