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When Should I Add aSolar Power System toMy Home?Even though solar energy offers many benefits, a rooftopsolar power system is not the first step to saving energy,money and the environment. If your home wastes energy,improving its energy-efficiency should be your firstpriority.An energy-efficient home reduces the amount of poweryou use from any source, so efficiency trumps renewableenergy in being good for the environment, conservingnonrenewable resources, helping our nation’s energysecurity and keeping more of your money for otherthings. A “high performance” home also could providemany other advantages such as greater comfort, quality,durability and indoor air quality.It usually doesn’t make good economic sense to installa rooftop solar system until your home is reasonablyenergy-efficient. Otherwise, you’re spending money toproduce electricity that you would not need if your homewere more efficient. Investing in an effective home energyupgrade typically produces a greater return on investmentand costs less than a solar power system for the samereduction in electricity use. Moreover, increasing theenergy efficiency of your home reduces the size (and cost)of the solar system needed to supply your power needs.An exception to this general rule would be when majorsolar incentives are available but will soon expire or maybe reduced. In such a case, it may be reasonable to firstinstall a solar energy system that can supply up to half ofyour annual power need so you can take advantage of theincentives while they are available. That would leave roomto still increase your home’s efficiency up to 50 percent, soyou could make the energy improvements afterward andreap the full benefits of efficiency plus solar energy.So, Before You Go Solar Learn about the most effective ways to increase yourhome’s energy efficiency in your climate atwww.energystar.gov, www.energy.gov andwww.eXtension.org. To optimize the efficiency of yourhome and get the most “bang for the buck” withoutcreating air quality or moisture problems, it can behelpful to get a customized home energy checkup, homeperformance improvement plan and quality assurancetesting by a trained home energy professional. You canfind certified home energy pros at www.resnet.us andwww.bpi.org. Find out if your local utility company offersenergy efficiency programs, home energy assessments ordiscounts or rebates for energy-saving appliances, homeimprovements or new homes.If you’re planning a new home and want to include solarpower, consider building a “zero-energy ready home”with an experienced high-performance home builder. Forreliable information on high-efficiency building systems,technologies and detailed guidance, explore the BuildingAmerica Program Solution Center at https://basc.pnnl.gov.Analyze Return on Investment(Savings and Payback)By combining energy efficiency and a home solar powersystem, you could potentially produce much or all ofthe electricity you use on an annual basis. Whether youpurchase or lease a home solar energy system, you’remaking a major long-term investment and should analyzeall costs and likely savings or payback before making adecision.Consider: Available tax credits, rebates and incentives from allavailable sources. Initial cost (equipment, installation, permit fees) ormonthly costs (loan or lease payments) for the expectedequipment life or lease term. Maintenance costs (monitoring, inspection, cleaning,landscape pruning, removal to reroof, etc.). Replacement costs of system components (inverters,batteries, etc.) with a shorter lifespan than the solarpanels. Your average and annual electricity use and cost perkilowatt-hour, both current and projected. How much electricity per year the system is expected toproduce. The rate or credit you will receive from the utilitycompany when your system produces more energy thanyou use. How the solar system is likely to affect your home’sappraised market value and how long you plan to stay inthe home. The expected productive life of the solar power systemor the length of the lease contract.It can be tricky to calculate the return on a home solarinvestment, especially if leasing or financing a system.Purchased rooftop solar payback periods can range fromseven to 20 years without incentives. Incentives shorten thetime it takes to recoup the cost and see real savings.You also may wish to consider timing for a solarinvestment. As costs of solar power systems decline,efficiencies increase and utility electricity costs rise, thepayback period gets shorter. After a solar power system isinstalled, it may be impractical to upgrade the system totake advantage of a newer, improved technology.LSU AgCenter Pub. 3363 Solar Power For Your Home: A Consumer’s Guide3

