IEEE Electrification Magazine - March 2014 - 3

demand-side management is growing, commercial sector generation is
growing, and analysts are projecting
double-digit annual growth rates for
microgrids. this suggests two things:
1) the traditional approach to providing electric services is being challenged from within and 2) consumers
are actively seeking alternatives for
their electric services.
having established that the industry is changing, do microgrids fit into
this new electric service for a digital
economy? Do microgrids measure up
to the consumer's objectives of reliability, resiliency, cost savings, and
emissions reduction?
are microgrids reliable? Lessons
from the cadre of microgrids operating today, as well as the lessons from
highly automated distribution networks around the world, suggest that
microgrid reliability is on the order of
99.999-99.9999% uptime (commonly
referred to as "5-nines" and "6-nines"
reliability). this is compared to the
u.s. grid at 3-nines and the european
grid at 4-nines reliability. in comparison, data centers design for 7-nines
or greater reliability. Properly designed microgrids improve reliability
for their customers.
are microgrids resilient? the lessons from superstorm sandy in 2012
in the northeastern united states
demonstrated that microgrids are
resilient to major events that challenge the grid. all of the known
microgrids in Maryland, new Jersey,
new york, and Connecticut operated
through the storm and its aftermath.
some became safe havens for displaced citizens as the region struggled to recover from sandy. our
favorite example is the Brevoort in
Manhattan. the Brevoort is a 20-story
private residence with 700 residents,
but that number increased to 1,500
for several days. it is important to
note that a grid outage is not merely
an inconvenience to some. some of
the residents in the Brevoort are
retired and physically challenged.
the loss of electricity to the elevator

in a tall building can isolate some
reduced. thermal efficiencies for cenresidents from food and medical
tral-station generation range from 33
assistance. in interviews with the
to 60%, while small ChP thermal effiBrevoort residents, the continued
ciencies used in microgrids are combuilding services were often menmonly above 80%. My experience with
tioned as necessities to sustain life.
microgrids to date regarding emission
are microgrids economical? some
reductions is that it is highly depenmicrogrids operating today are ecodent upon the consumer's objectives.
nomical, and some are focused on
In This Issue
reliability improvements without ecoin this issue, you will find interesting
nomic considerations. however, as
articles about various aspects of the
the industry matures, technology
maturing of microgrids as an electric
costs will decrease, new business
service tool. the seven articles and one
models will emerge, and designs
column included in this special issue
will be refined. this will create
are outlined as follows.
more economical mithe "technology
crogrids in the near
Some microgrids
Leaders" column by
future. our experioperating today
John McDonald states
ence in designing 22
are economical, and
that many stakeholdmicrogrids to date is
ers are optimistic that
that microgrids besome are focused
the fundamental
tween 2 and 40 Mw
on reliability
strengths of the techare more economical
improvements
nology and its myriad
than being a 100%
without economic
applications will precustomer of the grid,
vail over what appear
and this is without
considerations.
to be surmountable
monetizing the relihurdles for microgrids.
ability and resiliency
But to move beyond the hype, the techbenefits. Many of the microgrids in
nology's drivers and opportunities
the northeast that continued to opershould be spelled out alongside
ate through sandy and its aftermath
an honest review of the barriers to
were built for cost-saving reasons. the
implementation. McDonald defines
microgrids received resiliency as an
microgrids in general terms and deadditional benefit. Microgrids are not
scribes some typical use cases. he
universally economical compared to
then describes the recent efforts by the
the grid as an electric service, but
state of Minnesota to explore mithere are many regions with abovecrogrid drivers, opportunities, hurdles,
average electricity rates, demand
and next steps. the discussion is relecharges, and fixed infrastructure
vant to not only Minnesota's interest
charges that create the economic enin microgrids but to other states, utilivironment for microgrids to flourish.
ties, and microgrid sponsors.
as microgrids mature as a technolothe first article is by asmus, who
gy/business solution, the cost of impoints out that microgrids are moving
plementation and operation will
into the mainstream. he states that
decrease, making more regions ecothe future development of the u.s.
nomically viable with time.
grid will require the safe and economDo microgrids reduce emissions?
ical operation of the high-voltage
some do when the consumer's objecmeshed transmission grid since it is a
tives include environmental goals.
us$800-billion asset that is fully
when microgrids include renewables,
amortized. yet, the fundamental
emissions are reduced. also, when
architecture of today's electricity grid,
microgrids include high thermal effiwhich is based on the idea of a topciency combined heat and power
down radial transmission system
(ChP) resources, emissions are
IEEE Electrific ation Magazine / MARCH 2 0 1 4

Table of Contents for the Digital Edition of IEEE Electrification Magazine - March 2014