Solar Panel Failure

My solar power output on a cloudy morning-note the failed panel

On the back of my house facing almost dead south is a roof mounted 7.36 KW solar array consisting of 32 Sharp 230 watt solar photovoltaic panels and 32 Enphase micro-inverters. We decided to go with Sharp Solar PV panels because when I made my purchasing decision in 2009 Sharp had manufactured 25% of the solar PV installed at the time and had been in the business for over 40 years. Sharp had continued to invest in the research and development of photovoltaic solar panels at that time, but since has suffered crushing competition by less expensive manufacturers. The Sharp panels put out almost 10% more wattage using the same square footage than many competitors and allowed me to fit the 7.36 kilowatt array on the main roof section avoiding any shadows from vents. The Sharp panel sold in the United States was manufactured in their Memphis Tennessee plant, which in 2009 had produced over a million panels.

The final point in their favor was the Sharp modules met the intent for the “Buy American” provision in the stimulus bill which provided the funding for a renewable energy grant I obtained from Virginia. When I purchased my solar panels I also choose the Enphase micro inverter system. Though this system was more expensive than a single power inverter, it does two things for which I was willing to pay. The first is that the power cables running down the side of my house, albeit inside a pipe, are 120 current instead of 240. The second advantage to the micro inverters is that the energy production of each individual panel can be checked on the internet.

I have gotten in the habit of checking my solar panels production numbers every month when I get my power bill. I am on net metering with NOVEC my power cooperative to sell my solar renewable energy certificates. I managed to register my system and get grandfathered into the Washington DC SREC market before 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. After two months of checking several times a day, 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.

Shortly before the New York Times reported emerging problems with some solar installations in a story about solar panels covering a vast warehouse roof in California failing less than three years into their expected 25-year life span, one of my solar panels appeared to fail. While I was attempting to have my solar system serviced a second panel appeared to fail. The company I hired to install the system was no longer in the solar business- without renewable energy rebates and a viable solar renewable energy certificate market, there was not enough business to sustain a solar installation operation in Virginia. They were focusing instead on energy audits, but they referred me to a Maryland and Washington DC based installer, Lighthouse Solar.

All solar PV panels degrade and slowly over time produce less power, however there appears to be a spreading of failures at two to 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 will last 25 years in sun, rain, sleet and snow.

The quality across the industry (and not just on my roof) has been brought into questing by the rising number of panel failures being reported in the media, though I could find no statistics. It is not just the less expensive Chinese solar arrays that are failing, the California warehouse failure reported in the New York Times reportedly has panels manufactured by an American Manufacturer. Solar panel power generation capacity grew from 83 Megawatts in 2003 to 7,300 Megawatts in 2012 with over 3,500 Megawatts installed in 2012 alone.

The quality and life span of these rapidly produced solar panels is about to be tested in the next few years. Also, 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.

Enphase trouble report

It took almost two months for me to identify another company and get 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 and they were able to replace both inverters on the same day. According to the Solar Guys who prefer to remain nameless, 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 only fixed one of the two panels. After some back and forth between Enphase, Lighthouse Solar and me, I appear to have a solar panel failure also. Though I am on the back burner, Lighthouse is attempting to get a replacement Sharp solar panel and I hope before winter to have the panel replaced. Otherwise it will have to wait for spring. Since it is only a 3% decrease in power production, I will attempt to remain Zen about the timing and hope that Nick can locate a Sharp panel soon.

Solar Power, My Tax Returns and My Electric Bill

I electronically filed my tax returns and now that the threat of a government shutdown is past I am looking forward to receiving my refund from my renewable energy tax credit shortly. With my tax returns I filed form 5659 Residential Energy Credits Part II to obtain my tax credit. In summary, too purchase and install a 7.36 KW solar array consisting of 32 Sharp 230 watt solar panels, 32 Enphase micro-inverters and mounts was $57,040. For the engineering and permits I paid $1,500 for a grand total of $58,540 out of pocket. (Last winter while interviewing a solar photovoltaic purchaser I discovered that the solar market is cheaper in San Francisco than Virginia which I suppose was no surprise.) Calculating the final cost of my solar panels is complicated, but I will walk you through it.

