By Chris Janin, program director for solar energy technology, and Tim Galligan, instructor and editor, at Ecotech Insitute
As the price of solar drops, small margins—even as small at $.05 per watt—will separate the successful solar entrepreneur from the also-ran. People and companies able to adapt to changes and maneuver through the moving parts of the solar industry will quickly rise to the top. Two changes in NEC 2014 are testing this maneuverability.
The first of these changes is the increase from the 1000-V standard to 1500 V. This change, a result of market needs, increases a per-string load by 50% for commercial installations.
The second of these changes is the rapid shutdown requirement, which can lead to increased system complexity and, for that reason, costs.
As I mentioned, it is how people in the industry respond to change that will define their success. Taken individually, the first change appears to have a limited impact using traditional string-based electronics. The second looks to be an expensive, though necessary, safety feature that will be rolled into system costs. However, if we look at how these two interact, as well as recent improvements in corollary technologies, the changes can help us achieve that $.05 per watt margin.
Having to implement rapid shutdown on strings makes module level electronics, such as DC to DC optimizers and microinverters, a much better proposition. What was once a more expensive option is now on par with or better than the alternative. Module level electronics serve to reduce the system complexity introduced by the rapid shutdown system, making systems faster and easier to install, offsetting increased component costs.
To further decrease complexity, we look to the 1500 V standard. A hypothetical system in the 1000 V standard may have 60 modules per string, with 30 DC-DC optimizers. A 50% increase per string, to 1500 V, achieves the same power in two strings as three 1000 V strings. This allows for simpler design and fewer conductors and source run components. Again, cost is saved by simplicity and component count. It also reduces labor because there are fewer strings or branch circuits and parts.
As implementation of these standards develop, manufacturers and installers work to find the most efficient system architectures, and municipalities embrace the move toward distributed generation, those pennies per watt will make all the difference.
Ecotech Institute in Aurora, Colorado (Denver metro area) is the first and only college entirely focused on preparing graduates for careers in the fields of renewable energy, sustainability and energy efficiency. The college offers associate’s degree programs designed by experts in the industry for people seeking renewable energy jobs in the rapidly emerging clean tech economy.