EMIX 1.0 and the OASIS Smart Grid Suite of Standards Version 1.0
Committee Note 01
06 June 2012
William Cox (firstname.lastname@example.org), Individual
Edward Cazalet (email@example.com), Individual
William Cox (firstname.lastname@example.org), Individual
Edward Cazalet (email@example.com), Individual
We describe how EMIX relates to other OASIS Standards, including WS-Calendar, Energy Interoperation, Emergency Management, SOA Reference Model, and Security standards.
This document was last revised or approved by the OASIS Energy Market Information Exchange (eMIX) TC on the above date. The level of approval is also listed above. Check the “Latest version” location noted above for possible later revisions of this document.
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EMIX 1.0 and the OASIS Smart Grid Suite of Standards
Version 1.0. 06 June 2012. OASIS Committee Note 01.
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We describe how EMIX [EMIX] relates to the OASIS suite of Smart Grid Standards, WS-Calendar [WS-Calendar], Energy Interoperation [EnergyInteroperation], as well as other OASIS Standards including Emergency Management [REF NEEDED], SOA Reference Model [SOA-RM], and Security standards.
EMIX is an information model for energy and market information, which is in turn used by Energy Interoperation services for communicating price and product information. Understanding the relationship of the three standards helps in understanding the OASIS Smart Grid suite of standards.
To more effectively understand and use EMIX, one must start with a broad understanding of OASIS WS-Calendar [WS-Calendar] schedules to which price and product information is attached. We then describe how OASIS Energy Interoperation [EnergyInteroperation] and its OpenADR 2 profile uses both EMIX and WS-Calendar.
Composing relatively simple standards has significant advantages over building large unitary standards. The OASIS suite of Smart Grid Standards is designed for composition and re-use, and in fact composes with each other and with other specifications and technologies as we describe in Section 2.
OASIS Energy Market Information Exchange [EMIX] Version 1.0. Latest version.
OASIS Energy Interoperation Version 1.0. Latest version.
OASIS Reference Model for Service Oriented Architecture Version 1.0, 12 October 2006. OASIS Standard. http://docs.oasis-open.org/soa-rm/v1.0/soa-rm.html
OASIS WS-Calendar Version 1.0, 30 July 2011. OASIS Committee Specification. http://docs.oasis-open.org/ws-calendar/ws-calendar-spec/v1.0/cs01/ws-calendar-spec-v1.0-cs01.pdf
Collaborative Energy Status Page, Various Dates, http://collaborate.nist.gov/twiki-sggrid/bin/view/SmartGrid/CollaborativeEnergyStatus
OASIS Emergency Management Technical Committee, http://www.oasis-open.org/committees/emergency/
EMIX Issues Page, http://collaborate.nist.gov/twiki-sggrid/bin/view/SmartGrid/EMIXissuesPage
Slides for Priority Action Plan 09, July 2011. http://collaborate.nist.gov/twiki-sggrid/pub/SmartGrid/PAP09DRDER/PAP09_OpenSG_20110719.pptx
We focus on the suite of OASIS Smart Grid standards. The three standards respond to three of the National Institute of Science and Technology [NIST] Priority Action Plans [PAPs], and have been implemented so as to address interoperation requirements across and within domains of the Smart Grid.
The OASIS Smart Grid suite consists of three standards. The first two are pure information models, expressed as an XML vocabulary for describing information in their scope; the third is an information model, architecture, and set of Web services definitions for communicating among participants in the Smart Grid.
The relationships of these three standards and a family of seed standards for energy usage information can be seen in Figure 1.
Figure 1 Dependency graph for EMIX, Energy Interoperation, and WS-Calendar
As shown, EMIX uses WS-Calendar and is in turn used by Energy Interoperation. Energy Interoperation and EMIX use the minimal subset of the NAESB Energy Usage information. The arrows indicate that Energy Interoperation uses both EMIX and WS-Calendar, while EMIX uses only WS-Calendar.
The following sections describe how the specifications are used and use other specifications.
The WS-Calendar and Energy Market Information Exchange (EMIX) specifications are both information models, expressed as XML vocabularies. WS-Calendar uses and extends the IETF iCalendar standards, which are the common information model and vocabulary for calendaring and scheduling. The [WS-Calendar] specification was joint work between the North American Energy Standards Board [NAESB] and the Calendaring and Scheduling Consortium.
