Energy Storage & DC Lighting - Optimizing Microgrid Solutions

Energy Storage & DC Lighting – Optimizing Microgrid Solutions

by David Mandell

Current Problem

Lighting downtime caused by AC grid failure, outages and other threats has generated organizational safety and financial risks, expanding the need for emergency and back-up lighting, as well as primary lighting systems powered by DC renewables and microgrids. Further, the cost of AC building power continues to increase, and lighting costs represent an average of about 50% and may represent as much as 70% of power usage.

The DC Solution…“DC Lighting is the Key to Optimized Microgrid Solutions” (PNNL, 2020)

With the advancement of renewable power technologies (battery storage, solar PV, wind generation), DC lighting addresses the evolving need for renewable, modular structure, and off-grid infrastructure solutions.  DC promotes cost savings and reduced carbon footprint benefits via direct connect-ability with battery storage and other renewable DC power sources, further expanding electric control costs and efficiency capabilities.  By offering the flexibility of sharing lighting power consumption among various power sources, this further optimizes control of electric source usage and costs through “strategic load sharing”.

DC Lighting & Renewables

Lighting is moving towards DC power inputs (24DC, 48DC, 125DC), aligning nicely with battery storage systems and solar PV panels. Net-zero energy buildings will generate, store and consume power in DC, and research forecasts that commercial buildings will save 15% of total power by foregoing the DC-AC-DC inversion process. New infrastructure developers are creating electrical infrastructures for commercial buildings that use DC as the primary backbone throughout the building.  This notion represents an imminent evolution poised to transform the electrical infrastructure.

DC System Components

The DC lighting system is typically comprised of a DC distribution network, specified to supply DC power to at least a portion of the building to supply ample power to the DC lighting load(s). The system also includes a DC power source or sources having a DC power output (typically 24DC, 48DC, 125DC), such as a rechargeable battery and/or solar PV array, directly-coupled to the DC distribution network to provide DC power to the lighting grid.