Page 67 - Impiantistica Industriale - Novembre-Dicembre 2016

Introduction to microgrid

A microgrid refers to distributed energy resources and loads
that can be operated in a controlled, coordinated way; they
can be connected to the main power grid, operate in “is-
landed” mode or be completely off-grid.
Microgrids are low- or medium-voltage grids located at or
near the consumption sites. They can generate power from
both renewable and conventional sources and although
they are mainly electrical systems, they can also incorpo-
rate a thermal energy component, such as combined heat
and power. Microgrids are increasingly being equipped with
energy storage systems, as batteries become more cost
competitive. The system is controlled through a microgrid
controller incorporating demand-response so that demand can be matched to available supply in the safest and most
optimized manner. A flywheel or battery-based grid stabilizing system can be included to offer real and reactive power
support.
The concept of a microgrid is not new: the earliest electricity networks were essentially microgrids before they were
joined into regional and national grids. What is new is their changing and expanding role, in the face of rising power
demands, the falling cost of renewable sources, and the increasing need for supply resilience and autonomy – both
on- and off-grid.

Microgrids offer secure and reliable access to power, cost-effective and independent power supply and sustainable
and low carbon. They can be grid-connected or off grid. In the first case, microgrids can transition seamlessly to a
self-sustaining energy system, referred to as ‘islanded’ mode. Islanding can be applied in case of natural disasters, for
example, or when a microgrid is connected to a weak grid where recurring outages are supplemented with back-up
power. For critical loads this feature is key as it secures continuous operation. In addition to providing reliable power,
a microgrid connected to the main grid through a “point of common coupling”, enables import or export of electricity
as commercial or technical conditions dictate.
Off-grid microgrids are self-sustaining, autonomous energy systems that operate independently of the main grid.
Whether in rural communities, islands or remote industrial operations, ABB’s islanded microgrid solutions provide
access to grid-quality power in remote locations, typically at lower cost of electricity and with lower environmental
impact than conventional grids. Key advantages of this solution are that they can be deployed quickly and easily, even
in remote areas far away from the nearest grid connection point.

ABB inaugurates microgrid in South Africa

Zurich, Switzerland, June 8, 2016 – Innovative solar-diesel so-
lution provides continuity of power supply for ABB’s premises
in Johannesburg and helps reduce carbon emissions

Last June ABB commissioned an integrated solar-diesel mi-
crogrid installation at its 96,000 square meter Longmeadow
facility in Johannesburg, South Africa. This is a world premiere
for the innovative solution with fully grid-connected and off-
grid functionalities designed to maximize the use of renew-
able energy and ensure uninterrupted power supply to keep
the lights on and the factories running during any planned or
unplanned power outages on the main grid supply.
ABB has recently launched its flexible “plug and play” micro-
grid solution to boost use of renewables. It’s a a modular and scalable solution to address the globally growing de-
mand for flexible technology in the developing market for distributed power generation. The cost-efficient, containeri-
zed solution is relevant for mature and emerging countries and will help maximize the use of renewable energy sources
while reducing dependence on fossil fuels used by generator sets.
ABB is a pioneer and world leader in microgrid technology with more than 30 completed installations across a diverse
range of applications, serving remote communities, islands, utilities and industrial campuses. ABB’s comprehensive
microgrid offering includes consulting, design and engineering, supply, installation commissioning and lifecycle ser-
vices.

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