Modular Grid-Connected Microgrids in Weeks – Duke Energy Demonstration Project Update

Greentech Media recently updated progress on the “world’s first modular microgrid.” Okay, not sure that the description of “world’s first” is accurate, but the idea that a major investor-owned utility is exploring ways in which microgrids can connect to and island from the grid is definitely newsworthy. After a year of planning, the actually building of the demonstration and test microgrid took place in only three months.

The Mount Holly microgrid project is focused on the nitty issues that grid-connected microgrids face – microgrid optimization, unscheduled islanding transition, and island-to-grid connected transition. Solving the technical issues in grid-connected microgrids are critical to the market blooming. Optimizing in real time involves balancing maximizing solar and storage while, in this case, not being allowed to push any power back to the grid (this was solved with a resistive load bank that can absorb up to 500 kW at a time). Getting things wrong could damage equipment or lead to an outage, so the ability to test the system in a test setting is critical. The system is able to island and support the load without interruptions, but there were issues at first, related to synchronization of the inverters that had to step in and continue to supply AC current to replace grid power.

If you are interested in grid-connected microgrids, I recommend that you check out how the HOMER software can help with optimization issues related to grid outages. HOMER’s unreliable grid capabilities will let you play with an infinite world of possibilities before you get started.

Meanwhile, it’s interesting watching the microgrid market line up in the United States and other places where the grid has been a very reliable source of electricity for well over 100 years.