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A Non-Technical Introduction to Solar My electric bill is too high, will solar lower it? How do I know how much electricity I use? How much solar do I need for my 2500 square foot home? Can I sell power back to the utility grid? Return to Main FAQ Page A Non-Technical Introduction to Solar Major Components: There are four major components to solar electric systems; Solar Panels, Charge Controllers, Batteries and Inverters. All of these components are necessary to have a functioning Solar Electric (PV) system. The solar panel is the basic building block of the system. This is your battery charger. If you have several solar modules wired together you have created a solar array. The size of the solar array determines the amount of power or energy that will be produced. Your location is also a factor in the amount of energy produced. If you live in Florida, Southern California, or Texas you will produce more than if you live in Oregon, Maine or Maryland. In general the closer to the equator you live your system will produce a larger amount of energy. Charge controllers come in many different sizes and types. They all basically do the same thing. The charge controller prevents the solar panel or array from overcharging your battery. Batteries are the energy storage for your system. Without batteries there is no way to store the energy your solar panels produce during the day. Typically loads receive their power from batteries instead of directly from the output of a solar panel. A solar panel produces a high voltage that will damage electronics if loads are powered directly. A common application for solar panels directly powering a load is water pumping. Instead of storing energy you store water. This way you can pump during the day and have water all night. Batteries will provide you with the energy you need at night. The last major component is the Inverter. The inverter converts the DC energy stored in your batteries and turns it into the AC power you use in your home. Inverters are rated by wattage and the quality of their output. You can use a 50 watt inverter that plugs into your car 12 volt outlet to power a computer, or you could have a 4000 to 11,000 watt inverter system that powers your home. These major components can be put together in many different ways. Minor components like wire, disconnects, circuit breakers, and fuses are also needed for a complete system. Now that you know what the major components are, let me introduce you to you how these different components are used in systems. Back Stand Alone or "Cabin" Systems A Stand Alone solar system is just as it sounds. It is not connected to the utility or other types of charging sources. This type of system is used when utility power is not present and is to costly to bring in from the nearest pole. If you have a shed set off from the house, a cabin in the mountains, or a summer home by the lake that is without power this type of system can often be very cost effective. When compared to bring in the power lines the initial cost can be less. Some of the pros of this type of system are: The lack off reliance on the utility. Potential cost savings. Some of the cons of this type of system are: Even though there maybe a cost savings over running utility line, there can be a high initial cost. You have to know your loads and have the system designed correctly since you dont have utility power for backup. Back Utility Tied System This system is the newest addition to our site. The system utilizes an inverter that does not require batteries. During the day, the power generated is fed back into the utility. If you are producing more power then you are using your meter can even spin backwards. Due to the simplicity of the system, it has the lowest cost per watt. The downfall of this system is that when the utility grid fails the system will shut down. Back Battery Backup System This is a system that does not involve solar power. This system utilizing an inverter that has a built in battery charger. It will charges batteries and hold them at 100% waiting for a power outage or a brownout. Your critical loads will never see the power outage. Computers, home health equipment, and lights will continue to operate when the utility grid fails. This is a system that is great for areas where power is lost for short periods of time. The limit on this system is the amount of battery capacity that you have. The larger the batteries the longer your run time will be. Back Utility Tied Battery Backup System with Solar This system operates on the same principal as the Battery Backup System. The difference is the addition of solar. The solar is used to charge your battery bank. When the batteries are full the excess power is fed back into the grid. In the event of an outage, your critical loads are powered by the system, and the solar panels continue to charge the batteries. The benefit of this system is that you have the ability to sell power back and have the peace of mind that your critical loads will continue to operate. The drawback is the cost per watt is higher then a Utility Tied System. Back My Electric Bill is too High, Will Solar Lower it? Yes. A solar system on your home will lower your electric bill. Unfortunately the initial layout of funds to purchase the system can be high. If you look at the cost per kilowatt hour for a solar system over its life it can be as low as $0.11 per kilowatt hour. If your goal is to save money over the life of the system and you are paying the power company more then $0.11 per kilowatt hour a solar system makes sense. In California rates are as high as $0.21 per kilowatt hour. Rates this high allow some solar systems to pay for themselves in 5 years. If you are paying less then $0.11 per kilowatt hour solar may not be for you from a cost savings stand point. A kilowatt hour of Solar will cost more than a kilowatt hour of utility electricity. The best thing to do, if you are looking to lower your electric bill is to cut down on the amount of power that you use. This may not mean you have to change your lifestyle and live like a hermit, in the dark. It means you just have to change the way your home uses electricity. An energy efficient home, that uses energy efficient appliances, will cut down your electric bill. The cost of adding energy efficient appliances to cut your usage by 100 kilowatts per month, is less than buying enough solar equipment to generate 100 kilowatts per month. So remember living efficiently does not always mean living differently. If your home is designed to be energy efficient then adding solar will reduce your bill. Since you bill is smaller to start with a little solar will mean a lot. Back How do I Know How Much Electricity I Use? Using this chart you can estimate how much power you use. The wattage for most appliances is listed on them. Just take the number of hours you use each item in a day and fill in the chart. Multiply the total watt-hours a day by 30 and you will know your estimated monthly usage.
Back How much solar do I need for my 2500 square foot home? The amount of solar you need to power your home is not dependent on the size of your home. The amount of solar depends on the amount of power you use in your home. Look at your monthly bill from the utility company. It will list the total amount of power (kWh) you used in the last billing cycle. Divide this by the number of days in your last billing cycle. This will tell you how much power you use each day (kWh). Back Can I sell power back to the utility grid? Yes, with the correct inverter you can safely sell power back to the utility grid. The real question is can I sell power back to the utility company. Most states have net metering bills that basically say the utility company will have to buy the power back from you at the same rate you buy power from them. The states that don't have net metering bills typically only pay the wholesale cost of the power, about 1-3 cents. Until uniform codes have been adopted by all utilities it is best that you first check with your utility. Each utility has different interconnection standards that have to be meet before they will allow you to sell power back to the utility grid. The unfortunate thing about these different interconnection requirements is that modern inverters have all of the safety equipment built into them as standard components. So some of the equipment a utility company may ask you to add is already inside the inverter. Many thanks to Mr. Solar for use of this material! Back Home | Product Tour | Hot! | System Design & Install | Financing! Photos | Directions | Store Hours | FAQ's | Links | Zap Scooter! Contact Us | Site Map | Search Our Site Central New England Solar Store 809 Southbridge Street Routes 12 & 20 Auburn, MA 01501 508-832-4344 We have earned the Solar Energy International Solar PV Design Certificate! 
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