BRINGING DC TO THE DC AREA

OVERVIEW

Energy independence is a chief national security imperative. Mandates for federal government installations require significant reductions in traditional, non-renewable energy sources in the next two decades.   

The Fort Belvoir (Alexandria, VA) Direct Coupling® DC Microgrid demontration project uses native DC renewable energy created by roof mounted photovoltaics as the primary power. Rectified AC grid power is only used when DC power is not available or is insufficient to completely power the DC loads.

In typical microgrid installations, DC power generated from renewable sources is inverted to AC current to access the grid, and then rectified back to DC for use in the load. Each conversion incurs energy losses ranging from 3% to 30%. Nextek’s Direct Coupling® DC Microgrid eliminates those losses.


SOLUTION

Direct Coupling® technology utilizes DC-compatible equipment that eliminates the need for most of these conversions/inversions, regulating the solar array and the power to the load, thereby reducing power loss in the system, which translates to energy cost savings.

Nextek donated the following equipment for the project:

  • (16) First Solar FS-416A Thin Film Panels totaling 800 watts
  • Nextek Low Voltage Maximum Power Point Tracking Controller
  • (2) Nextek Power Server Module Alt
  • (32) Nextek T8-32 watt 2 lamp ballasts and (1) Nextek T8-17 watt 2 lamp ballast
  • Required low voltage cable and connectors
  • STAR (Stationary or Transportable Available Resource) Trailer
  • PS Manager software

Renewable power was generated by the PV array installed on the facility roof or through the STAR trailer, and sent to the MPPT. The MPPT optimized power production and sent it to the PSM, which distributed it to the load and supplemented required power from the AC grid. This ensured non-interruptible power at the lowest cost. As DC source conditions changed the MPPT adjusted the new maximum power point without interrupting the output power flow