Beginner’s Guide to DC Microgrids
Interest in DC microgrids is on the rise as more businesses are looking for innovative and efficient ways to meet increasingly critical power challenges. Companies want to reduce their use of hydrocarbons and nation states are increasingly looking to minimise their dependency on energy supplied by politically unaligned neighbours.
One part of a solution to this problem is the deployment of DC microgrids. The worldwide microgrid market in 2020 was valued at over $6 billion USD and is projected to grow to $33.4 USD by 2027. This includes AC, hybrid and DC microgrids. But what is a DC microgrid and why might your company consider deploying one?
What is a DC Microgrid?
Simply put, a DC microgrid is a localised power system that utilises Direct Current (DC) to generate, store and/or distribute power.
A DC microgrid takes the concept of a national power grid, scales it down to meet site requirements, and uses DC rather than Alternating Current (AC) to create energy efficiencies.
A DC microgrid can be:
- run independently of the national (AC) power grid, generating, storing, and transporting its own renewable DC energy, or
- a grid-connected system, where the incoming AC power supply supports some (or all) of the power provision required, where the AC current is centrally converted to DC before distribution across the microgrid.
A DC microgrid differs from a traditional power infrastructure. Traditionally, AC power is delivered from the national grid, distributed as AC across the site to each connected device, with distributed AC to DC power conversions then performed at the device as required. Conversions are often required for a significant proportion of connected devices across a site. This is because the vast majority of modern devices (from laptops to LED lights) require DC power.
Why are DC Microgrids Uncommon?
It’s a matter of History.
In the late 19th century, during what became known as the “War of the Currents”, two different methods for electric power delivery were developed: alternating current (AC) and direct current (DC).
Thomas Edison first demonstrated his DC power system in 1882 at Pearl Street Station in New York to power the light bulbs he had developed several years earlier. The electrical current in his DC power system flowed in a single direction. This provided a method to distribute power at a very consistent voltage within a restricted area, like single buildings or small city blocks but was not easily converted into higher or lower voltages.
In 1886, an AC system was demonstrated by the Westinghouse Electric Company and Nicola Tesla as a complete power system. The AC power system alternated the flow of electrical currents. This allowed simple transformers to be used for conversion to higher or lower voltages – useful for transmission of power over longer distances.
Early electrical devices (e.g. incandescent light bulbs and motors) could be operated using either AC or DC, so this was not a major consideration.
At this time, both systems competed for mass adoption. Following a winning bid to power the Chicago World’s Fair in 1893, the Westinghouse Electric company was awarded licences for the AC system to generate and supply power to the entire city of Buffalo, New York, and later this became the dominant power delivery method in the USA and thereafter, the world.
Today AC remains the global standard for national-scale power distribution. However, the growth in ‘solid state’ electronics, which require dc not ac, makes DC the dominant requirement in both domestic and commercial settings. this has been one factor behind the resurgence of interest in DC power.
What are the Benefits of a DC Microgrid?
There are several key reasons innovative businesses are looking at DC microgrids as power delivery options for commercial building sectors, including logistics, entertainment, hospitality sites, offices, university or hospital campuses and more. These include:
- Significant increase in energy efficiency, meaning reduced cost and carbon footprint
- Fewer conversion devices increases performance and reliability and further reduces cost
- Centralised battery storage (batteries being DC devices) acting as one single site-wide backup facility
- Inclusion of PV (a DC generation technique)
- Together, operation in ‘island mode’, removes reliance on the national grid and allows the DC microgrids to be completely self-sufficient
Who Should Consider Deploying a DC Microgrid?
DC microgrid deployments can be delivered on a wide range of different campus and building projects and configured to meet the specific requirements of each site. They can be designed alongside conventional AC systems to meet the energy distribution needs of sites such as large industrial buildings, sports stadia and hospitals. With significant financial, environmental, efficiency and reliability benefits, DC microgrids are also highly compatible with onsite renewable energy generation and battery storage, offering further cost and sustainability advantages.
Interested in DC Microgrid Compatible Technologies for Logistics Sites?
Take a look at the article here.
DC Microgrid Live Case Case Studies
Honda Distribution Centre, California
In 2018, the largest commercial DC microgrid in the US went live at the Honda Motor Distribution Centre in Chino, California. Solar energy is generated onsite and then distributed via the DC microgrid to LED lighting, ventilation systems and forklift vehicle charging, with other loads being supplied from the microgrid. The system incorporates battery storage providing backup and optimising the use of renewable energy generated on site.
Green Data Centre AG, Switzerland
Data centres have embraced the use of DC microgrids to run the most demanding computing resources for several years. An example of a large data centre that has deployed this technology is the Green Data Center AG in Switzerland. Some of the key benefits that have been published include a 10% improvement in energy efficiency, 15% lower investment costs and 25% less space required for electrical equipment. Increased reliability of the equipment and reduced maintenance costs are also highlighted as important benefits.
Landways’ DC Microgrids, UK
Landways has designed, built, and continues to operate two live DC microgrids in the UK. The DC microgrids, retro-fitted into high-density stadium environments, successfully support the power requirements of the mission-critical technology systems, including market-leading surveillance camera, high-performance audio and Wi-Fi.
The Adams Park project, home to Wycombe Wanderers football club, is a 26,000m2 campus with a 9,500 stadium capacity. The project, completed during the 2020-21 Covid pandemic, was Landways’ first live DC microgrid project, the result of three years of pioneering design innovation in power delivery and distribution.
Completed shortly thereafter at Gloucester Rugby’s Kingsholm Stadium, a new digital audio project provided Landways an opportunity to deploy its DC microgrid system alongside the previously installed full-fibre network on the 25,000m2, 16,100 capacity stadium.
Landways’ DC microgrids deliver cost and energy efficiencies for these customers, helping to combat the increasing costs of grid-supplied electricity and also providing a 3-hour battery backup for critical systems, replacing the previous use of diesel generators. In the event of a power failure, all the supported systems can operate for a typical event with the DC microgrid and onsite battery system in island mode.
The digital and power infrastructure in these projects have been deployed using Landways’ patent-pending Induct™ solution (Patent Application: GB2592955 (A) ― 2021-09-15), offering further benefits to customers including full-fibre connectivity, minimal deployment disruption, streamlined technology upgrades and simple additions of new technology systems.
Think a DC microgrid might be useful for your business?
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