We are installing a photovoltaic (PV) power system on the warehouse portion
of the Green Institute building at 2801 21st Avenue South, Minneapolis, which will provide supplemental electric power during the day, especially on winter mornings and summer afternoons. The PV module for this system will be the Millenia series by BP Solar, rated at 43 watts peak power per module.
Our master electrician and crew will complete the wiring of the PV power system, and make the connection to utility power.

The solar array will consist of a 30kW array of PV modules on the flat roof area, and another 5 kW array, mounted awning-style at the top of the west wall. The roof array will include about 700 of the modules, deployed on ballasted racks, and tilted 35° from the horizontal, at a direction of 23° east of south. The modules in the wall array will likewise be tilted 35°, at a direction 67° west of south. The rooftop is already host to a field of skylights; we will locate the racks of PV modules so as to avoid interference with the day lighting system.

We have added a battery to the system in order to utilize equipment made by
Outback Power Systems for the grid-connection. The DC power generated by the solar array will be fed to the battery. As the battery will normally be
fully-charged, the PV power will typically flow through the battery and be
blended with the utility power at the main circuit panel, for use throughout
the building. Any instantaneous surplus will be sold back to the utility. A
bank of Outback inverters (rated at 3.6 kW each) will draw the
solar-generated power from the batteries, and synchronize to utility power.
The system will include safety and monitoring equipment to meet electrical
code requirements.

Since there is a battery in the system, we will have some back-up capacity available for high-priority, low-power loads. A back-up power circuit, with a small inverter and sub-panel, can be added to the system to make the back-up function usable for the tenants.