3 Reasons Why DC Microgrids Will Replace The US Power Grid
August 4, 2021
To understand why the U.S. doesn’t already use the better DC microgrid system over the AC national power grid system, we’ll take a glimpse at the history of AC vs. DC power and then look at how DC microgrids are the power systems of the future.
The Current Dilemma: AC vs DC Power
In 1878, Thomas Edison had the idea of providing electric lighting directly into buildings using incandescent lighting running on direct current. In 1882 he carried out this idea when he built the first commercial power station to provide electricity to residential buildings and businesses in the close area.
His power stations were the primary source of lighting for buildings until 1886 when George Westinghouse built the first commercial AC power station. AC then began to take off when Edison’s electricity rival, Nikola Tesla, developed his AC induction motor in 1888 which would be licensed by Westinghouse in the same year.
With AC power having the ability to transform to higher voltages, buildings could now be powered from farther distances for a lower price in comparison to DC power. With this advantage Westinghouse’s AC power would become the universal system used in the U.S. and cemented in 1892 when Edison left the electric power business.
Mass AC Adoption
Throughout the early 20th century more AC power stations and transmission lines would be placed throughout the United States leading to the creation of large regional AC power grids that are still used to this day over 100 years later. With the quick and universal adoption of AC infrastructure, DC power and localized power grids were left behind. However, in light of recent power grid failures across the country, governments and communities are looking for a more sustainable, reliable, and locally integrative solution for power needs. This has driven the market to take a renewed look at the DC microgrid as a power solution.
What is a DC Microgrid?
A DC microgrid is a localized power system that can run independent of the main power grid by generating and utilizing its own DC power. The most common ways of generating power for DC microgrids are with solar panels, fuel cells, and wind turbines with any excess energy stored in batteries. Conveniently, all these pieces of a DC microgrid store or generate DC power making it immediately compatible with computers, phones, LEDs, and most other end devices.
3 Benefits of a DC Microgrid
From a sustainability perspective, DC microgrids provide a more eco-friendly impact than the AC power grid. One aspect of a DC microgrid that allows for improved sustainability is the autonomy of the power system. By being able to control the generation, distribution, and usage of power, building owners can pursue their sustainability objectives with more flexibility.
With control over power generation, building owners can decide to use solar panels or wind turbines to produce clean and renewable DC power instead of relying on power plants miles away that are most likely burning fossil fuels to produce power.
Using a DC microgrid, power generation is localized, minimizing energy losses from transmission lines by around 6% decreasing overall emissions to produce energy. Additionally, because these sources are natively DC producing and end devices are typically DC receptive, the DC microgrid can forgo some AC/DC or DC/AC conversions which cause around a 10% efficiency loss each.
A DC microgrid is a necessary layer to provide reliable power to facilities and buildings. One defining capability that makes the DC microgrid extremely useful is its capability to island, which means that it can disconnect from the main power grid and run local loads by itself. This capability is typically used in emergencies when disasters or weather take down the main power grid. Take Tohoku Fukushi University for example. During the 2011 earthquake and tsunami that took down the city’s power grid for weeks, the university stayed powered because its DC microgrid was able to island.
In addition to its ability to island, DC microgrids are also more resilient than the current AC infrastructure. With the current AC infrastructure there are thousands of miles that are not properly weatherized. This was one of the biggest reasons for the costliest power grid failure and disaster in Texas history. However, a DC microgrid, being a smaller structure, can be weatherized properly to be more resilient to severe weather or disasters.
A DC microgrid integrates perfectly to power a smart building. As companies are increasingly focused on providing work environments that improve employee productivity, health, and wellness, smart buildings have become the emerging solution. Within these smart buildings there are many sensors, lights, screens, and other IoT enabled devices that work together to improve the workplace. In order to distribute power and data to connect these devices a PoE infrastructure can be put in place. With PoE’s low voltage DC nature, the perfect way to generate power is with a DC microgrid because it’s a fully DC process and can forgo unnecessary AC/DC conversions within a building.
Another integration of a DC microgrid is its ability to become a part of the smart building. By connecting power generators to a smart building platform, facilities managers will be able to efficiently distribute power to devices minimizing unnecessary energy usage. A facilities manager will also be able to monitor the power generation of the DC microgrid, allowing smarter energy decisions in accordance with building and company energy objectives.
A Look into the Future, Now
DC Microgrids are not theoretical solutions for the future. In fact, many buildings are only a step away from implementing them. The closest is the first all-digital hotel, The Sinclair. The Sinclair is a smart hotel with a complete PoE infrastructure that distributes DC power throughout the building to power lights, screens, and many other devices. The building is also the first hotel to implement a lithium-ion battery pack as a backup source of power. With a DC PoE infrastructure, DC powered end devices, and DC battery storage, the last addition for it to be considered a DC microgrid would be DC power generators like solar panels.
With the current power infrastructure aging and becoming more vulnerable, the question isn’t if an issue will arise, it is when an issue will arise. Given this high risk, it is time to create plans of actions for how buildings and people will be powered for the future. With benefits for the earth, buildings, and humanity around the globe, it is apparent that the DC microgrid is the foundation for powering the world in the future.