Find IncentivesA variety of incentives may be available to you that lowerthe cost or increase the return on investment for a homesolar energy system. Common incentives include incometax credits, property tax exemptions, rebate programs fromgovernment agencies or utility companies, payments orcredits based on electricity production, grants, loans, netmetering policies and others. They vary by state and cityand by whether the system is purchased or leased and theymay change or expire.Fortunately, there is an easy way to find incentives!Visit and browse the Database of State Incentivesfor Renewables and Efficiency at www.dsireusa.orgto explore summaries of renewable energy and energyefficiency financial incentives, programs and policiesavailable at the federal, state and local levels. Because newprograms are formed frequently and not all may be listed,it’s a good idea to check the database and your local utilityprovider periodically to find out what’s available to you.Likewise, many incentives may change or phase out asthe renewable energy industry grows and the technologybecomes increasingly productive.Examples from DSIREUSA.org (in 2014)1. Click on View Federal Incentives, then on ResidentialRenewable Energy Tax Credit to see information aboutthe 30 percent federal tax credit available until Dec. 31,2016. Click on your state to find available residentialincentives and programs. For example:2. If you click on Arizona, then narrow your search to seeResidential Incentives Only, in 2014, it revealed: A personal tax credit of 25 percent of cost of solarand wind devices, up to 1000. An energy equipment property tax exemption of100 percent of increased value. A solar and wind equipment sales tax exemption. Numerous utility rebate and loan programs.Several cities with green building and rebateprograms.3. If you click on Louisiana, in 2014, it revealed a varietyof state and local financial incentives, including thestate personal tax credit for solar energy systems onresidential property. Until 2018, homeowners can use a state tax credit(refunded even if in excess of taxes owed) of 50 percent of the first 25,000 spent to buy solar technologies, in addition to the 30 percent federal incometax credit. Using the state and federal tax credits, ahome system valued at 25,000 can be purchasedfor about 5000. If the solar system is leased, however, the leasingcompany receives a smaller tax credit.4LSU AgCenter Pub. 3363 Solar Power For Your Home: A Consumer’s GuideWhat Is in a HomeSolar Photovoltaic (PV)System?Solar PV BasicsThe basic unit of photovoltaic or PV, technology that converts light to energy is the solar cell. Multiple solar cellsare connected and sealed together to form a PV module.ArrayPanelCellModuleThe power-generating components of a solarphotovoltaic system.Solar panels include one or more PV modules assembledas a pre-wired unit. In most systems, several solar panelsare linked to provide the desired power capacity, typicallymeasured in kilowatts. The complete set of panels thatform the entire power-generating unit is called the PVarray. Most home PV systems are assembled as an arrayof multiple panels attached to the roof, so they are oftenreferred to as a “rooftop solar system,” even though thearray can be installed on a free-standing frame or otherstructure on the property.A PV array typically includes a mounting system attachedto the roof and one or more inverters to convert theelectricity it generates from direct current (DC, the typefrom batteries) to 120 volt alternating current (AC, thesame as the electricity delivered to your home by yourutility company). A central inverter system normally issized for the entire array.Microinverters are an alternative approach to thesingle-inverter system commonly used on homes. Eachmicroinverter operates with a single PV panel or moduleand connects to other independent units. This allows forsimple future system expansion – without the need tochange out much of the existing system – and providesimproved installation and fire safety. It also avoids thepossibility of being completely without solar power if aninverter fails and has a less expensive replacement costthan a single-inverter system.With a single or central inverter, if one panel is shaded ormalfunctions, that can greatly reduce the entire system’soutput. With microinverters, only the affected panelsreduce output while the rest of the system continues fullpower production.

