My Experience with Solar City
The Basics
In June of 2011, SolarCity installed a 3.225 kilowatt grid-tie solar system on the south facing roof of my townhome in Dallas, TX. The price all in, including taxes was $7,585.10. This was the out of pocket expense and does not include tax deductions. I was able to get a tax credit for about 30% of the price, but this will depend on your individual tax situation and the rebates available each year. My system consists of 15 panels that can generate 215 watts each. The panels are wired to the inverter (to convert the panel DC to AC) which lives in the garage. There is also a small box that sits inside the house that wirelessly connects the inverter and monitors the system's performance and reports back to SolarCity via the Internet.
I am currently paying an average of 10.4 cents a kilowatt hour for electricity, which means the system could theoretically generate over 33 cents an hour in electricity savings, although the realized power output is always lower than the maximum (more on that below). Since this is what is known as a grid-tie system, there are no batteries to store excess power. When my electricity demand is exactly met by the solar panels during the day, my meter is motionless. If I need more power, I draw it from the grid at normal electric rates. If I produce more than I use (which does happen), I sell it back to TXU at 7.5 cents per kilowatt hour. When the grid is down, my power is down too.
If you aren't familiar with power measurement, an LED light bulb might require 10 watts to run. If you had a solar system that generated 1 kilowatt (1000 watts), you could run 100 of those lights (that required 10 watts each). If you ran those lights for 1 hour, 1 kilowatt hour (kWh) of energy would be consumed.
The Solar Panel Installation Process
Solar City sent an engineer to do a preliminary inspection to measure the supports in the attic and make sure the roof had a good south facing angle. From there the plans were drawn up and a few weeks later installation began. The installation of the solar panels and mouting system was remarkably fast, with most of the work taking just two days.
I don't have a Homeowner's association, so there were no issues there to worry with as far as installation restrictions. Some HOAs have rules against solar panels, so be sure to check with them before starting. Since I was installing to the third floor roof, the neighbors don't really see anything from street level.
The installation team was very professional and took the time to explain everything that was happening and how the system worked. The entire system has been completely maintenance free. If I could reach them, I would clean the panels occasionally, but since they are on the third floor, I let the rain do it naturally. We have had a few mild hailstorms since the installation, and no problems with the panels. Some people have even reported it lengthening the life of their roof, although I haven't had them on long enough or replaced the roof to be able to comment on the longevity of the roof with solar panels.
Download the SolarCity Welcome Kit
The Power Company
This is the Sunny Boy inverter that is installed in the garage. It converts the direct current from the solar panels into alternating current that is used by the house.
My electric company is TXU. From their perspective, what I am doing is called 'Distributed Renewable Generation (DRG)' - sending the excess solar power that I generate but don't use to them. When the solar panels produce more power than I use, my electric meter actually runs backwards, which is incredibly satisfying to watch and results in a small bill credit (TXU currently pays 7.5 cents per kWh that you send back to the grid).
If a power company purchases DRG energy, it will be listed on the Electricity Fact Label (EFL) that the power company publishes for each electric rate plan. The companies in my area that were willing to purchase excess power were TXU, Reliant, and Green Mountain energy. They all have different policies, but TXU had the highest repurchase rates (7.5 cents per kWh) and their phone reps seemed to be the most familiar with the process.
The Results
The first thing to note is that you will never achieve the maximum possible performance of the system (in my case, 3.225 kW). That is in a perfect siutation with no clouds at a perfect angle to the sun. You should not expect your solar system to continuously deliver the maximum possible energy, well... ever. For my system, generating just over 2 kilowatts at noon is the norm for a very sunny day.
The graph above shows the percentage of consumed electricity generated by the solar panels each month. The darker blue areas at the bottom of each month are the excess solar that I sold back each month.
10.4¢ |
average price per kw/h from the grid |
$1,990.82 |
total paid for grid electric this year |
$2,312.29 |
what I would have paid without solar |
$321.47 |
in solar generated electricity |
13.9% |
of my electric consumption generated by solar |
$95.07 |
additional credits for selling excess solar |
$416.54 |
total savings for the year |
It's important to remember that these are my results for a small, relatively inexpensive system. It is entirely possible to build a solar system that meets 100% of your electric consumption and sells excess to the power company. Your results will also vary based on the orientation of your roof, size of the system, number of sunny days, etc. Costs are always coming down while panels are getting more efficient at converting sunlight to energy. There are also various government subsidies that come into effect from time to time that can help with the initial cost.
Having the panels on the house will definitely add to the resale value, particularly for more environmentally conscious buyers. We will probably rent the townhome when we decide to move, and having the solar system is a unique selling feature, and the lower electric bills may possibly allow for slightly higher rent. Check out my other articles if you are interested in buying a solar home or selling a solar home.
How to Get Started with SolarCity
If you have found this information helpful, and are considering getting panels installed on your home, follow this link to get started with SolarCity. Sign up with your name and address and SolarCity will send a solar welcome kit and analysis of available sunlight in your area.