At today’s costs solar panels can have a payback of eight years only with the “help” of tax rebates and Solar Renewable Energy Certificates, SRECs, which are available to residents of Washington DC and a few other states. Currently, SRECs in Washington DC are the most valuable in the nation, but it is an artificial market that will fall as more solar systems are installed and the price supports are decreased in the next few years. If you live in the District you can see what the cost and return of a solar system on your building’s roof top would be using the Mapdwell Project mapper. This assumes the SREC market remains viable. The solar system size used is based on the size of the roof and is effectively the maximum size solar array you could install. You of course could install a smaller array. To those of you not old enough to remember, this is the second time that solar panels have been installed on the White House. President Jimmy Carter spent $30,000 on a solar water-heating system for West Wing offices in the late 1970's that were subsequently removed by President Ronald Reagan.
As I watched the U-tube video of the White House installation I was a little envious of how smoothly it all seemed to go. This was not the case with my installation. On the back of my house is a roof mounted 7.36 KW solar array consisting of 32 Sharp 230 watt solar photovoltaic panels and 32 Enphase micro-inverters, somewhat larger than the “typical” home installation, but not much larger than what I imagine the White House installed. When I purchased my solar panels I choose the Enphase micro inverter system so the power cables running down the side of my house, albeit inside a pipe, are 120 current instead of 240 and the energy production of each individual panel can be checked on the internet. The solar array consists of panels the racks that hold them, micro inverters and wiring and plugs. My installation did not go smoothly, and surprisingly to me, maintenance has turned out to be an issue.
I check my solar panels production numbers every month when I get my power bill. I am on net metering with my power cooperative to sell my SRECs into the Washington DC SREC market where my system was grandfathered when it was closed to out of city systems. My installation web page allows me to see the current energy produced by each of my 32 panels every minute, every hour, daily, weekly, monthly and the cumulative total power output. I only spot check the solar panel midday on the day when my power bill arrives or after storms to make sure all the panels are performing optimally. The reason I chose Enphase was to be able to easily identify a problem with the system. Little did I know that barely three years after the installation I would be facing repair issues.
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| my solar array with the failed panels |
It took a while for them to come out. They looked into my system and spoke to Enphase and determined that the problem was probably the micro inverter so they ordered a new inverter from Enphase. By the time they had scheduled my repair a second inverter had failed. I was delighted when they were able to replace both inverters on the same day. According to Lighthouse Solar, they have replaced many Enphase inverters. The good news is that the inverters had a 10 year warrantee and it cost me nothing. The bad news is that the new inverters did not fix the problem, though for a brief period of time it appeared to fix one of the two panels. After some back and forth between Enphase, Lighthouse Solar and me, I appeared to have a solar panel failure. Sharp was not as cooperative as Enphase with replacing the panels which were guaranteed for 25 years.
Ultimately, I think that the original installer paid for a new panel and when this spring arrived, Lighthouse Solar made a second attempt at repairing the system and replaced a solar panel. Once more Lighthouse Solar came through for me and got the repair done at no cost to me. Unfortunately, after replacing the solar panel I now have one failed panel and one panel working at partial capacity. After speaking once more to Enphase Energy, Lighthouse Solar now says that they will try new inverters. There are a limited number of components that could have failed, but unfortunately since Lighthouse Solar has to fight to obtain each component for me under warrantee, they have been unable to simply replace everything at once and get the problem solved. The actual cost of buying and replacing all the potentially failed portions of the system would cost more than a year’s worth of power production of the entire system.
All solar PV panels degrade and slowly over time produce less power, however based on news report there appears to be a cluster of failures after a couple three years. Solar photovoltaic panels have no moving parts so that the operating life of the solar panels is largely determined by the stability of the coating film, the quality of finish and fit of the panels and the proper sealing of the edging and connectors. Quality control in manufacturing is essential to have a solar panel that wills last 25 years in sun, rain, sleet and snow. The quality and life span of these rapidly produced solar panels is about to be tested in the next few years.
Without micro inverters a failure of one panel in an array like mine is a 3% reduction in power production and might not be noticed, it could be attributed to decreasing efficiency of the panels or weather variations. In Ed Begley, Jr.’s “Guide to Sustainable Living,” he said that over the years he had four solar panels fail, his storage batteries were replaced after 15 years and the wiring for the panels were damaged and needed to be replaced at 18 years. So, these systems are not trouble free even in sunny warm California, you cannot just install them and forget it. The President is only going to be living with the White House solar array for less than three years so he will not have to worry about maintenance, but as a nation we need to maintain our clean energy infrastructure. In my calculations of cost and return I was conservative on SREC value, but I did not consider maintenance costs or loss of power production due to equipment failure. I am on net metering and still connected to the grid so I continue to get all the power I need from the grid. I have spent a lot of time and effort on trying to get my solar panel array repaired without yet succeeding. Nothing magically maintains itself, consider maintenance and repairs whenever buying equipment.
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| map dwell example of cost and return |
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