The question is why are you interested in using solar or wind energy? Is it because you need some back-up electricity for when the utility grid is unavailable? Or is it because you want to spend less money per month on electricity?
Many of the folks who visit our site are interested in installing a solar or wind electric system for their home but they do not know where to begin. Although to a certain degree each situation is different there are a few basic things that we will need to know to get you started.
A Little Homework is Required
Solar electric panels (PV) and wind generators create electricity. If we are to help you size a system for your home we need to know how much electricity you use each month. If you are currently buying electricity from the utility company that information is available on your electric bill. If you are looking into a system for your RV or cabin where there are no electric bills to refer to then please go through the process of filling out the load calculation sheet in our Alt E University. Filling out this sheet requires two pieces of information - how many watts each appliance that you want to run uses and how many hours it operates in a day. Without knowing how much electricity you use we will not be able to give you an accurate system quote.
Yes, the math for figuring all this stuff out can be somewhat confusing since it involves numbers that most people never really think about. The important numbers off the appliances are listed as volts, amps or watts. Everything in the US runs of 120 or 240 volts, and if it is not a huge load like a dryer or a large power tool you can assume it uses 120 volts (or they may write it as 110 or 117 volts also - same difference just a different way of rounding the number off). Volts x amps = watts. All appliances are required to list one of these three units. If the appliance only lists amps then you are ok because you know you can multiply that by 120 to get the watts. A kilowatt is 1000 watts and the amount of time you use a specific appliance is the number of hours. For example if you run a computer that uses 150 watts for one hour you have used 150-watt hours. After you run that computer for 1000 hours you have used 150,000-watt hours or 150 kilowatt (kWh). We will also want information about your peak load or peak power consumption which is also listed on your electric bill or can be found by adding up the wattages of every single load.
The average home in the US uses 600 kWh per month and has an average of about 5 peak sun hours per day. Operating this average home will require about 80 solar panels plus batteries, inverters, fuses, wire etc... A complete solar energy system for this much energy consumption will cost between $50,000 and $70,000 - but don't be discouraged.
If you use as much as the average home or even more the first step is to reduce your electricity consumption. This does not mean "freezing in the dark". It means taking advantage of new, efficient technologies and being smart about how and when you use power. You can replace your old refrigerator, freezer, water heater, washing machine (or anything else that is more than 5 years old) for newer, more efficient models. Change all your light bulbs to compact fluorescents. Use a few swamp coolers to cool your house instead of an air conditioner. Replace large electric appliances like water heaters, dryers, and stoves for propane models. Of course using propane will still cost you but since propane is more efficient for heating, you will pay less and be able to use a smaller solar system. The big no-no's for a renewable energy system all revolve around creating or removing heat - regular household heat, water heat and air conditioners.
Easing Into Renewable Energy
It is not necessary to do a complete system all at once. You can just pull a few circuits off the main circuit breaker panel and just run the loads on those circuits off solar. If the utility power (or grid) goes out in your area a lot then you want to choose these loads based on your priority loads - what must be on even if the grid is down. Or you can do a utility intertie system that will feed some solar generated power back onto the utility lines turning your meter backwards and off-setting power that you would otherwise buy from the utility. This is less expensive than an off-grid system since there are no storage batteries and because it is not necessary to cover your entire load.
If you are interested in a wind electric system we will need all the same information about your consumption and we will also need some information about the average wind speed in your area. A quick way to get this information is to call your local weather bureau or airport. You can also visit the website of the National Renewable Energy Lab and find your city in their Wind Energy Resource Atlas. Alternatively, you can supply the exact name of your town and the name of the closest big city and we can find average wind speed information. Cost-wise a wind system to operate the average home in the US will cost around $30,000 - $50,000 depending on the wind resource and whether it is battery based or not, so it is a bit cheaper than solar.
Selling Power to the Utility Company
Selling power back to the utility makes things more complicated. Selling power back means that you are purposely installing more solar or wind capacity than you need and hoping that the utilities will buy the excess power back. The utilities are legally required to buy it back but at what is called "avoided cost" which is generally 1 - 3 cents per kilowatt hour. Although some utilities in some states will buy it back at the same rate that you buy it from them (this is called net billing) these utilities are not the majority. This is different from offsetting power with a utility intertie inverter.
Most utilities do have what is called "net metering" which means that a solar or wind system installed on your property can be used to generate electricity and turn the utility meter backward. This allows you to offset power that you would otherwise buy from the utility. As long as you only generate the amount of power you traditionally use on a monthly basis and don't generate a lot extra to sell back you will fit into the net-metering category. These systems can be set-up to charge batteries for back-up power systems in addition to turning the utility meter backwards but it adds some complexity and increases cost. Be prepared to make contact with your utility to see what their rules are. If you are pursuing a wind electric system, be prepared to contact the county or township to make sure that there are no restrictions against tall towers. Some utilities or townships are very easy to deal with and the negotiations go off without a hitch. In some cases, they make it very difficult to even get the information about what you can do.
If you live in sunny Florida or the windy Midwest you may be able to install a renewable energy system for less than these average numbers indicate. Maybe you are just powering a cabin or an RV which use very little power generally. Better yet, maybe you are just building your home and you will have the opportunity to make it well insulated, efficient, oriented properly towards the south to take advantage of passive solar heating and daylighting. Doing all of these things will dramatically reduce the amount of energy you use thereby reducing the cost of a renewable energy system.
The question is why are you interested in using solar or wind energy? Is it because you need some back-up electricity for when the utility grid is unavailable? Or is it because you want to spend less money per month on electricity? In either case it is possible to install a smaller and less expensive system that will supply a portion of your electricity needs.
If it is because you want to spend less money per month then you may want to start by hiring a solar person or energy efficiency person in you area to come into your home and suggest ways of reducing your electricity consumption. These ways may be as easy as changing all your light bulbs to compact fluorescent bulbs or as difficult as changing out your old electric water heater for a propane or natural gas model. Any of these things will save money to different degrees. Once your home is as efficient as it can be, then you may want to consider installing a wind generator for "utility intertie". This system may not cover your entire electricity bill and can be as large or small as your budget allows with certain limitations on the size of the utility intertie inverters you have to choose from. This type of system is subject to acceptance from your local utility so you may want to contact them to see what their terms are. This type of system has very limited battery storage capacity in order to keep the price down so it is not typically thought of as offering back-up power.
Free Money for Your System
Many states offer incentive programs for folks to buy renewable energy programs to offset the costs of purchasing and installing systems. The incentives range widely. Many folks are completely unaware of the programs that are offered in their states, and miss out on a large opportunity to offset the costs of their system. Want to find out what incentives your state offers? The University of North Carolina offers a great, comprehensive database of state incentives. Click here to pop up a window with their site.
If you are interested in wind energy to provide back up power during utility outages in your area we still suggest doing whatever you can to increase the efficiency of your home first. A back-up power system like this is generally used to provide power for "priority loads " when the utility grid is unavailable. Every one has their own priority loads but they generally include the refrigerator, water pump, heater blower and some lights for example. The wind generator and battery bank are sized to power these priority loads for a period of a couple of days or how ever long you typically are without power. This system can be set up so that it powers the priority loads all the time or so that it only comes on when the grid goes down. This system also can be as small or large as your budget allows. The smaller the budget the more selective you will have to be about which loads to run.
If you want to pursue a back-up power system the next step is for you to identify your priority loads, determine the electricity draw and hours of run time for each one. Further information on how to do a load calculation is located in our University section. If you want to pursue a utility intertie system we must have some idea of your budget or what portion of your electric bill you would like to try to offset.