Microgrids Deliver Resiliency, Security and Savings
But interest is not confined to institutional settings, as businesses have started to investigate microgrids as well, particularly businesses that rely on a steady stream of electrical power. According to Asmus, they are “the ones who see what it costs when the grid goes down and they’re not selling their product–they actually have a quantified cost for that.”
Military installations are another type of facility that may require uninterrupted power. Smart Power Infrastructure Demonstration for Energy Reliability and Security—or SPIDERS—is a government program with the goal of improving security and energy efficiency at military bases. Along these lines, Asmus noted that “A lot of military bases historically would have separate diesel generators for each building so they would all be operating sort of independently burning more fuel than necessary.” A microgrid that integrated those resources could improve a base’s fuel consumption efficiency and resilience.
Components of a Microgrid
As the DoE definition states, the first requisite for a microgrid installation is an IoT-based infrastructure that can link external and local resources and provide overall control. Those resources are the external utility power grid and the devices that can produce electrical power residing on the organization’s premises.
Another requirement is a mechanism that allows the microgrid to connect/disconnect to/from the larger utility grid as needed. The microgrid and the utility grid are linked by a “point of common coupling” that maintains voltage at a constant level as provided by the utility until there is a problem on the utility’s grid that interrupts or otherwise affects service. In the case of an interruption, the response would be to disconnect and use the local generating capacity to provide power to the organization. If the incident was more of a fluctuation in utility power delivery, the microgrid would tap the on-site energy producers to even out the flow.
The on-site power resource may be any type of electrical generation apparatus, including conventional diesel- or gas-powered generators, although the trend is toward cleaner energy typically provided by solar or wind generation.
The microgrid’s infrastructure is a textbook IoT network; it’s a local network that uses a wired or wireless link to integrate the utility energy feed, local generating devices and consuming components. The two-way nature of the energy flow, with the microgrids site able to accept and rout utility power but also able to send excess locally produced energy back to the utility, requires specialized software to manage all the likely scenarios that involve buying and selling electrical energy.
“It’s very different from the sort of software that a utility would use to control the overall electrical grid because they’re usually not worried about controlling the loads themselves, they’re just trying to balance generation with consumption,” Brandt noted.
Most of the heavyweights in IoT-base energy systems such as Schneider Electric can offer microgrid components, but there are also smaller suppliers, often based in Silicon Valley, that provide microgrid products. The price of components as well as the long-term viability of the supplying companies are likely to be key considerations for new microgrid deployers.