A guest post by Rush Hood, P.E., and Jeffrey J. Basiaga, Jr.
The “IEEE FWCS Industrial Tour Series” sponsored a tour of the Landmarc Construction Net Zero Energy Building in Tampa on March 28, 2013 hosted by Mr. Spencer Kass, Landmarc VP. He has installed and is operating a practical, utility-connected, photovoltaic generation system. The office is approximately 2800 sq. ft. with lighting and HVAC fully within modern standards. The building operates at “Net Zero” energy consumption and returns surplus energy to the electric grid. There is an Electric Vehicle charging station installed and free EV-charging is provided to the visitors parked in the parking lot.
As with most engineering projects, there are many factors that are not obvious. A structural analysis was performed on the building to ensure it could support the weight and wind loading of the solar panels. Special electrical equipment ensures the safety of utility workers by disconnecting the solar generation from the electrical service when the utility power fails. This feature prevents energizing the utility conductors when utility workers would expect them to be de-energized. Additionally, a clearly-marked switch enables easy disconnect of the building generation from the utility in an emergency. Further, the physical layout of the solar collectors must ensure that no portion of the panels are ever shaded by the building structure or trees, as any shading would have a disproportionate impact on the solar generation efficiency.
The electric metering functions are not obvious, either. The meter does not simply “run backwards” when the solar generation is supplying power to the utility, since the utility does not pay full “retail price” for energy generated by the customer. A special meter keeps separate track of energy consumed from and supplied to the utility. “Consumed kWh” and “Generated kWh” appear as separate line items on his electric bill. Of course, energy generated on-site that offsets simultaneous usage on-site effectively gives the customer “retail price” for these kWh.
Participants also discussed other cost and expense factors that impact the payback of the system, including maintenance, lightning damage, surge suppression, potential for weather damage, and vandalism and theft avoidance measures. It turns out that the overall economic analysis of the project is very complicated, and at this time incomplete. The consensus of the participants, however, was that we were “Looking at the Future,” and we were all very impressed by the progress that has been made.
The engineers that toured the building were very grateful for the opportunity. We encourage interested parties to seek, learn about, and promote the cutting edge & practical realizations of great ideas.
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