Cooperative Living February 2017 - 26

CloserLook | by Paul Wesslund, Contributing Writer
Coming Soon: Designer Electric Grids
A
In the future, microgrids will meet local priorities for reliability, security and sustainability.
new way of thinking about electric
utilities could make your electric
service greener and better able to
weather power outages.
The idea is microgrids - small, local
systems of electric service that are
connected to the larger, national electric
transmission and distribution grid, but
also capable of operating independently
from the grid.
" How we deliver electricity is changing, "
says Tom Lovas, a technical liaison and
consultant with the National Rural Electric
Cooperative Association (NRECA). " We
have to think differently in how we
operate the system. "
This future described in a 2014 NRECA
report as a " grid of grids " would use new
technology and innovative ways of
organizing the system of power lines to
accommodate renewable energy, improve
efficiency and security, and keep power
flowing in natural disasters.
" Many futurists envision a grid built of
smaller, independent or quasi-independent
generating entities such as microgrids, "
says the report, " Achieving a Resilient and
Agile Grid. "
" Change is necessary, and there is now
an explosive growth in the tools that will
allow us to manage the grid with more
agility and precision. "
120 MICROGRIDS AND GROWING
A good way to understand microgrids
is to imagine a small island, just off the
mainland, with a few additional wires
and power controls. Here's what those
additions might do:
* Connect essential services like hospitals
and gas stations to backup generators;
* Wire together banks of solar cells and
wind turbines, and large-scale batteries,
to provide power even at night or when
the wind is not blowing -- or when the
grid fails;
* Control the flow of electricity among
power sources like local rooftop solar
panels, distant power plants or even
neighboring towns so it is used most
efficiently.
And that's not pie in the sky. One energy
firm estimates there are more than 120
24 | Cooperative Living | February 2017
microgrids in the U.S., another 100 on the
drawing board, and that it's a market
expected to grow 13 percent every year for
the next 10 years.
But those numbers could be too small,
because a microgrid can mean a lot of
different things. While a microgrid is often
thought of as a collection of homes,
businesses and generating sources, it could
be as small as a single house, depending
on your definition. What microgrids have
in common is that each is an electric
system connected to the nationwide grid
that can also operate on its own.
" Any shared load of a single resource
could be considered a microgrid, " says
Lovas. It could be a military base that
needs to always have power without fail,
or a manufacturing plant installing a bank
of solar cells next door for a supply of
more environmentally friendly energy.
" A single generator that serves two
houses would be a microgrid, " says Lovas.
" There are a lot of different definitions of
what a microgrid really is. "
Electric cooperatives are among the
utility groups studying how to make the
best use of this innovation.
" At NRECA, we're looking at microgrids
as a way to enhance reliability and
resiliency, particularly for operating of
critical requirements, " says Lovas. " In fact,
for years we've had microgrids, in a way,
by having emergency generators provided
for hospitals and other critical facilities. "
To understand microgrid development,
it helps to know about two bits of jargon
used by the people making the plans -
both are mentioned in the title of the 2014
NRECA report.
One is " resilient. " The report explains
the term as different from " reliable. "
Reliability, says the report, refers to the
goal of keeping the lights on all the time. A
resilient system, on the other hand, is one
that can bounce back quickly after a major
outage. The objective in that case might
be to recognize that power might be out
for several days, so there needs to be a
system in place that can provide backup
electricity immediately for hospitals, gas
stations and pharmacies.
Last fall, the National Governor's
Association recommended that states
consider microgrids, as part of a report
on how to avoid some of the hardships
caused by natural disasters like 2012's
Hurricane Sandy.
FRIENDLY TO RENEWABLE ENERGY
The other term the microgrid planners
use is " agile. " That refers to the ability of a
utility system to handle new situations,
like interest in renewable energy that
might lead a homeowner to install a bank
of solar cells on the roof and want to sell
the excess electricity back to the utility.
In fact, one of the motivators for
development of microgrids is the increasing
use of renewable energy, which is expected
to quadruple by 2020. Microgrids could
push that progress even faster.
Among the roadblocks to renewable
energy is the fact that solar doesn't work at
night and wind won't work in calm
weather. But as battery technology
improves, a microgrid could connect all of
the parts to store the renewable energy.
As Lovas explains, " While we can
have a microgrid based on renewable
resources, it really becomes even more
effective as energy storage becomes more
readily available. "
Microgrid thinkers are preparing for the
future by planning ways to standardize
designs so the " grid of grids " can be built
more efficiently, and so that microgrids can
connect to each other through the larger
grid. They're developing computer
software for automatic operation both
inside a microgrid and outside with other
electricity sources and users. They're
writing safety standards, recognizing that
with more generators on the system, there
will likely be more two-way flows of
electricity along the wires, making it
especially important to keep track of when
lines are energized. They're even planning
for higher levels of electronic security as
computer hackers spread software bugs. ■
Paul Wesslund writes on cooperative issues for the
National Rural Electric Cooperative Association,
the Arlington, Virginia-based service arm of the
nation's 900-plus consumer-owned, not-for-profit
electric cooperatives.
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Cooperative Living February 2017

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