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In Part One of this three-part Case Study we learned how Westridge School chose Run on Sun as their solar contractor. Here in Part Two we focus on the actual process of the installation as seen from the client’s perspective.
With the paperwork filed and the rebate secured, Run on Sun had a very tight window — less than two weeks in April 2012 — in which to install and connect all 209 solar modules and get the monitoring software up and running. The goal was for the project to be completed and operational by the time Westridge students returned from Spring break, so time was of the essence.
For the rooftop display Run on Sun used a microinverter system supplied by Enphase Energy, which allows customers and solar installers to track the output of the modules, individually or collectively, from the convenience of their computers, iPads or smartphones. This software was a selling point for the school, because it would make the technology accessible to students and allow teachers to creatively incorporate aspects of the solar system’s performance into classroom instruction.
The modules were grouped into three sub-arrays that formed a larger circuit. Under each module, a microinverter was installed to convert DC energy gathered from the module into AC power, which could be combined and fed back into the school’s electrical service. The 1:1 ratio of microinverters to modules allows for a more detailed readout that lets users know the output of each module and gives an easy-to-read display should anything ever go amiss, from a connection issue to dirt on the module’s surface.
Throughout the installation Williams remained on hand to oversee the work, though there were no delays and no change orders requesting funds beyond what had been originally estimated. Within the assigned two-week period, Run on Sun had completed the project on time, and everything was in working order.
“I’ve worked with a lot of contractors, and I can honestly say, in this situation, this was one of the most seamless projects we’ve ever completed,” Williams recalls. “They were here early on the first day and, boom, they got it. It was done on schedule, at the price they said and signed off by the city. I wouldn’t hesitate to do a project like that again.”
April 2013 marked the one-year anniversary of Westridge School’s solar installation, and Williams reports the system is running smoothly. The Enphase software makes it easy for officials, teachers and students to monitor the activity of all 209 modules, but Run on Sun also keeps a close eye on the operations and reaches out if and when an anomaly is detected. In the event that an outage or a decline in energy production should occur, the company promptly notifies the school.
For example, when one of the modules stopped reporting and apparently needed to be replaced, Run on Sun immediately contacted Williams to schedule a visit. The rest of the modules were still in full working order, and upon close inspection it was revealed that a connection had come loose. Still, to ensure maximum performance, the company replaced the microinverter at no cost to the school.
Another time Williams received a notification email from Run on Sun after the campus Internet connection had been temporarily cut during some service upgrades. And when the energy dipped from its norm of exceeding system predictions to 98 percent of anticipated, a call came in with a recommendation to check the array for accumulated dirt. After a brief spray with a hose, the system was back to producing at maximum capacity.
At the one-year mark, the school became eligible to receive its first annual rebate from Pasadena Water and Power. This is the first of five annual rebates it will receive, the dollar amounts directly correlated to the system’s actual production.
When a technician came from the city to assess the energy output of the system, the school was excited to learn the results. The city’s readings gave some very welcome news, indeed — the energy generated by the installation was above and beyond the original estimate provided to PWP, and it looked like the first rebate would be larger than anticipated.
“He said, ‘You’re over your estimate,’ and that’s all we could ask for,” says a thoroughly pleased Williams. “To date, everything that was promised to us was delivered — plus.”
In terms of the amount of energy generated, the rooftop system has continued to outpace expectations. The school expected to see a return on its investment in seven years, but it’s shaping up to come in as few as six. Because of the installation, Westridge is using 30 percent fewer kilowatt hours and is seeing its bills reduced by thousands of dollars each month, in addition to the rebate. The overall savings is far greater than the cost of running the air-conditioner in the gym, the initial impetus for bringing solar to campus. To Williams, making the decision to go solar was a “no-brainer.”
“The neat thing about this is it runs itself. If somebody walks onto campus, they don’t know we have a 52 kilowatt solar system on campus,” he adds. “They don’t see it. It doesn’t impact anything. All you do is save money.”
We will conclude this three-part Case Study with Part Three - Advice for the Solar Reluctant.
The preceding is an excerpt from Jim Jenal’s upcoming book, Commercial Solar: Step-by-Step, due out this summer.