By Mike Renner
It started back in 1986 when we lived in Arlington, Texas and had a solar water heating system installed on our home. At the time we received a compelling 60% Federal tax credit on the system, bringing the price down from $5,000 to $2,000, with $100 paid by our utility. The system provided us with about 85% of our annual hot water consumption and paid for itself in about seven years. The realization hit me that it’s smarter to own a solar hot water system than to in effect rent electricity from the utility to heat water.
After researching direct solar gain, we tackled another project ourselves and built a sunroom onto the house to reduce our winter heating bills. Appropriately sized overhangs on the south and an added porch on the east side of the sunroom protected the room from heat gain in the summer.
It was my research and then the desire for a wind turbine that led us to search for land outside the city limits. It is a difficult task to get a city permit for a wind turbine. Cities don’t care much for the structures and the mandated height restriction of 30 feet will not grab the wind speed needed for effective power. It would be like putting a solar panel in the shade. We found five acres of unimproved property northwest of Fort Worth and were on our way to a new energy efficient home and our mission, to build a life powered by renewable energy.
In the summer of 1998 with the help of family, we started construction on our energy efficient house. One of most important lessons of this journey was to invest in smart, solid, energy efficient design and construction. I cannot overstate this concept and approach. You will save money. You may want to create a large renewable energy system with a big wind turbine and a massive solar array, but it is smarter to build or remodel for efficiency first and then design an appropriately sized renewal energy delivery system. Energy you don’t use is energy that you don’t have to pay for, whether you are on or off the grid.
While we were planning and building our new home, the buyers of our former house did not care for the look of that old solar water heating system. They asked me to remove it and I took the opportunity to move the system to our new home. They soon asked why their electric bills were higher than when we lived there, and I reminded them that the system they considered an eyesore was an energy saver. That same solar water heating system is still working today and has paid for itself at least four times over.
Our next step was solar PV, but in the late 1990’s, the price per watt was still high. In 2001, I found some 5-watt solar panels for $35 each. I purchased two and set up a small solar charger for a 12-volt deep cycle battery, which ran a DC light and a fan. I was hooked and bought enough panels to create 100 watts of solar and added more lights to the system. This was my first solar PV system.
In 2002, I discovered Home Power Magazine, which became my main resource and teacher in the world of the renewable energy world. There was an ad for The Renewable Energy Roundup in Fredericksburg, Texas. I had to go! I could not get enough of the educational tent talks and subsequently I bought two Kyocera 120 watt PV panels. This was the start of the renewable energy system that we enjoy today, and I still attend the Renewable Energy Roundup every year.
By the end of 2003, our system grew to 10 panels and was rated at 1,200 watts DC. A 1,000 watt inverter was added to produce 120 volts AC and we used it to run a 5,000 BTU window air conditioner for about six to eight hours a day. This reduced the use of the central air conditioner, lowering our electric bill and providing a backup system air if for some reason we lost power from the grid.
It became a yearly habit to benefit from the 30% federal tax credit for renewable energy devices by adding a few more solar features. In 2005 I installed 5 more panels and the system grew to 1,800 watts. At that point the current draw on the battery system was too high, so I rewired the 12-volt system to a 48-volt system and replaced the 1,000 watt inverter with a 4,000 watt sine-wave grid tie inverter. Efficiency increased and I used smaller gage wires.
In 2006, my dream of a wind turbine came to pass. Though I had my eye on a 10,000-watt unit, I could not swallow the $25,000 price tag and the additional $10,000 for a 100 foot tower. I settled on a 3,000-watt Chinese unit at $5,000 and built my own 100 foot tower. The rule of thumb for a wind turbine is that it must be at least 30 feet above anything within a 500-foot radius to capture smooth air. You must plan for the future and remember that trees grow and towers do not. And the higher the wind turbine, the more power produced. The wind capture is stronger the higher you go.
