May 13 2010
A new solar power installation at Big O Tires of Dublin, Calif., utilizes innovative parallel wiring technology from eIQ Energy to cost-effectively connect a 50-kilowatt generating system. The installation supplies 75 percent of the facility’s electrical needs.
The Dublin installation illustrates Parallel Solar’s ability to integrate different types of solar panels - a combination of cadmium telluride (CdTe) panels from First Solar and amorphous silicon (a-Si) panels from Signet Solar, as well as crystalline silicon panels from CentroSolar. All feed into a single Satcon 50-kW inverter. This heterogeneous approach allows array designers to leverage the strong points of each technology, so that the array can perform well under varying combinations of temperature and sun exposure.
Three a-Si panels, four CdTe panels, or one crystalline panel are connected to each vBoost module, taking full advantage of the modules’ power-handling capabilities while minimizing system costs.
The Parallel Solar architecture also enables greater lifetime power harvest from the array through its integrated Maximum Power Point Tracking (MPPT) capabilities. Unlike traditional series-wired arrays, which suffer loss of output when panel performance is not closely balanced, Parallel Solar arrays eliminate mismatches between modules. This was a factor in earlier attempts to design a practical installation for the Big O Tires Dublin center. Previous designs could not take advantage of all available space due to shading, and uneven dusting from nearby streets, and Service Center operations would have reduced production from some sections of the array, thus cutting overall performance.
Operators of the Big O Tires Dublin array will also be able to take advantage of the outstanding array monitoring capabilities incorporated in eIQ Energy’s Parallux system. In addition to operational and maintenance oversight, they will allow Big O Tire’s customers at the Service Center to engage with the installation, viewing real-time information on energy production on a constantly updated computer monitor.
“Seeing the panels starting to go up at the end of last year was a great feeling,” commented Bruce Cherry, who has run the franchise for 29 years. “Since the system has come on line in early March, we expect to handle most of our power needs with solar energy. The system’s production has been way higher than we anticipated. I’ve even seen moments where the total AC production is equal to the DC nameplate – that isn’t supposed to happen in solar systems.”
The Dublin array uses eIQ Energy’s vBoost DC-to-DC converter modules to create a parallel power bus that runs at a constant high voltage. The system inverter benefits from this predictable and stable power supply. Component stress is reduced, and the inverter always operates in its most efficient range.
“We’re very glad to be part of this project, which demonstrates the benefits of both our technology and of Parallel Solar at commercial scale,” noted eIQ Energy CEO Oliver Janssen. “As our products move into the field, we’re seeing that they make a tangible difference in the viability of solar installations of all sizes.”
eIQ Energy’s Parallux system uses advanced DC power management technology, incorporated in the vBoost module, to allow easy connection of solar panels in parallel rather than in series. This approach allows the connection of an unprecedented number of panels on a single cable. In the case of thin-film photovoltaic panels, the company’s Parallel Solar architecture enables the connection of over 100 solar panels on each cable run — a twenty-fold improvement over conventional string architecture. In combination with distributed MPPT, this enables solar photovoltaic systems to harvest 5 to 30 percent more energy than conventional systems.