No AC, Just DC

Washington's Microgrids

By Cutright Elizabeth on May 31, 2016 in News

By eliminating the need to convert DC electricity to AC voltage for commercial and residential use, a new generation of Microgrids is set to upend the traditional energy infrastructure.

While Edison beat Tesla in the first go-around, the latest battle of the voltage could have an entirely different outcome. Alternative power sources and smart fixtures provide much of the fodder for energy efficiency strategies, but one elephant in the room is AC/DC conversion. Currently, AC/DC conversion results in a 20% energy loss, not insignificant when you consider residential and commercial buildings consume 65% of all energy generated. By eliminating that conversion loss, DC microgrids are poised to significantly impact energy use and generation both in the US and internationally.

Clean and Lean

The benefits associated with DC microgrids include lower energy losses and an increase in utilization of onsite generation. DC microgrids are also more reliable and resilient, continuing to run unabated even as the grid goes down and power outages run rampant. And because DC microgrids ease the incorporation of onsite solar (and perhaps, someday, wind), there’s a significant reduction in greenhouse gas emissions and carbon footprint.

Not only can DC microgrids improve energy efficiency and reduce reliance on the grid, they can also help buildings meet net zero energy standards. At the November 2015 Greenbuild Expo in Washington DC, the Net Zero Energy Pavilion highlighted many microgrid technologies. Completely solar powered, the pavilion’s photovoltaic panels connected directly to the building’s lighting and appliances in a powerful representation of DC microgrid potential.

Work and Play

Not only does the incorporation of DC microgrids improve energy efficiency, they provide greater resource management. By enabling partial (if not total) decoupling from the grid, DC microgrids allow building managers and residents to exert more control over where they get their energy, and how they deploy their resources throughout their facility. As a result, tenants and owners can use less energy without trading performance for frugality.

In the past, DC microgrid installation had to overcome several hurdles, including price and the lack of basic rules and installation procedures. California non-profit Emerge Alliance aims to bring regulation to the industry by “developing standards leading to the rapid adoption of DC power distribution in commercial buildings.” The Alliance has already begun to develop protocols and guidelines designed to facility the implementation of these DC microgrids so that they can be both flexible and interface easily with the building’s existing infrastructure.

Local Power Plays

Not only are the implications of this flexibility significant for many industrialized countries, DC microgrids also have the potential to help the developing world access clean, inexpensive and environmentally-neutral power. At a time when both India and China are experiencing a booming middle class and ever-growing industrialization, power production choices have the potential to influence the environment on a global scale. DC microgrids could go a long way towards mitigating the environmental effects of rising energy consumption in in the developing world.

“DC microgrids are going to be applicable globally because they will solve problems in countries with similar issues and will also help developed countries use this technology more broadly,” Sri Chandrasekaran, the IEEE director of standards and technology in India office explains in an interview with The Institute.

“AC is not going to vanish anytime soon,” Chandrasekaran continues. “We need to understand how these hybrid systems will work together… Those technologies are still evolving, and I think they will play a key role not only here in India but also throughout the world.”

Writing for IEEE Spectrum, Rajendra Sighn and Krishna Shenai quickly lay out the ways in with DC microgrids could bring the virtues of local electricity to the developing world.

“With the decreasing cost of electricity generated by photovoltaics and wind turbines, DC microgrids may be the most efficacious way to provide electrical energy to those who have none,” they begin.

“Just as cellphone use in the developing world exploded without the prior installation of landlines, DC microgrids could leapfrog over the traditional system of centralized AC generation,” they conclude.

“The market for microgrids in the developing world could be huge, and the benefits they would bring to what are now grossly underserved regions are monumental.”

Behold the Enernet

While many still dream of coast-to-coast smart grid able to intuitively mange power generation and delivery, widespread adoption of microgrids – especially DC microgrids – may well mimic the rapid advances of both Internet and the latest deluge of tech disruptors like Uber and Airbnb.

As former CEO of NRG Homes Scott Mcbee declared to Microgrid Media, “The creators of Uber didn’t come from the transportation sector, and the founders of Airbnb didn’t come from the hospitality industry. It’s unlikely that whoever launches a leading energy 2.0 company will have a traditional energy background.”

Backing Mcbee’s assertion, Brian T. Patterson, President of the EMerge Alliance, explains in a guest column for gb&d Magazine, “Connecting power creation to power consumption in a true mesh network of massively distributed local building microgrids would give us the power of an ‘Enernet’ or electric energy network.”