defining terms -- microgrid

We've been using the term microgrid (among others) frequently and today
it came up again but with the thought it might also be applicable to
subsystems within the 'macrogrid'.   At the same time, in the Dutch
'microgrid' paper, they use the term Virtual Power Plant (not so much a
microgrid, but more of a role a microgrid may assume).  'Microgrid' is
used and defined differently by different entities and the definition
is evolving, as are most in this space, and new terms are devleoping. 
Perhaps it would be helpful to start a glossary for terms like these we
may use in the spec so everyone understands the definition as they are
used by EMIX?  The defining process may have the added value of
generating more clearly articulated scope and price communication
requirements.

For instance, below are several different defs/characteristics for
microgrid I've run across recently.  Each specs a different set of
characteristics from which we could generate an amalgam of those (and
any from other sources) characteristics most relevant to EMIX and
perhaps then define some use cases using these characteristics to drive
element declarations/definitions?

Just throwing this out, as an example, to start gathering glossary
terms.

-A

EI spec:

"Small, local versions of the bulk power grid that optimize the local
distribution system and may include local generation and storage.  A
microgrid may contain smaller microgrids and may be part of a larger
microgrid; communication interface at the edge of each microgrid is the
same."

http://eetd.lbl.gov/CERTS/pdf/mg-pesc04.pdf

Subsystem of generation and associated loads that can separate from the
distribution system to isolate from disturbances without harming the
transmission grid's integrity and providing higher local reliability by
islanding generation and load together.  Allows for local control of
distributed generation, eliminating the need for central dispatch.

From NAESB report to NIST

http://www.naesb.org/pdf4/interimsmartgridroadmapnistrestructure.pdf

"electric island"

From http://www.electricdistribution.ctc.com/microgrids.htm

A microgrid, a local energy network, offers integration of DER with
local electric loads, which can operate in parallel with the grid or in
an intentional island mode to provide a customized level of high
reliability and resilience to grid disturbances. This advanced,
integrated distribution system addresses the need for application in
locations with electric supply and/or delivery constraints, in remote
sites, and for protection of critical loads and economically sensitive
development.  By operating microgrid in the islanding mode, critical
loads can continue to operate, impervious to grid disturbance events.

http://certs.lbl.gov/certs-der-micro.html

CERTS Microgrid:

A key feature of a microgrid, is its ability, during a utility grid
disturbance, to separate and isolate itself from the utility seamlessly
with little or no disruption to the loads within the microgrid (e.g.,
in the CERTS Microgrid concept, no impacts on power quality). Then,
when the utility grid returns to normal, the microgrid automatically
resynchronizes and reconnects itself to the grid, in an equally
seamless fashion.  A critical feature of the CERTS Microgrid is its
presentation to the surrounding distribution grid as a single
self-controlled entity. A CERTS Microgrid appears to the grid as
indistinguishable from other customer sites that do not include DER.
This presentation means that the microgrid avoids many of the current
concerns associated with integrating DER, such as how many DER the
system can tolerate before their collective electrical impact begins to
create problems like excessive current flows into faults and voltage
fluctuations.   The peer-to-peer concept insures that no single
component, such as a master controller or a central storage unit, is
required for operation of the microgrid. Therefore, by its very design,
the CERTS Microgrid can continue operating with loss of an individual
component or generator.

From http://www.electricdistribution.ctc.com/microgrids.htm

http://www.electricdistribution.ctc.com/pdfs/Microgrid_Assessment_Phase_1.pdf
: (slide 4, also more detail at slides 9-11)

No clear definition, but characteristics include ability to operate
'islanded' or 'grid parallel', and to switch seamlessly between these
two modes, and to include significant DER capacity; driven by DER
technology rather than by energy service requirements.

http://green.venturebeat.com/2009/10/29/microgrids-a-21b-market-in-the-making/

Smaller-scale electrical systems spanning college campuses,
municipalities and business parks, where energy is generated, stored
and very closely managed on an intensely local level.  Without being
hooked into one of the larger national grids, there are less likely to
be disruptions due to peak demand or excessive power loads.  Easier to
do DR.  Can store enough energy to keep power flowing during blackouts
or other disruptions. This makes them ideal for emergency services,
hospitals, and of course, the military.