Putting It on the Line

A Net Zero Design and Build Solar Dream

 

 

By Harry Sawyer, harry@powerhaircut.com

November 2019

 

I am a Newark, New Jersey, native and current ten-year resident of Dripping Springs, Texas, with a background in the utility sector. I am involved professionally in electric transmission, distribution, and generation of utility scale wind, solar, and battery storage. I am an engineer, pyro-technician, and big proponent of the new energy economy. Marital status: Single.

If you are interested in reading about a project that was perfectly executed from start to finish and was completed ahead of schedule and under budget, you came to the wrong story. Still, my project may provide some lessons and inspiration to others who might do the same.

Inspiration

My wife and I moved to Austin in 2006 when I took a job with Airtricity, an Irish company investing in the Texas and national wind power industry. Several years later, we bought our first Texas home in the Ledgestone community on the outskirts of Austin and installed our first small, do-it-yourself (DIY) solar system. My neighbor remarked, “You know, there are people you can pay to do that.” It wasn’t until this project was complete that I truly began to understand the huge untapped potential of residential solar energy. With a mere ten photovoltaic panels on our garage, we became a Net Zero household, at least in the cooler months of the year. I thought, “Why would anyone not do this?”

This positive experience from my initial foray into solar inspired me to someday design and build a Net Zero system for every month of the year, which could handle our high summer load requirements in Texas. I also wanted the system to support an electric vehicle or two. While I was at it, I figured, why not design the system to track the sun throughout the day and milk the most energy possible? Trackers have a certain “wow factor” about them, and this element satisfied my final goal of building something unique and unusual.

Time lapse of author testing two-axis tracker into the evening. This 2.34 kW, 9-module array follows the sun throughout the day and throughout the seasons.

 

Searching the market for tracker technology, I could not find an acceptable product, so I decided to design and build my own. A coworker recommended a mechanical genius in Georgetown. He was all in, and we went to work building a prototype utilizing a two-axis slew drive manufactured by Kinematics. After some effort, we completed and tested the tracker, but it was too big for my small property. By this time, I had spent about $15,000 on the tracker and had no suitable place to install it! The tracker is basically a strong support column, a dual-axis motor, and an axle attached to strong arms that support a frame with solar panels attached.

Bird’s eye view from drone. The 54-panel, fixed array at top of image. 9-panel array atop tracker at bottom. A second tracker is currently under construction.

My first idea was to install the solar tracker at a friend’s business along highway 290W. I liked this busy location because it would bring a lot of attention to solar power. However, it turned out to be too difficult to convince anyone to contribute their time and money to a project like this. Even a solar energy company was not interested in installing my PV system at their business.

Several years later, I moved to my current home in Dripping Springs, which is a larger property with space for solar trackers. Unfortunately, the project sat for a few more years while I prioritized home repairs and the acquisition of various animals for a home zoo. Finally, I could wait no longer and committed to build a unified solar system with both fixed arrays and a PV tracker. My dream of building a system to achieve a Net Zero electric home began in August 2018.

Design and Build

Considering the house was over two hundred feet from the pole that supported the electric meter, the best solar solution seemed to suggest building a fixed, ground-mount solar array close to the service entrance pole, a dual EV charging station below the array, and two solar trackers with good sun exposure. It was important for me to establish a demonstrative link between solar energy and the electric vehicle. Every electric vehicle, of course, has the potential to be a sun-powered vehicle.

Conduit run.

The first job was to clear the area, which required hiring a Bobcat operator to remove some construction debris and fill a dumpster. This same contractor drilled eight holes in solid rock for the footings of the ground mount columns and two large, deep holes for the tracker footings. Next, I planned out my conduit runs from the meter to the array and from the array to the trackers. I rented a large rock saw and spent a day digging two-foot-deep trenches.

I then ordered the steel to support the fixed array directly from the mill, in lengths of roughly the correct dimensions. At this stage, I recruited help from a few friends to set the steel into the holes, mix the concrete, and set the stage for building the fixed array support structure. A neighbor did the welding to put the frame and supports together.

Author’s son, Paul. Just one more coat.

My ten-year old son and I painted the steel, coat after coat, to prevent corrosion.

Next up was the concrete and stone work. The stone would be an aesthetic touch, covering the block wall on the EV charger side. On the solar side, the wall provided space for mounting distribution panels and solar monitoring equipment.

I eventually decided to use microinverters on each solar panel to convert DC to AC, rather than a central string inverter. This decision was partially inspired by a meeting hosted by Solar Austin, during which the Enphase founder presented their new iQ inverter products. It turned out to be a great “plug and play” solution with no single point of failure. Also, my ground mount array experiences some shading from nearby trees, so the microinverter concept ensures each panel delivers the maximum energy available. If a little more power is needed, the trees can be trimmed back a bit, I thought.

Friend’s son, Derek, pulling wire.

Portions of the electrical work required an electrician, and fortunately I knew a good one who spent twenty hours with me in the summer heat to tie the solar and main electrical systems together. My friend’s teenage son did a good bit of the de-energized electrical work to pull the 100A circuits to the solar and charging locations.

Lessons Learned

Although I would like to take sole credit, in reality, a DIY project like this is only possible with “friend power.” Every friend has a capacity to help, but that capacity varies. The secret is to tap resources as they are available without creating a burden on your friends. People have lives, families, and their own priorities. Some friends are flexible with their time, while others are not, so some helped more than others. I ended up making better friends as a result.

Sometimes you cannot avoid paying for the expertise you need. Seek out and employ people who share your goals. Even when this is not possible, ensure your scope is properly defined and your expectations are conveyed. Show your appreciation for good work, and learn from the bad work.

There were nights that I found myself working in the dark, with a shovel or perhaps balancing my 250-pound body high in the air on a thin piece of metal while drenched in sweat. I asked myself more than once, “Can you do this?” A little voice in my head kept answering, “You’re the one. Don’t give up on your dream.” I pushed forward, and eventually my goal was within reach. The site was energized on August 8, 2019, and I’ve been Net Zero monthly since that day.

More advice to anyone wanting to tackle a DIY home solar project: make sure you are driven by the right goals. Electricity is cheap. If it’s just about the money, there are better ways to improve your finances. It’s more important to learn, share your experience with others, and help figure out new ways to live sustainably in this world. Resolve to do it right. Do your research, and search out the best practices, then apply them. Remember, quality work will deliver the highest value.

EV ready.

I am still working on owning an EV and expect to hit that goal sometime early next year. In the meantime, I would be happy to provide an EV charge for someone interested in seeing this installation.

This project would not have been possible without Paul, Rose, Lynn, Kurt (RIP), Charles, Tino the Taco Man, Conrad, “Dog House” Daryl, Roy, Jordy, Jesus, Bennett, Eric, Rudy, Tim, Bob, Derek, Adam, Nic, Mason, Guy, John, Mike, Juan, and of course the Pedernales Electric Coop (PEC).

PEC provided great support by quickly processing my interconnection agreement, pulling my meter for the line tap, and having a well-thought-out net metering program. PEC purchases my monthly net excess generation at the “avoided cost rate,” essentially what they pay the Lower Colorado River Authority for power.