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Energy & Grid Management
David Mandell
David Mandell
 · Posted in Energy & Grid Management

Empowering Grid Resiliency & Optimizing the Value of Renewables with DC Lighting

Empower Grid Resiliency & Optimize the Value of Renewables with DC Lighting

David Mandell

Renewables + DC Lighting = Optimized Load Sharing

In the new era of DC renewable power and AC/DC hybrid building nanogrids, DC Lighting adds sustainable value to DC and renewable projects.  “Direct-Connect” of DC lighting with renewables (solar/battery) is key to unlocking optimum lighting security, cost control, and load sharing possibilities; offering greater stability & efficiency, decreased carbon footprint, and options to mitigate risk of lighting loss.

Since lighting often uses over 50% of building power, lighting losses caused utility power shutoffs, rolling blackouts, electrical equipment issues, and other environmental factors has generated increasing organizational safety and financial risks.  These prominent problems represent growing risks that continue expanding the need for reliable DC lighting solutions, especially for those facilities considered “critical” to our municipal infrastructures.  Connection of DC lighting directly to solar and/or battery creates instant insurance, resiliency, and measurable value measured by the offset of the renewables output directly to the lighting load.

Utility Incentives for Power to “Critical” Facilities

Electric utilities have spearheaded incentive programs for renewables that list "critical" which essentially prioritizes renewable applications for various facilities that are ideal for coupling with DC lighting. For example, the California’s Public Utility Commission’s Self-Generation Incentive Program (SGIP)offers rebates for installing energy storage technology at both residential and non-residential facilities.  “These storage technologies include battery storage systems that can function during a power outage…battery storage can be an important component of a more robust emergency preparedness plan in the event of a power outage.” 1

  • “Direct-Coupling” (DC-to-DC) DC LED lighting directly to solar and/or battery creates instant optimized value via strategic load sharing among the power sources. 
  • When added to solar & battery DC lighting catalyzes grid resiliency by empowering optimum security & power control with maximum load sharing possibilities for the lighting’s electric load. 
  • Direct-Connect (DC-to-DC) technology increases electric efficiencies upward of 15%, by eliminating the need for traditional  (inefficient) AC-to-DC conversions.

“Critical” Facilities for Low Voltage DC (LVDC) Lighting & Renewables

  • Police stations & fire stations;emergency response providers & ops centers; 911 call centers;
  • Medical facilities including hospitals; skilled nursing facilities & nursing homes;
  • Blood banks & health care facilities; dialysis centers & hospice facilities;
  • Public and private gas, electric, water, wastewater or flood control facilities;
  • Jails and prisons; independent living centers;
  • Cooling centers & homeless shelters supported by federal, state, local, or tribal governments;
  • Grocery stores, corner stores, markets & supermarkets, and food banks. 1

Link to CA Edison SGIP: https://www.cpuc.ca.gov/sgipinfo/ 1

Current and Trending Applications for Low Voltage DC (LVDC) LED Lighting (24DC, 48DC, 125DC)

  • Off-grid facilities
  • Utility substations & control rooms
  • Low voltage switchgear facilities
  • Modular buildings & structures
  • Agricultural structures (off-grid, including grow lights)
  • Commercial & Residential buildings with DC infrastructure
  • Solar PV / Battery Storage driven applications

“DC Lighting is Key to Optimized Microgrid Solutions” (Pacific Northwest National Laboratory)

Supported by the U.S. Department of Energy (DOE), Pacific Northwest National Laboratory (PNNL) conducted research to characterize the current state of DC lighting and building microgrid market and technologies. This research included extensive literature reviews, interviews of 28 subject matter experts and manufacturers…”

“Direct current (DC) electricity has the potential to improve the resiliency, reliability, and energy efficiency of building systems. DC facilitates the ability to more easily and directly connect renewable resources such as solar photovoltaics (PV) and energy storage batteries to DC building loads such as light-emitting diode (LED) lighting, computers and electronics, electric vehicle chargers, and variable-speed heating, ventilation, and air conditioning (HVAC) equipment.”

“The improved efficiency of the combined technologies can result in an estimated 10–18% in energy savings.  When configured as a microgrid, PV systems and batteries can power DC building loads in the event of a grid outage, improving the resiliency of homes and businesses. Despite the myriad benefits and opportunities provided by DC, its adoption in the market has been slowed by both the lack of available equipment and standards and the challenge of overcoming the status quo of building electrification.”

“PNNL’s research identified a growing market of available technologies along with significant potential benefits including energy savings, resiliency, reliability, and reduced costs. This paper explores the findings of this research and offers recommendations for stakeholders concerning moving forward with these beneficial technologies”: 2

Link to PNNL Study: https://www.pnnl.gov/publications/dc-lighting-and-building-microgrids  2

“DC lighting systems are well suited for use in emerging DC power transmission strategies…” - Emerging Technologies Coordinating Council (ETCC)

ETCC conducted a study to evaluate the electrical performance of commercially available DC lighting products for commercial interior lighting as compared to traditional AC lighting products…“DC lighting systems are well suited for use in emerging DC power transmission strategies, or DC Microgrids. DC Microgrids are capable of providing power directly from renewable resources to the appliance via an energy storage system, eliminating any AC-to-DC conversion losses.” 3

Link to ETAC Project: https://www.etcc-ca. com/reports/laboratory-evaluation 3

Sustainable Benefits & Value

DC lighting adds sustainable value to power infrastructures and microgrids, unlocking optimum security and power control by opening the door to strategic load sharing possibilities. “Direct Connection” of DC light fixtures to DC power sources (solar, battery) bypasses the need for inefficient AC-to-DC conversions hampered by traditional AC lighting, thus DC lighting offers greater efficiency and stability, plus other relevant benefits, including decreased carbon footprint and mitigation against risk of lighting loss due to power failure. The implications of DC lighting are enormous in the paradigm of building  power value, the growth of new and renewable technologies, and the positive economic, energy, and environmental impact yielded.  Here are ten (10) reasons why it just makes sense:

  1. Empower Grid Resiliency – DC lighting seamlessly connects to renewable DC power sources.
  2. Manage Risk – mitigate risk of lightingdowntime from power failures integrating battery storage and/or other DC sources (solar, wind), a DC-powered building lighting is safe-guarded against external environmental impact such as fires and (deliberate) power outages.
  3. Decrease Carbon Footprint – reduce carbon emissions equal to DC offset, enable zero energy objectives.
  4. Optimize Power Control & Costs – a DC lighting grid inherently empowers strategic load sharing options; integrating solar & battery storage with lighting can optimize power usage and costs by optimizing power consumption of the lighting system (and other systems, appliances) among DC power sources (i.e. solar & battery).
  5. Dependability & Stability – consistent, low noise, reduced flicker & noise circuit.
  6. Greater Efficiency – up to 15% more efficient, AC –to – DC inversions NOT required.
  7. Decrease Costs  DC LEDs yield cooler operations, reducing the potential building heat load, as well as offering higher efficiency and long lamp life.
  8. Convenience – low voltage wiring use vastly reduces material and labor cost for installation.
  9. Expandability – add DC devices and systems to create a smart network.
  10. Proven Technologies – many blue-chip companies and power utilities are currently using DC micro-grids.

Figure 1 – DC Lighting Diagram with Solar PV & Battery Storage

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