Planning a PV System

 Photovoltaic (PV) Solar Systems convert sunlight directly to electricity.  They work whenever the sun is shining and work best when the sunlight is more intense and the solar panels are placed so that they get maximum sun exposure.  They are a zero-emission renewable energy source and allow you to make electricity without pollution.

The standard components of a PV solar system are:

  • Solar Panels made up of photovoltaic (PV) cells that convert sunlight into direct current (DC) power, and are usually installed on the roof
  • Inverter to convert DC power into the alternating current (AC) power that is typically used to power your home
  • Electrical Panel (breaker box) to receive the AC power from the inverter
  • Utility Meter to continually measure your electrical supply
  • Balance of System (BOS), the support structure for solar panels, wiring etc.  Note that BOS and labor for installation can be a costly component of a PV system.

The optional components of a PV solar system are:

  • Attachment to a Utility Grid to supply you with electricity when your own supply does not meet your needs.
  • Battery Storage to provide power to your home in the event of a utility power outage.

Below we have put together the basic information you need to know to determine whether or not solar is a good option to heat your home. However, even if your property is not sunny enough for solar panels, there are still ways for you to support our country’s transition to renewable energy sources.  Click here to learn about renewable energy certificates.

1.  Determine if you have enough sun for solar
For a solar panel to work at its optimal level it needs clear and unobstructed access to the sun’s rays for most of the day throughout the year.  Panels that are oriented to the south get maximum exposure.  Panels are generally placed on rooftops.  If your roof does not have the proper orientation, enough space, or is shaded by trees or other structures, they can be placed on the ground.  Some creative installations mount panels  to create covered parking or provide shade as window awnings.

2.  Figure out how large a system you need
Determine what portion of your energy needs you want a PV system to meet.  Start by figuring out how much electricity you use now.  Add up the kilowatt-hours (kWh) of the electricity you’ve used in the past year.  Make sure that you record the actual kWh used and don’t just multiply one month’s usage by 12 because usage can vary widely over the course of the year.  Note:  If you do not have your electricity billing statements, your utility company should be able to supply kWh information.

The total number of solar kWh that you need to generate for a year will determine the number of solar panels you will need.

A chart on page 7 of the Solar Consumer Guide published by the U.S. Department of Energy gives you an estimate of the number of square feet needed for different sized systems.  This consumer guide has a lot of helpful information.

3.  Determine if your roof can accommodate the system you need
PV solar panels can be installed on any type of roof, but roofs with composition shingles are the easiest and those with slate the hardest.  If your roof needs to be replaced in the near future, it can be cost effective to do it before the PV installation to avoid the extra cost of removing and reinstalling it when the roof is redone.   Another option that is now becoming cost competitive is to buy solar shingles that serve the dual purpose of solar panels and roofing shingles in one product.  Click here to read more about solar shingles.

4.  Decide if you want a stand-alone system or one connected to the electricity grid
A big question that you will need to answer is whether you want to be connected to the electricity grid or if you want a stand-alone system.
If you are connected to the grid, all of the power that your solar panels produce is fed back into the grid and the electric company supplies you with your power. This is called net metering.  The electric company keeps track of how much electricity you generate and how much you use.  If you use less than what you generate, they generally will give you a credit.   The Database of State Incentives for Renewables and Efficiency (DSIRE) explains the rules on net metering in your area, including how much you get paid for generating excess power.  If you use more than what you generate, the utility charges you for the excess. Grid connected systems have the advantage of more efficient utilization because there is no storage loss.  However if there is a power outage, you are out too.

If you have a stand-alone system, you only have access to the energy that you produce.  Since solar panels only create electricity when the sun is out, you must install batteries to be able to use energy when the sun doesn’t shine.  However, if the grid goes out, your power stays on as long as your batteries stay charged.

You can also install a battery system to provide backup in systems connected to the grid. When the grid system is functioning properly your home will use the power generated from your solar panels or pull electricity from the grid.  But when there is a grid blackout the system can switch to “off-grid mode” which allows your home to be powered by your batteries, and your batteries to be recharged by your solar panels.

5.  Understand your financing options
The three most commons ways to finance solar in your home are:

Direct Purchase – buying the system outright.  This is the simplest and most financially beneficial way to get solar because the buyer can take advantage of federal, state and local incentives which can amount to up to 30% of the purchase price.  Check the U.S. Department of Energy’s DSIRE – Database of State Incentives for Renewables & Efficiency database to find out the current rebates and incentives in your area.  The best way to finance a PV system for your home is through a mortgage loan.   You may also be eligible for the pilot PowerSaver Loan Program that allows homeowners to borrow up to $25,000 for terms as long as 20 years to make energy improvements in their home.

Power Purchase Agreement (PPA)a PPA is a zero-down financing option.  The solar system is owned, operated, and maintained by the supplier and their financing partners.  The advantages are that the buyer does not need to put any money down, and the solar electricity is sold to the buyer at a discounted, locked rate (the PPA price).  The downside is that the supplier, not the purchaser gets any rebates and incentives that are available.

Solar Lease - like a PPA, a solar lease does not require that the buyer put any money down, but unlike a PPA the solar electricity is NOT sold at a discounted, locked rate.  Lease terms are generally for around 20 years, but some leases can be shorter.  In most leases the purchaser has the option to buy the system at any time during the lease or at the end of the lease. The purchase price is usually predefined in the lease contract.  This works well for people who prefer to make payments over a longer term rather than make an up-front investment in solar, however like a PPA the purchaser can NOT take advantage of any rebates and incentives that are available.  When you sell your home you can usually assign a solar lease to the purchaser if they have the proper credit.

Your quote for a PV system should clearly state the maximum generating capacity of the system and an estimate of the amount of energy that the system will produce on an annual basis.   It is recommended that you ask an installer to quote your price both for direct purchase and a solar lease or PPA so that you are sure that the lease or PPA prices are not based on a higher total cost.

6.  Select a PV installer
It is possible to do a lot of the research and installation on your own, however, there are many advantages to hiring trained professionals.

There are several ways to look for a solar (PV) installer.

It is recommended that you get bids from more than one company if possible.

Attached is a list of important questions to ask prospective PV installers.