The 7.36 KW gross are equivalent to 6.2 KW PTC. I reserved 6 KW PTC Renewable Energy Rebate from Virginia and on completion of installation, inspection by the county, and sign-off by my power company, NOVC, I filled out all my paperwork, provided copies of permits, signed off inspections, invoices, technical information, contractor information and pictures of the installation, and meter and promptly (within 4 weeks) received my renewable energy rebate of $12,000 from Virginia. This payment is not taxable income, but according to the Commonwealth of Virginia, the Federal Tax instructions for form 5659, my accountant, Scott Price, and research performed by Andy Black, the payment reduces the cost basis of the solar system that the federal tax credit is calculated on. A tax credit is more valuable than an equivalent tax deduction because a tax credit reduces taxes dollar-for-dollar, while a deduction only removes a percentage of the tax that is owed. My 30% tax credit is calculated on $46,540 and was $13,962. Thus, from the original installation cost of $58,540 I subtract the Virginia Renewable Energy Rebate of $12,000 and the 30% tax credit of $13,962 and my total out of pocket cost for my solar system after the first year is $32,578. A rough estimate using the DOE model of my savings on electricity (I have an air heat exchanger) is $1,400 per year. That is slightly over a 4% return on my investment each year.

However, that’s not the final cost. The cost and return on a solar power system is based entirely on regulated incentives and there are more. The final incentive is the Solar Renewable Energy Credit or SREC. Each SREC is a credit for each megawatt of electricity that is produced. SRECs have value only because some states have Renewable Portfolio Standards, RPS, which require that a portion of energy produced by a utility be produced by renewable power. Utilities in some states can fulfill that requirement by buying SRECs from solar installation producers. It is a way for states to ensure that the upfront cost of solar power is recovered from utility companies (and ultimately from the consumers). Some states, like New Jersey and Maryland, require their utilities to buy SRECs only from residents of their states creating a closed market where the price is very high. Some states, like Virginia, have no current RPS requirement. Other states, like Pennsylvania allow their utilities to buy their RPS from any resident within the PJM regional transmission organization (at least for now). Still other states like California do not allow the purchase of SRECs to meet RPS requirements. I am currently selling my SRECs in Pennsylvania. SRECs in Pennsylvania have ranged from $180-$300 per megawatt hour recently. So, I could earn an additional $1,800-$3,000 a year for 15 years or as long as the demand for RPS lasts which ever is less. This past year I earned $1,045.94 in SREC income for the partial year that my panels were installed. This income needs to be reported on your tax returns. You report the total dollars received in SREC payments during the calendar year on Line 21 of the 1040 form-other income.

After the tax exercise and calculating my total return I was not feeling particularly excited about my solar panels and this was compounded by having nothing but trouble with the Enphase micro converter system that is sending a constant stream of error messages. Nonetheless, several service calls to the solar company identified the problem as a network and monitoring problem. The solar panels continue to work and produce power into the grid. The customer service for the installation company is virtually non-existent for the Enphase micro converter and the customer service at Enphase was virtually useless to me though I did buy another router to boost the signal of my internet.

Two days after filing my tax returns, I received my electric bill for $55.17 (compared to the $213.53 for the same month last year). That was a quick way to regain the joy with my solar system. Though, I have more solar panels than Ed Begley, Jr., my panels in Virginia do not have quite as many sunny (and not covered with snow) days as Ed’s panels in Southern California and in truth my multiple refrigerators and freezers and my air heat exchanger consume a lot of power. Only when my heat pump is operating within its most efficient range and cycle combined with the insulation and passive solar steps I have taken are my electric bills this low, but it still felt really good.

The effectiveness of a heat pump is based on the temperature difference between the source and the sink and which cycle it is in. Heat pumps are more effective for heating than for cooling if the temperature difference is held equal. This is because the energy used to power the compressor is largely converted to useful heat when in heating mode and released into the house as extra heat. During the cooling cycle, the condenser is normally outdoors, and the compressor's dissipated work is rejected rather than put to a useful purpose. When the temperature is below 48 degrees Fahrenheit or above 90 degrees the air source heat exchanger becomes much less efficient and my electric power use soars.

The most effective type of heat pump is the geothermal heat pump. Like all heat pumps it doesn't create heat by burning fuel. Instead, in winter it collects the Earth's natural heat through a series of pipes, called a loop, installed below the surface of the ground or submersed in a pond or lake. As you may have experienced in a cave, the temperature six feet beneath ground surface is cooler in summer and warmer in winter than the ambient temperature. Using this temperature as its source the geothermal heat pump can operate within its most efficient range at all times. In winter, fluid circulates through the loop and carries the heat to the house. There, an electrically driven compressor and a heat exchanger concentrate the Earth's energy and release it inside the home at a higher temperature. I have not been able to find any calculators of cost savings I might experience by converting to a geothermal heat exchanger, only the grand claims of the manufactures. The American Recovery and Reinvestment Act of 2009 extended the tax incentives under the Energy Policy Act of 2005 (EPACT) and eliminated the limit on the credit and extended the tax credit until 2016. Like solar panels, geothermal heat exchangers are eligible for an unlimited 30% tax credit and I have four years to save up to buy a geothermal heat exchanger to replace my air heat exchanger that should be near the end of its useful life by that time.