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Subject: Re: [emix] defining terms -- microgrid

In addition to the link David Holmberg sent earlier, please see the 
following link for more information on Microgrids --

If the TC is interested, I can consider checking with LBNL Micro Grids 
expert, Chris Marnay, for a presentation at TC meeting.


Holmberg, David wrote:
> I don’t think I agree with any of the “interesting additions”, except 
> that every microgrid should have some storage to allow meeting typical 
> demand requirements. I’m not sure what “driven by DER” means. 
> Certainly there has to be some DER. The definition and value of high 
> reliability is in the eyes of the beholder.
> David
> *From:* Anne Hendry [mailto:ahendry@pacbell.net]
> *Sent:* Friday, March 19, 2010 2:59 PM
> *To:* emix@lists.oasis-open.org
> *Subject:* Re: [emix] defining terms -- microgrid
> Yes, the primary recurring attributes seem to be:
> - can operate independently from grid or in parallel
> - can seamlessly move from one mode to the other
> - independently controlled at the local level, no need for central control
> - driven by DER, co-locates generation and load
> - highly reliable
> Interesting additional notes from the survey presentation at the same 
> site are the 'points of varying agreement'
> - generation capacity must be < 1 KW
> - must contain > 1 generation source
> - must connect to the grid at a single point
> - must contain storage (batteries, etc)
> - must be able to meet full load requirement
> -A
> Holmberg, David wrote:
> They all agree as far as I can tell. I like the 
> http://www.electricdistribution.ctc.com/microgrids.htm, along with the 
> EI idea of hierarchy put together.
> David
> *From:* Anne Hendry [mailto:ahendry@pacbell.net]
> *Sent:* Friday, March 19, 2010 2:49 AM
> *To:* emix@lists.oasis-open.org <mailto:emix@lists.oasis-open.org>
> *Subject:* [emix] 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.

Rish Ghatikar
Lawrence Berkeley National Laboratory
1 Cyclotron Road, MS: 90-3111, Berkeley, CA 94720
GGhatikar@lbl.gov | +1 510.486.6768 | +1 510.486.4089 [fax]

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