Are You Ready for a Solar Photovoltaic System?

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Thinking about installing solar in your NJ home or business? Here's what to expect along the way, an explanation of some key terms, and a planning time-line (at the bottom of this post) to help ensure the entire process goes smoothly. There are also links to information on New Jersey solar incentives, rebates, legal and tax considerations.

In full disclosure, we are solar contractors in New Jersey. From our experience, we have written this post as a handy guide for New Jersey home and business owners who are thinking about switching to solar energy for electric, hot water, or both. We are not trying to sell specific products or push specific services/installation types. There are a number of important things to consider before making the jump to solar. We hope this overview will help you better understand them all.

Most of our discussion is relevant no matter where you live, however if your climate is significantly different than the climate in New Jersey, you may have additional, or different, considerations we don't cover here.

Gather Electrical Bills

To a large extent, the size of your Solar PV system will be determined by your present use of electricity. You should gather one year’s worth of electrical bills. Copies can be obtained from your utility company and are often available online. Your Solar contractor will use this information to determine how many panels you will need, what size panels you will need and what kind, number and size inverters you will need. Your electrical usage information is also useful in determining your payback period- how long it will take you to recoup your investment.

Solar Site Survey

To begin, your contractor will use ‘Google Earth’ or a similar satellite mapping service to initially check the suitability of your location. He/She will look to see if your roof can be observed from the satellite.

The contractor will then get on your roof, if it is accessible, and take critical measurements. They will draw a roof plan, locating all existing roof penetrations such as plumbing vents, exhaust, chimneys and determine the general condition of your roof and its age. If your roofing material is at or near the end of its useful life cycle, it may make sense to repair/replace it prior to the installation of a roof mounted Solar panel system.

Next, they will use an inclinometer to check the pitch of the roof. This is important for two reasons. First, the inclination of the roof relative to the latitude will affect the amount of sun the panels receive and therefore how much electricity they produce. Second, a roof with a severe pitch will require additional safety equipment, such as roof harnesses and roof ladders. This can affect the cost of the installation.

Then your contractor will check out your existing electrical service and main panel. Your new Solar PV system must properly tie into your panel. An older panel might require replacement. Your contractor will also examine your attic. A Solar PV system puts additional weight on the roof, and the roof must be able to handle this extra load. The roof construction, along with attic floor construction will determine the load bearing capabilities of your roof. (for more on this - see bulleted list, below)

The contractor should also take a compass azimuth reading of your roof. It must be determined where and when the sun will shine on your roof. A northern facing roof will not get direct sun and cannot be used. Southerly facing roofs are ideal, but other westerly and easterly directions will also work.

The contractor will use a special instrument called a Solar Eye. This is a combination fish eye camera and computer. Your geographical location is programmed into the device, along with roof tilt and compass direction. This device will locate any source of shade that might hit your roof, any time of day, any day of the year. It determines what your “insolation” rate will be. Perfect is of course 100%. Less that 70% might mean alteration of the panel mounting pattern to avoid shade. In northern New Jersey, a good roof averages 4.5 hours of useable sun light per day.

When all the parameters are fully known, it becomes a matter of simple geometry. How the largest number of panels be installed on the given roof surface. Ideally, we like to use the largest wattage panels we can. The installed cost per watt goes down as the size of the panel goes up. Panels come in outputs from about 75 watts to over 200 watts.

The final technical calculation required is the selection of the inverter. Your Solar panels convert the sun’s energy into direct current electricity. Your house runs on alternating current. The inverter does the job of changing direct current into useful alternating current. The panels are wired together in patterns called “strings” and each “string” is wired into the inverter. The inverter then sends alternating current into your main electrical service panel, where it will provide electrical power to your whole house.

With all this information, the contractor will provide you with a preliminary proposal.

Permits and Your Utility Company

Once you agree to a proposal, your contractor will begin to deal with outside agencies… utilities and municipal building departments.

You must apply to your electric utility for special electrical “net metering”. Remember, when you generate MORE electricity than you use at a given moment, the excess power goes back out to the electrical grid and your meter runs ‘backwards’, earning you a credit towards power you will take from the grid. The utility company will install a special “net metering” meter to accomplish this. The forms for obtaining utility approval are generally available online. Your contractor will obtain and file them for you.

When your contract has been completed and signed, either you or your contractor will apply for your NJ State rebate. The requirements and forms for the rebates are available online.

You will also need to open an account with the state of New Jersey for SRECs – Solar Renewable Energy Certificates. SRECS represent the power your Solar system produces, whether used by your home or sent out to the grid. You will earn approximately 1.1 SRECS per year for each KW of installed solar capacity you have. The SRECs have an average value in New Jersey of $ 527.00 as of July 2009.

We have found the most time consuming aspect of the project can be obtaining your permit from your local building department. Most building departments have little or no experience with Solar installations. Typically, here is what they are likely to require:

• Factory specifications for your Solar panels and your inverter.
• A complete wiring schematic of your installation, showing locations of panels, inverter, disconnect switches, strings and wiring sizing.
• Installation instructions and specifications of the roof mounting racks, specifically showing how the panels are to be mounted and how roof leaks are avoided.
• Roof loading specifications: The building department wants to make sure that your roof will be able to support the added weight of the panels you will be installing. The average system adds about 3 pounds per square foot to your roof. Many roofs can handle this easily. Some, however cannot. You will be required to engage the services of a professional licensed engineer to make that determination. He will provide documentation to the building department attesting to the roof load capacity. Should your roof loading capacity be insufficient to handle your Solar panel system, he will recommend the required construction upgrades.

At this point, all paper work is complete and permits and approvals are in hand. Your equipment is ordered from the Solar Vendor(s) by your contractor. Equipment delivery is usually within 2-4 weeks. Your installation will take anywhere from several days to 2 weeks, depending on the nature of your home and the system design. The municipal, utility and state inspections are arranged, usually with in another week or so and then… your system is turned on.

Congratulations. You've gone Solar! 

New Jersey Residents...Visit our Solar Page for more information

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