MICROGRIDS ARE THE HOT NE W IDEA that’s been around forever. Thomas Edison’s first New York City power plants could be considered microgrids because those generating stations each acted independently from the others,
serving their own “islands” of connected loads. Like much of
the rest of our electrical systems, though, today’s versions are
becoming much smarter. With control systems that can disconnect and resync to larger connected distribution networks
almost instantaneously, microgrids offer both localized resilience and broader grid-support advantages for facilities and
The term “microgrid” has a broad and sometimes varying definition. For some, the presence of multiple generation resources
is an implied requirement, while others in the electrical industry aren’t as specific.
According to the Lawrence Berkeley National Laboratory,
Making yesterday’s technology smarter
“A microgrid is a group of interconnected loads and distributed
energy resources within clearly defined electrical boundaries
that acts as a single controllable entity with respect to the grid.
A microgrid can connect and disconnect from the grid to enable
it to operate in both grid-connected or island mode.”
For manufacturers and software developers, microgrid
applications can pose numerous questions. Put simply, there
are many microgrid markets, not just one. As Peter Asmus,
associate director for energy at Navigant Research, said, “The
challenge is that each segment is in a different level of maturity.”
Furthest along in maturity are those systems serving geo-
graphically isolated communities, including a number of
remote towns and villages in Alaska and several islands
around the world. In these settings, microgrids are more like
standard distribution networks because there is no larger
utility-grid connection. Primary power for such systems has
historically been diesel-fuel generators, though Asmus said
renewables, especially wind, have become more prevalent as
supplementary power sources. Reducing diesel dependence
can mean significantly cleaner operation and cuts in ongoing
“It’s become a more difficult engineering challenge,”
Asmus said, describing the technical requirements of con-
necting and managing a system with multiple generation
sources. “But it makes it more resilient. The challenge is how
you optimize the microgrid.”
That optimization has become easier over the last few
years as a number of traditional utility suppliers have begun
adapting products originally developed for larger transmission
and distribution systems. For example, Siemens has adapted
supervisory control and data acquisition (SCADA) controls
developed for utility-scale distribution systems in an offering
it calls “Spectrum Power Microgrid Management System.”
The company has repositioned an existing SCADA pack-
age to bring utility-scale capabilities for automatic islanding,
forecasting and optimization to campuses, military bases and
“Now, it’s just a matter of explaining it to the different marketplaces,” Wiedetz said.
Understanding many markets
Some electric utilities are interested in developing their own
microgrids to help strengthen weak points in distribution systems and, in some cases, teaming up with customers to enable
demand reductions and grid-support services. Also, the U.S.
military continues to push initiatives to make its bases more
sustainable and resilient.
These markets are driven by differing benefit hierarchies,
which all generally involve some arrangement of resilience,
renewables integration, cost reductions and income opportunities. For the military, resilience tops the list, but Wiedetz said
economics are less crucial.
Universities see sustainability and improving resilience as
drivers, along with the possibility of using campus installations
as teaching tools. For commercial and industrial facility managers, the selling point can be the opportunity to do more with the
fleet of backup generators they already have on hand.
“A microgrid allows them to maximize the value of the
investments they’ve already made,” Wiedetz said.
For example, adding controls enabling the islanding of
certain loads onto backup generation to reduce a facility’s
peak-demand charges—or loads during the local utility’s peak-
demand periods—could result in significant annual savings. S H