Who can install a PV system?

  Well, if it's your own home, you can!  I would not recommend it given the complexity in proper design and electrical code compliance.  Unless you live in Burlington or Barre, there are no laws in Vermont that forbid you to do so, not yet.  

  A licensed electrical contractor is certainly trained in code compliant practices and carries the proper insurance to provide the services of installing a PV system.  Given a few classes on proper design issues such as PV array orientation, angle, shading and temperature, a PV installation is no different than any other electrical installation.  Once an electrician has taken a few PV design classes, they are able to access the Vermont State Rebate Incentive for a client by simply becoming a "Provisional Solar and Wind Partner" of the "Renewable Energy Vermont" organization.  The only differences between being a Provisional Partner and a Full Partner is the number of customers one is able to enroll in the rebate program at a time.  Renewable Energy Vermont does not list Provisional Partners on their website, only Full Partners.  If you contact a licensed electrician concerning a new PV installation, simply ask if they are Provisional Partners of REV to know that they will be able to access the Vermont Rebate Incentive on your behalf. 

  Another option is to hire a contractor who is a "Full Solar and Wind Partner" of Renewable Energy Vermont.  All of these companies have access to the Vermont State Rebate Incentive, are properly insured, and have the credentials to design and install PV systems.  However, very few Full Partners of Renewable Energy Vermont are licensed electricians.  Therefore, if you are looking for a company who can address electrical wiring beyond that required for the PV system, you will need to hire a licensed electrician. 

  A third option is to hire a nationally recognized Certified Solar Electric Installer in your area.  The North American Board of Certified Energy Practitioners awards professional "NABCEP" certification to installers who have met a high standard of prerequisites of related experience and/or education and have passed a 4-hour exam.  There are approximately 520 NABCEP Certified Solar Electric Installers in the country.  In VT, there are only 17 certified installers.   A complete list of NABCEP Certified Installers can be found at www.nabcep.org.

    

Estimating the installed cost of a PV system

  How much does one cost? A question that I am asked quite often.  Well, it depends on a lot of factors that must be considered.  Where would you like the panels to be placed?  How much electricity do you want to produce?  Would you like to have a back-up power supply for use during utility grid failures?  Is your home connected to the utility grid?  Are you interested in applying for state financial incentives?  To name a few.

  The price tag on a PV system changes constantly.  Many of the materials, such as solar panels, are purchased and shipped from far away places.  Metals and plastics are a large part of PV system components, which fluctuate in cost as the price of oil is constantly changing.  State and Federal rebates are constantly under discussion and subject to change.

  So, despite all of these variables that effect the cost of a PV system, I have devised a very simple equation to estimate a "ballpark" installed price of a PV system.  If the desired system is one that requires short distances between components and presents no significant installation difficulties, use the lower end of the scale.  If not, use the higher end of the scale.

  The formula is as follows:

Before Rebates - Grid-tie without battery back-up = $6-10/watt

                         Grid-tie with battery back-up = $12-14/watt

After Rebates - Grid-tie without battery back-up = $4 - 6/watt

                       Grid-tie with battery back-up = $7 - 9/watt

 

  What does this mean?  Well, a PV system is usually designed to meet the electrical demand of a certain percentage of a house.  This is usually between 25% and 50%.  An average home uses about 8,000 kW-hrs of electricity per year.  25% of this consumption is 2,000 kW-hrs electricity per year.  A 2,000 watt PV system in Vermont that is facing within 10 degrees of True South, tilted between 30 and 60 degrees, and has minimal shading will produce roughly 2,000 kW-hrs of electricity per year.  Notice the similar numbers.  Let's pretend this is a Grid-tie system with batteries, appears to present no significant installation difficulties and is eligible for state and federal rebates.  I will then multiply: 2,000 watts x $7= $14,000 estimate installed cost of the system after rebates.  On the other hand, if this same size system did not incorporate battery storage into the design, I would multiply: 2,000 x $3 = $6,000 minimum estimate after rebates.

  However, every application is different.  These formulas will simply give you an idea of the potential costs of various types of PV systems.   

Payback - The Million Dollar Question!

  If only we new for certain how long it takes for a PV system to produce enough energy to pay for its investment cost.  Some say 30 - 40 years, some say 10 years.  I was recently asked by an Electrical Inspector if the payback has come down to 200 years yet!  When I told him that it takes about 18 years given the minimum 10% yearly increase in rates as warned by our utility companies, his only response was that the sysem would likely be “burned up by then”.  If that were a concern, why are solar panels sold with warranties of 20 to 25 years?  Sure, other expensive components have only 5 or 10 year warranties, but they are usually better protected from the weather.  The entire electrical service to a home comes with no warranty whatsoever.  How long do you expect that to last?

  I am reminded of an off-grid PV system that I dismantled last year only to build a much larger system in its place.  There was nothing wrong with the existing system, the homeowner smply wanted to invest in something much larger for the home and move the existing system to another building on the property.  This system had been in operation for 34 years already!  Curious of how the panels were holding up after so many years of operation, along with the fact that they looked a bit weathered, I dug out my metering equipment to test the output of the panel in full Sun.  To my surprise, the panels are still operating at the output that they were rated for on the day they were first installed.  Amazing!  

  Other “wildcard” factors to consider are the state’s ever increasing demand for more electricity, expesive infrastructure issues that arise from the increased demand, and the uncertain price tag on electricity from Hydro-Quebec and Vermont Yankee in a few years as their present contracts expire.  We presently purchase more than 30% of our electricity from Vermont Yankee, whose contract expires in 2012.  We also purchase more than 30% of our electricity from Hydro-Quebec, whose contract expires in 2015.   Given that Vermont has some of the lowest electric rates in New England, I’m a little concerned about where these rates will be when these contracts are hopefully renewed.  

  So, how long does it take for a PV system to pay for itself?  We are all guessing.  One thing for sure, regardless of how long, it could very well be the only product that you can buy that does actually pay you back!