emix — archive

[Anne Hendry <ahendry@pacbell.net>]

  
  


Considine, Toby (Campus Services IT) wrote, On 4/13/2010 7:28 AM:
49388A5276025649AC24AF97ADB9DA6256B0D25DCB@facmailmb3.facilities.unc.edu" type="cite">
  
  

  
  

  
A
Microgrid is merely an entity that actively manages its own energy use,
generation, storage, and market operations. A microgrid may choose, for
its own reasons to exclude any of those services from its active
portfolio. Similarly, it can add one of those services, say generation
or storage, without it being a concern to any other entities. We are,
of course, concerned with the market operations of the microgrid.
  

And where those market operations are exposed/traverse to
external/other grid(s), such as when a microgrid provides ancillary
services to external/other grid(s).

49388A5276025649AC24AF97ADB9DA6256B0D25DCB@facmailmb3.facilities.unc.edu" type="cite">
  

  

  

  
A
microgrid that participates in market operations must have a meter for
those operations. It is probable that a microgrid that participates in
both buying and selling should have a meter for each operation.
Logically, we should treat this as if it is true. Whether it is
actually true is beyond the scope of this TC. Whether the two meters
are virtual or not is beyond the scope of this TC.
  

  
A
microgrid can contain other microgrids, so a microgrid can support
internal market operations. For architecture purposes, the smart little
toaster that understands EMIX and EnergyInterop is a microgrid.
  

'Contain' still speaks to a hierarchical model.  Would it be necessary
for the toaster to be part of a larger centralized kitchen grid?  Or
can the devices participate in (micro)grid interactions in a
peer-to-peer scenario w/o having to go through a 'kitchen' controller?

49388A5276025649AC24AF97ADB9DA6256B0D25DCB@facmailmb3.facilities.unc.edu" type="cite">
  

  

  

  
Now, back
to the questions:
  

(fyi, not exactly questions, but a summary of contradictory views from
various sources on microgrids, in order to clarify the EMIX viewpoint
...)

49388A5276025649AC24AF97ADB9DA6256B0D25DCB@facmailmb3.facilities.unc.edu" type="cite">
  

  

  

  
1. architecture
  
   (some propose decentralized peer-to-peer
coordination,
  
    others expect centralized hierarchical
control)
  

  
A
Microgrid actively manages its own energy and uses market operations to
augment those resources. A microgrid can choose to outsource control of
any of its functions. It can choose to outsource them to its primary
energy supplier. Whether it chooses to do so is a separate business
process from its market operations.
  

Not sure how/why outsourcing comes into play (separate discussion), but
agree with your last statement.

49388A5276025649AC24AF97ADB9DA6256B0D25DCB@facmailmb3.facilities.unc.edu" type="cite">
  

  

  

  
2. two-way or one-way power flow
  
   (some proposed a single direction of power
flow,
  
    others proposed the microgrid for
ancillary services)
  

  
A
Microgrid that actively participates in both buying and selling is
effectively participating in two markets, or at least two market roles.
The market rules for each market role can be quite different. In some
markets, the rules for a role may happen to be too onerous to be
worthwhile. Market rules are outside the scope of the TC.
  

Great clarification.  Thanks.

49388A5276025649AC24AF97ADB9DA6256B0D25DCB@facmailmb3.facilities.unc.edu" type="cite">
  

  

  

  
3. size
  
   (some propose a microgrid should be less
than 1MW,
  
    others have no restrictions on generation
capacity)
  

  
Any
market rules about size and market participation are outside the scope
of the TC.
  

Yes.

49388A5276025649AC24AF97ADB9DA6256B0D25DCB@facmailmb3.facilities.unc.edu" type="cite">
  

  

  

  
4. connection points
  
   (some proposed only a single connection
point,
  
    others assumed more of a decentralized
integration/connectivity)
  

  
It
is a good practice to manage any critical supply chain for any critical
resource with an eye to redundancy. Having at least two suppliers is a
common requirement for many critical resources. Two (or more)
connection points is merely two (or more) supply chains. Even if the
counter-party for each supply chain is identical, the markets may be
different. For example, the two markets may be subject to different
capacity constraints, and so subject to different congestion pricing.
Some market rules for sellers may require locally produced energy
(which is effectively a limit on reselling electricity between
substations), but that is not unique to electricity. The local farmer’s
market has rules requiring participants to be original producers as
well. Such market rules are outside the scope of this TC.
  

Not sure.  Doesn't this speak directly to our current EMIX Element
'Market Context' then?

49388A5276025649AC24AF97ADB9DA6256B0D25DCB@facmailmb3.facilities.unc.edu" type="cite">
  

  

  

  

  
In
summary, I think the questions are a distraction,
  

Where out-of-scope we can discard.  There are related agreed-upon
(green) characteristics of microgrids of which a few must be relevant
enough to use as a definition of why/how microgrids warrant special
consideration (or if not, no need to have special mention in EMIX?).


Thanks -- appreciate your viewpoint and clarifications.


-Anne

49388A5276025649AC24AF97ADB9DA6256B0D25DCB@facmailmb3.facilities.unc.edu" type="cite">
  

  

  

  
tc
  

  

  

  

  
"If flies
are allowed to vote, how meaningful would a poll on what to have for
dinner be, and what would be on the menu?" -  Unknown
  

  

  

  
  

    

      

        

        
Toby
Considine
        
Chair,
OASIS oBIX Technical Committee

Co-Chair, OASIS Technical Advisory Board

Facilities Technology Office

University of North Carolina

Chapel Hill, NC
        
        

        
  
        
        

        
Email:
        Toby.Considine@ unc.edu

Phone: (919)962-9073 
        
http://www.oasis-open.org
        
        
blog:
www.NewDaedalus.com
        
      
    
  
  

  
  

  

  

  
From:
Holmberg, David [mailto:david.holmberg@nist.gov]

  Sent: Tuesday, April 13, 2010 9:52 AM

  To: ahendry@pacbell.net; emix@lists.oasis-open.org

  Subject: RE: [emix] Groups - microgrid_summary.pdf uploaded
  
  
  

  
To
your points, my comments:
  

  
1. architecture
  
   (some propose decentralized peer-to-peer
coordination, others expect centralized hierarchical control)
  
I
don’t think this matters to EMIX (or IMO to microgrid). What you do
inside your virtual end node (or whatever we are going to call it) is
up to you. EMIX is about getting you the price signal. Or does the
required signal somehow need to be different depending on your control
paradigm? I don’t see that.
  

  
2. two-way or one-way power flow
  
   (some proposed a single direction of power
flow,others proposed the microgrid for ancillary services)
  
EMIX
assumes 2-way is possible, whether you use it or not.
  

  
3. size
  
   (some propose a microgrid should be less
than 1MW, others have no restrictions on generation capacity)
  
This
is semantics about the term “microgrid”, nothing to do with EMIX,
unless we specifically use the term within the standard. I guess we
should not in any formal way. 
  

  
4. connection points
  
   (some proposed only a single connection
point, others assumed more of a decentralized integration/connectivity)
  
Do
you mean electrical connection or communication connection?
  

  
David