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MicroGrids & Energy Storage
Distributed Generation
Interconnection Workshops
MICHAEL SHEEHAN, PE
FAILTE GROUP
MARCH 2015
MicroGrid Architecture
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•Three Categories of MicroGrid Architectures
– Discrete load facility (Data Centers, Critical Load
– University or Hospital Campus
– An islandable portion of a larger distribution system (Southend
of Whidbey Island or North Bend WA)
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•Design Goals
–Increase reliability and power quality for critical areas of the
grid and critical loads
–Ideal if integrated with the Grid and wholesale markets
–Should facilitate the integration of variable energy resources to
the greatest extent possible
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What is a MicroGrid?
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Utility Grid Disconnect MicroGrid
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MicroGrid Stability
Generation = Load
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Variable Resources Require More
Balancing
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Load = Generation
In order to maintain 60 Hz on system
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Renewables are intermittent and variable
•Cannot be relied upon by themselves to follow
load
•Load changes Quickly – at flick of a switch
•Generator do not load follow instantly
Diesels are fastest load followers
Traditionally diesels provide fastest response
Storage is faster and maybe a better choice
Analogy Hybrid Auto
•Today’s paradigm: Traditional architecture
•Diesels are fastest gen choice for Microgrids
•Tomorrow’s reality: Storage - Generator hybrid
•Works same way as hybrid vehicles
•Generator will cycle less – better efficiency
•Generator can be more efficient design slower
•Better efficiency = lower fuel consumption emissions
•Less generator cycling = longer life
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Energy Storage and
Ancillary Services
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Advanced MicroGrid Concept
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MicroGrid Commercial Industrial
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Benefits of MicroGrids
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Reliability
• Power quality control inside the MicroGrid is what differentiates it. In
new MicroGrid installations, modern power-electronic devices are
used for switching and control and the prevention of backflow of
power during periods of low voltage, under frequency or outages on
the main grid. Power generation and load inside the MicroGrid are
automatically balanced without loads being affected.
• During normal times the MicroGrid presents itself as a controllable
generation and load even though internally it may be supporting
intermittent resources, but if needed, the MicroGrid EMS can
implement separation, islanding and reconnection to the grid
seamlessly with no flicker
Energy Storage and
Uninterruptable Power Source (UPS)
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How a UPS Works to Solve Grid Events
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Battery Cost
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Possible MicroGrid Paradigm
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Ergon Energy Battery Storage
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Ergon Energy's plan to install network-scale battery storage in 2015 has
been praised by peak distribution body Energy Networks Association
(ENA), and used in a case study by Accenture Strategy in a recent
report which looks at the challenges facing the Australian electricity
sector.
Ergon officially announced its intention to install 20 Grid Utility Support
Systems (GUSS) on its Single Wire Earth Return (SWER) network in October
this year. The announcement has been well received as using battery
storage on this scale to improve load voltages and overall reliability to
our customers in the more remote parts of our network will be a national
first.
Marine Corp Twentynine Palms
Single Line Diagram
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Storage Example:
Arbitrage has difficult economics today
Ameren: Taum Sauk, Missouri,
440MW re-commissioned May, 2010
Storage Application:
Peak Shaving—TOU Rates
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Storage Application
Frequency Regulation --- PJM
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PJM Performance Frequency
Scores by Resource Type (Jan ,13)
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