Microgrids and Energy Storage
Bernie Reinke May15
DOE’s definition of a microgrid
Microgrids are localized grids that can disconnect from the traditional grid to operate
autonomously and help mitigate grid disturbances to strengthen grid resilience.
Source: The Office of Electricity Delivery and Energy Reliability (OE)
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 and
that connects and
disconnects from such grid
to enable it to operate in
both grid-connected or
“island” mode.
A contemporary definition
A microgrid is a localized grouping of distributed electricity sources, loads, and storage
mechanisms which can operate both as part of the central grid or independently as an island.
A key requirement of a microgrid is to provide
improved reliability and security of power; a
seamless supply of local electricity.
Source: S&C Electric Company, Civicsolar, ZBB Energy
Microgrid domains
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Commercial
Community
Campus
Military
Remote
• Grid-tied utility distribution microgrids
• DC microgrids
Source: Navigant Research
Roles of energy storage
Storage smooths out fluctuations in the grid and
decouples generation and consumption
Matt Rogers, Executive Director, Energy Storage Association
http://www.marketwatch.com/story/these-are-teslas-main-rivals-in-energy-storage-2015-03-18
At the utility level:
• Renewable smoothing / firming
• Grid services – ancillary services, frequency regulation, voltage control
At the consumer level:
• Peak shaving
• Energy shifting
• Demand response
Benefits of energy storage
Benefits are typically characterised by
discharge duration and power rating
Technology types have differing value
contributions.
Source: EPRI Report, 1022261 Program 94, December 2010
Microgrid Implementations - Utility
• Focussed on grid ancillary services
• Traditional designs comprising rotational
generators only
• Strong focus now on accepting renewables
and coping with intermittency
– Smoothing - ramp control of very fast changes
– Firming – power at firm level over reasonable time
Ausnet Grid Energy Storage System
Source: Ausnet Services, Dr Yogendra Vashishtha RAPS Conf Mar15
King Island Off-Grid Power System
Ecoult 3MW/1.5MWh Battery
- Frequency Control
- Power response
- Block shifting – energy recovery
Source: Hydro Tasmania, Simon Gamble RAPS Conf Mar15
Microgrid Implementations - Consumer
Focussed on aspects to improve the continuity of supply
to the consumer, balanced with reducing demand and
usage charges
– Grid Backup – supply during grid outages
– Peak shaving – reducing energy demands from the grid during
peak periods when demand charges are the highest
– Energy shifting – moving excess energy from one timeslot to a
later timeslot (such as, moving solar produced midday to support the
evening peak)
– Demand response – responding to utility incentives to reduce
demands on the grid during specified periods
In most part, these requirements require multi-hour
energy storage solutions
UQ Global Change Institute
120kw/288kWh Redflow ZBM energy storage system, consisting of 36 Generation 2 ZBMs
and 24 SMA Sunny Boy 5kW inverters, installed in the basement, deployed 2013
GCI energy storage Objectives:
• Support the GCI 6-Star rating
• Renewables integration of
embedded 140kWp array
• Net-zero energy interaction
with the grid
Military FOBs
Raytheon RK30 and RK10 ESS, developed to
address military, off-grid and microgrid
applications:
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Comprising up to 12 ZBMs
Energy security
Diesel runtime reduction
Renewable integration
Independent assessment: Sandia National Labs: DOE
and Sprint
Telecomunication microgrids
Configurable to support grid or
off-grid connected sites
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Energy security, grid backup
Diesel runtime reduction
Renewable integration
Community Microgrid - LSB
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Completely packaged DC solution comprising up to 60 ZBMs – up
to 660kWh on a nominal 750VDC bus
Connectivity into industry-grade power electronics
MODBUS/HTTP communications for control, condition monitoring
and health alerts
Electrical configuration of batteries optimises string output
Applications in microgrid, renewables integration, industry, rural
and mining
AusIndustry co-funded prototype demonstrates 144kW 384 kWh
through an ABB inverter
Standalone power
Not strictly a microgrid relative to pure
definition, however …
Energy storage supporting remote sites
• Renewable generation
• Diesel runtime reduction
• Energy security