By 2006, the 1.8kW solar system and the 3kW wind turbine produced 5,368 kW hours annually. We still had one of the old mechanical electric meters on the house and from time to time, I watched it turn backwards as it sent power back to the grid. One day out meter reader saw the meter run backwards and his eyes lit up! I had to explain I was not stealing power and gave him a tour of the systems. As a result, next came a suspicious engineer from our utility and my education in the institutional and naive barriers to solar and wind power began. The engineer agreed the system was sound, but he handed me a net metering contract specifying I pay a $500 contract fee, an extra $12 a month service charge, plus secure a million dollar liability insurance policy for linemen safety in the event of a grid outage. I explained the insurance policy would not prevent an unfortunate death, but the UL certification on my equipment insured the system would shut down in the event of a grid outage. He agreed to the adequacy of my liability coverage, but arranged for a digital meter that only reads in one direction, the power we consume from the utility. What we produced and sent to the utility was not recorded
And this is where we are today. We know what we consume from the grid but what they receive from us is not acknowledged.
In 2007 I learned don’t buy cheap. That 3kW wind turbine broke and I purchased the Bergey 10kW wind turbine I wanted in the first place. We also increased the solar PV to 2.8 kW and added a second 4kW inverter to the system, and a year later we increased the PV to 3.6kW. That year the combined system produced 13,852kW hours.
In 2009 the system produced more power than the two 4kW Xantrex inverters could handle and caused them to fail. The repair took two months, so I purchased two Xantrex 6kW inverters to get back on track. When the old and repaired inverters finally returned, I put one to work powering a solar trailer. The trailer consisted of a 780-watt PV system with battery backup. The trailer has been expanded and it is now a fixture at outdoor events throughout the state. It has powered an untold number of sound stages, keeping the music alive wherever the sun shines, which in Texas is just about everywhere, everyday, all the time. At our home, the trailer boosted the system to 4.4kW of solar PV with a total of 500 amp hours of battery back up at 48 volts.
400 watts of PV was added to the solar trailer in 2011 and I reinstalled the panels so they can be adjusted to follow the sun from east to west, increasing output between 15 to 20 percent. This increase in power inspired me to build a solar tracker, consisting of a pole mounted with 1kW of PV, tracking east to west, a satellite actuator, a deer feeder timer to move the panels, and the ability to adjust the tilt for summer and winter settings. We were given two 200-watt panels that I mounted on a small A-frame that can be adjusted east and west and plugged into the trailer. With these three additions, our total house PV was now rated at 6.2kW.
With the installation of a whole-house, web-based energy monitor, we could finally measure our energy production. Of course, we were directing clean power to the utility and buying it back at night. So we altered the time we used many of our high energy use appliances. We have installed two window AC units, one upstairs and one down, to use the solar power produced during the day, which dropped the summer daytime temperature in the home to 68 degrees. Because of the energy efficient construction, we avoid powering up the central AC at night. We also run the well pump during the day to water the garden.
In March of 2012 I built a second solar trailer, consisting of 2.2kW solar PV. I pulled the 4kW inverter and the 200-amp hour battery bank from the old trailer, included the other repaired inverter and yet another 400-amp hour battery bank and installed them on the new trailer. This total system, house and trailers, is now rated at 8.4KW of solar PV with a total of 900-amp hours of battery backup.
By October 2012 we were sending our utility company four times more power than we consumed from them annually. In 2012, we produced 18,982kWh. With our larger battery backup, it was time to switch off the main breaker from the grid to see how long we could go on our own power. As I write this in late February, we have not yet run out of power. Neither the backup generator nor the grid has been switched on. We have altered daily habits, like consciously running the hot tub and doing laundry when the power from the sun and wind is strongest. We are required to pay a $15 service fee to our electric provider, but the last three electric bills read $0.00 for power consumed. We are considering dropping our relationship with the utility company but for now it’s a nice backup. We are satisfied to know that not only do we own our power but also our household is producing clean energy that does not use the massive amounts of water and fossil fuels consumed by traditional electric producers. Our household carbon footprint is approaching zero.
Mike Renner is the president of TXSES chapter North Texas Renewable Energy Group. He is a tireless educator on the topics of solar and wind energy, and he can now speak about the joy of pulling the plug on the grid. In April he and his Solar Trailer could be found at any number of Earth Day events. For pictures and more about the Renner home, please click here.