emix — archive

[Toby Considine <toby.considine@fac.unc.edu>]

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.
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.
Now, back to the questions:
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.
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.
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.
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.
In summary, I think the questions are a distraction,
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