This is Part 3 of my Being Green series and Part 2 of my photo voltaic articles.  This article will cover the steps for the installation of a photo voltaic (PV) system at a residential location.  One would think the process is fairly simple and possibly a homeowner could do this himself/herself.  After going through the process myself, I would not advise doing it yourself.  The process is quite involved and there are many areas where you could really cause some big problems to your home.  One of the biggest pitfalls is compromising your roof and causing leaks that could damage your house and contents.  Also because the PV system is usually placed on one’s roof, you could seriously hurt yourself if you fall.  So my advice is use a professional to install your PV system.

Your PV contractor creates a plan for your system by choosing the best location and number of panels to install.  Also required is connecting into your existing electrical system and working with your commercial electrical utility provider (power company) to set up your net-metering agreement.  In Hawaii, a Building Permit is required for this job and an inspection will be done before the job is complete.  Your power company will also need to approve the installation and change out your electric meter to one for net-metering.

An important step before any panels are installed is making sure that your roof is in good shape.  Once the panels are installed, you do not want to have to remove them to fix your roof.  In my case, this meant having the roof sealed with a product called HydroStop which is a thick white liquid and webbing that made the roof waterproof.  Depending on the type of roof you have, other methods maybe used.  This brings out an important point.  If you need to redo your roof, who should you get to do this?  A good roofing company of course.  It is important to make sure your PV contractor is certified in roofing and not only the PV system.  You don’t want someone messing up your roof when they are putting in your PV system.  This may cost you more initially but as the saying goes, “You get what you pay for.”  In the end, it will cost you less money as well as time.

Once your roof is ready for the installation, the first step is to install the racking system for the panels.  The PV panels are not attached directly to your roof but are secured to a metal racking system. The racking system is made up of metal rails which are elevated off of the roof by short metal stands.  The stands are secured to the roof using large screws (lag bolts) that penetrate your roof.  Care must be taken to seal all the holes (penetrations) made into your roof otherwise leaks will occur.  Carefully planning on where the stands are placed is required, in order to secure them to the home’s beams (rafters) under your roof top.  This layout is important again because you don’t want a lot of extra holes in your roof from mistakes.  Since the panels maybe exposed to strong winds, making sure they are secure is crucial.  This part of my installation took an entire day but again, it is important that this is done correctly in order to avoid problems in the future.

Next the rails are installed on the stands.  Once that is done, in my case the micro-inverters were attached to the rails (see Part 1 of my articles if you want to know what a micro-inverter is).  The micro-inverters were then connected together using special waterproof cables.  These cables are also attached to wires which were run from the roof to your main electrical breakers next to your electric power meter.  If you are getting a system with a central inverter (versus micro-inverters), the wiring is a little different.

The next step is to install PV panels.  The panels are lined up next to each other and are clamped on to the rails using special clips.  The wiring from the panels is connected to the micro-inverters or are connected in the central inverter system and routed to your home’s main electrical panel.  The wires that are run to the main electrical breaker are installed in electrical piping called conduit for protection.  Also all the panels and racking system must be grounded for protection.

Back on the ground, electrical circuit breakers and a disconnect switch are installed to connect the wires from the inverter(s) to your home’s electrical system.  This must be done so that power that is generated by the PV system can be used by you or can be routed back to your power company’s system via your electrical meter.  If your PV system is producing more electricity than your home needs, it can be shared with others customers of your power company.  When this occurs, your electric meter will run in reverse.  When you need more electricity than you are producing, then your connection to your power company will provide that electricity and this is when the meter runs in the normal forward mode.  This is how net-metering works.  The goal is that over time (a week or month), you produce the same amount of power that you consume.

The last component of the PV system that needs to be installed is the monitoring system.  This system keep track of how well the system is running and how much power is being produced.  Most systems are connected to the Internet so that you and the vendor can mange the system remotely.  The monitoring system knows if a panel or inverter is malfunctioning and can alert you that it needs to be serviced.

So after two and half days of work by the professional PV installation team, I was able to see my system turned up and producing electricity for the first time.  I had a great feeling when I saw my electric meter running in reverse.  Not only was I now saving money from paying for fossil fuel but I was harnessing the largest energy source available on our planet, the sun.  This system will benefit the future generation because it uses renewable clean energy.

I would like to repeat that the installation process is a fairly involved process which requires expertise which the average home owner does not have.  Also, you need to find a competent contractor that is certified for PV system and roofing.  The dangers of installing a PV system are real and if done incorrectly could be a nightmare that you will not soon forget.  However, done correctly, this can be a rewarding endeavor.  

I would like to thank Guy, Charles, Wayne, Les, Lyle and Edgar of Green Path Technology and Commercial Roofing (and electricians Demi, Gil and Randy) for their professionalism and information for this article and installing my home PV system.