As the residential solar photovoltaic boom continues, solar contractors rely on the manufacturing sector to deliver solutions that will keep the wheels spinning beyond the expiration of the Federal Investment Tax Credit (ITC) at the end of 2016.
One such technology innovation is coming in the form of refining and improving module-level optimization. Using maximum power point tracking and smart DC electronics, sub-array optimizers have the potential to lower equipment and installation costs.
Where we’ve been: String inverters and MLPEs
The limitations of using string inverters alone in handling solar PV performance are well-known. For starters, a traditional string inverter won’t provide optimal outcomes for complex rooflines, partial shading or really any scenario in which the PV array’s voltage can dip. Then there’s the NEC Rapid Shutdown requirement, which, for string inverters, means including an additional hardware component.
MLPEs like microinverters and DC optimizers overwhelmingly solve both of these problems. With MLPEs, your array’s performance is maximized and your system is Rapid Shutdown compliant.
Many manufacturers offer MLPEs meant to be placed on every module. While this provides a high level of resolution, this also requires installing and caring for more equipment.
Another optimizer option
Pike Energy offers DC optimizers that work with its islanding inverters and fasten to the PV racking just like other market options, but is only required for small substrings, not every individual module. This allows the installer to design substrings, typically of 2 to 9 standard-efficiency modules each, to create a system that increases installation speed and reduces installed components without sacrificing array performance. For example, on a small partially-shaded face of a roof, a small sub-array can be isolated with its own sub-array optimizer, so it doesn’t lower the voltage of a larger sun-soaked array using its own sub-array optimizer on the adjacent roof face.
Why is this important?
Getting the speed and simplicity of PV installations right is not just a matter of convenience and preference for installers. It’s becoming a requirement to help preserve installers’ businesses beyond the expiration of ITC. When installers lower their cost-per-watt charges to remain competitive after ITC, they’ll rely upon clean, fast, agile installations with reduced warranty calls to keep soft costs to a minimum.
“A sub-array optimizer is simple to integrate into large or small PV systems, and is a more robust option than individual optimizers on every panel,” said Rachel Taylor, project manager for Assured Solar Energy in Maine.
The technology advancements of recent years have precipitated the residential PV boom, and now with sub-array DC optimizers, that boom can continue beyond 2016.
Expect to see more manufacturers announcing sub-array DC optimizers in the coming months. Increased competition for smart inverters and simplified residential solar-plus-storage systems will urge manufacturers to meet the mounting needs of system integrators for dead simple, fast-installing hardware that leaves everyone happy.
By Chip Means, Director of Sales Development, Pika Energy
