Monday, July 19, 2010

The Cost of My Solar Panels

One of my choices when I purchased my solar panels was to 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. If there should be a problem with the system, I can easily identify which panel needs to be attended to. However, 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 to make sure all the panels are performing optimally. Though each panel is rated at 230 watts the rated PTC output per panel is 203 watts. The micro converter efficiency is rated at 95% so theoretically maximum actual production per panel is around 193 watts. I regularly see that watt output or slightly above at midday if a cloud is not floating by. Just by viewing the Enphase web page I can verify the proper functioning of my system.

For the first month of full operation (the panels were actually installed on the first day of my billing cycle) I checked the use of electricity on the solar on demand digital meter, added my recorded solar electricity production and compared it to my overage daily summer use of electricity twice a day. We use air conditioning. I am old enough to remember a time before air conditioning was common, but it is not a time I want to return to, not here in Virginia. A few weeks ago when my electric bill actually came, our power usage was slightly more than half of what it had been for the same period last year. My husband has taken to telling the neighbors who ask how much power we have that we have more solar power than Ed Begley, Jr., which is true. I believe we also use more power than the Begley household does. My husband explains this as a reference like saying a place is a little bigger than the state of New Jersey.

The energy produced by the solar panels has gone a long way in erasing the memory of my misadventures in solar that were topped off by actually finding a roof leak. I finally discovered the leak when the water began dripping in my first floor office during a thunder storm. Fortunately, rain storms make finding a leak easy. The solar installation company was actually a subsidiary of a roof and gutter company and was able to verify the location of the leak (and a few other nail pops) and dispatch a roofing repair crew (with full safety equipment) in the rain. The last few thunder storms have confirmed the integrity of the repair. Last week the wall board damage from the installation and leak were finally repaired and painted. The house looks good as new (or at least good as before the solar panels were installed). I just need the final bill from the contractor for the interior repairs to my home to deduct from the retainage and make the final payment to the solar installation company and we are done. Both the solar installation company and I are looking forward to that moment. Though it has been a bumpy road, they have always been responsive to problems and nice.

So, what did the solar project cost? The answer to that question is not simple.
To 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. Now it gets complicated. The 7.36 KW 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 may or not be taxable income. When I file my federal tax returns at the end of the year, I will have to provide copies of all the documentation for my federal tax returns as well as evidence that Virginia paid my Renewable Energy Rebate to obtain my 30% tax credit of $17,562. 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 $17,562 and my total out of pocket cost for my solar system after the first year is $28,978. 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 an under 5% 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. In the first two months of operation, my system has produced 1.9 megawatt hours. 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 the state buy 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. Other states, like Virginia, have no current RPS requirement. Still other states, like Pennsylvania allow their utilities to buy their RPS from any resident within the PJM regional transmission organization.

Within the PJM (where my house is located) I can currently sell my SRECs to utilities in Pennsylvania and Washington, DC. I need to have my solar system certified by both Pennsylvania and Washington so that I can sell my SRECs in their states. Once the system is certified, I can sell my solar power by estimate on the spot market or I can shop for a long-term SREC contract. The discount for a long term contract is huge. The value of SRECs will go up and down depending on the supply and demand as determined by the number of solar installations, states requiring RPS, and states allowing sale within the PJM regional transmission organizations. RPS requirements are currently set to increase over time, but regulations can change. SRECs in Pennsylvania have ranged from $200-$300 per megawatt hour. So after having my system qualified in Pennsylvania, I could earn an additional $2,000-$3,000 a year for 15 years or as long as the demand for RPS lasts which ever is less.

The bottom line is that I paid $58,540 for a photovoltaic system of 7.36 KW and we the American tax payer, and PJM power buyer will pay hopefully $29,562 in the first year for my solar system and maybe pay up to another $30,000 (or so) over the next 15 years.

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