The conversion of power from DC to AC by the inverterconsumes some of the solar power that has been produced.There is less energy loss when solar PV directly powersDC or “solar ready” appliances and equipment. LED bulbsand many electronics (computers, TVs, mobile phones,etc.) are powered by DC electricity, as evidenced by theAC to DC inverters commonly visible along the cord forthose devices. Any direct DC interaction between a solarPV system and its connected equipment may require additional control devices and wiring.In the future, homes may come with dual currentelectrical networks where a dedicated DC nanogridor microgrid uses solar electricity and batteriesto directly power solid state lighting, cooking,refrigeration and telecommunications alongside thetypical utility connected AC macrogrid.electricity produced is supplied to the main electrical panelof the house, offsetting the purchase of power from theutility company. Since the home is still receiving somepower and continuous power-support services from theutility, there will still be a monthly electricity bill (yet lessthan before).Additional meters may be installed or the original electricmeter replaced with a “smart” digital meter, to separatelymeasure power from the solar panels and electricity fromthe utility company. Some meters also can measure time ofuse for variable rate structures.There are several important benefits to grid-tied systemsversus off-grid systems: They are considerably less expensive, safer and requireless maintenance. There is no need for a suitable safestorage space large enough for the battery bank.Types of Home Solar Power Systems They combine solar power with the consistency ofutility generated electricity to produce enough powerto meet all needs, even when the solar system is notproducing power.The two basic types of home solar photovoltaic (PV)systems are stand-alone, also known as off-grid andutility-interactive, also known as grid-tied. In most areas, surplus energy produced when the sun isshining (in excess of your home’s use at the time) cancreate a credit on your utility bill.Off-grid or stand-alone systems are not connected to autility power grid.They include abattery bank thatis large enough topower the home atnight and duringextended periodswhen the panelsdon’t receivesunlight. This addssubstantial costBattery bank for an off-grid home solarand maintenancepower system.requirements to aPV system but can be a more cost-effective alternativeto having new utility lines extended to remote locations.Off-grid systems also can be designed to serve as a backuppower system in place of fuel burning generators.At this time, most grid-tied systems are required bybuilding codes to automatically shut down whenever thereis a grid power outage. This is a safety measure to protectpower-line workers and neighbors on the same utilitycircuit. That means your solar system does not providepower when the grid is down, contrary to what manyassume.Grid-tied or utility-interactive systems are connectedto the electric utility lines and are the most common andpractical systems for most homes at this time. The solarUtilityserviceSolar PV arrayconverts light toDC electricityMeterInverter convertsDC to ACElectrical servicepanelHybrid systems and new inverter technologies that allowthe home to use solar power during a grid power outageare becoming available. Such a system would provide avaluable backup power system during daytime. Emergency power inverters are grid-tied inverters with afeature that allows a small amount of power to be drawnto a dedicated outlet when the grid is down. The solarelectricity cannot be delivered through the building’swiring system, so it can’t power major loads but canprovide critical daytime charging of electronics andother small power needs. “Islandable” PV systems use a small battery bank,a bimodal battery inverter and sophisticated controlsthat can allow most or all of the solar system capacityto be used when the utility grid is down and the sun isshining. Smart inverters can receive and respond to grid signalsto help keep the power grid stable. Inverters that cansafely disconnect from the utility grid during a poweroutage but retain the ability to convert DC electricityinto usable AC electricity for the entire home (withoutbatteries) are in development and may soon becommercially available.Grid-tied home solar power system.LSU AgCenter Pub. 3363 Solar Power For Your Home: A Consumer’s Guide5

Bidirectional battery storage or inverted demand isan emerging alternative approach. As the technologymatures, it could provide backup power to a building (withor without a solar photovoltaic system) and contributeto some of the goals of using solar energy. Batteriesconnected to the grid and charged at low demand times(night) could reduce peak demand during the day (whengrid power is more costly). When there is a variable utilityrate structure by time of day (higher rate at peak demandtimes), a bidirectional battery storage system could providelower electricity costs for the customer, reduce peakdemand costs for the utility and help conserve energy.Net MeteringWhen a grid-tied home solar PV system produces morepower than is being used, surplus power is fed into theutility grid. Net metering is a solar incentive designed toincrease the return on your investmentin a PV system by crediting your billfor this surplus power at a predetermined rate.Net metering legislation or regulationshave been enacted by most states tojump-start renewable energy development, but policies vary by state.Net metering policies usually require electric utilities toeffectively “run the meter backwards” when an eligiblecustomer’s PV system is producing more electricity thanthe home is using. With net metering, you are billed forthe net amount of electricity you used during the billingperiod. In other words, you pay the difference between theelectricity coming from the grid and the electricity you putback in

Cost is the primary hurdle for solar power systems at every home. A solar system that can power a home is expensive. Financing may not be available or affordable or the homeowner may not qualify. Finding and evaluating financing options can be an intimidating and confusing process. Solar energy isn't continuous, since it's not available