WS-Calendar uses Sequences of time Intervals to communicate schedules. Information elements that are unique to an Interval are communicated in the Interval, while information elements common to the entire Sequence are factored out and communicated once with the Sequence.
For example, the start time of the Sequence, and a common duration of each Interval might be communicated once with the Sequence (in a WS-Calendar artifact called a Gluon), while price information might vary across the Intervals and be contained within each Interval.
In WS-Calendar, a Gluon relates to a Sequence by relating to a specific Designated Interval within that Sequence. All other Intervals have defined temporal relationships, directly or indirectly, to the Designated Interval. If a Gluon contains a start date and time, that start date and time is inherited only by a single Designated Interval; the start dates and times for all other Intervals in the Sequence can be computed from that single date and time. This allows scheduling of an entire set of time-related intervals, a Sequence, with one operation rather than changing each interval’s start, end, and/or duration.
EMIX uses the common terminology of markets. EMIX expresses schedules for energy use, delivery, curtailment, and demand with the WS-Calendar vocabulary for schedules, and provides the EMIX vocabulary for expressing information on price and product definition. These definitions are used by implementers and by other standards.
EMIX extends WS-Calendar Intervals and Gluons, attaching price, quantity, product definitions, and more. In the EMIX information model, Interval Duration and the Product Description, Price, and Quantity for each Interval in a Sequence can each be inherited from a Gluon. This follows and extends the rules of inheritance defined in WS-Calendar.
Figure 2 below provides a model demonstrating a sequence of three Intervals, and the successive application of Gluons to bring them to market.
Figure 2 EMIX Schedule and Building a Product (from [EMIX] Section 6.4)
OASIS Energy Interoperation [EnergyInteroperation] uses the WS-Calendar and Energy Market Information Exchange (EMIX) information models to implement demand-response, distributed energy resource interactions, and transactive energy interactions.
For Events, information may consist of curtailment or generation or regulation levels, quantities, or prices. The price expression is simplified from EMIX.
Energy Interoperation defines interactions for conveying price quotes (such as clearing prices in a market) and tenders (such as offers to buy or sell) by conveying EMIX schedules with energy product information.
In addition several information items in Energy Interoperation build on EMIX definitions. These include
The OASIS Smart Grid Suite of Standards are defined to be composed as part of palette of standards used in an application environment, and also to have other standards composed with them.
For example, price and product information may be commercially sensitive. Following the compositional approach for electronic commerce and eBusiness standards, a deployment using EMIX will define and compose the necessary security standards to achieve the deployment business and security goals.
Likewise, the messages containing EMIX price and product information may travel on a variety of transports and with a variety of reliability, privacy, assured delivery, and non-repudiation standards and technologies that depend on the business and security goals of the deployment.
By defining information models that can be exchanged with any security and reliability, uses of EMIX in any environment can share code, information model, XML schema, and the understanding of energy products achieved through broad public discussion and review.
In this section we list several OASIS Standards used by or coordinated with by EMIX.
OASIS Emergency Management Standards—EMIX uses the same profile of the Open Geospatial Consortium’s GML. This allows, for example, an area affected by a power outage to be communicated in the same way to emergency management service.
OASIS Energy Interoperation—Useful capabilities are enabled by the GML geospatial definitions that are possible in EMIX. Prices may be described for an area of coverage of a particular feeder or substation, and with OASIS Energy Interoperation a curtailment event could be called on that area, or Distributed Energy Resources may be called on.
OASIS Security Standards—The industry-standard OASIS security standards can be composed with EMIX, WS-Calendar, and Energy Interoperation, tailoring security to the requirements for an interaction or a piece of information.
OASIS Message Reliability Standards—The industry-standard OASIS message reliability standards can be used to send and receive EMIX price and product information in Energy Interoperation messages or whatever messaging standards one selects.
EMIX is part of a suite of Smart Grid Standards under development by OASIS. By standardizing the description of energy schedules and product attributes, EMIX provides a means for exchanging information among different domains of the Smart Grid and among participants with different business and information models.
The following individuals have participated in the creation of this specification and are gratefully acknowledged:
Edward Cazalet, Individual
Toby Considine, University of North Carolina
William Cox, Individual
David Holmberg, National Institute of Standards and Technology
Based on contributed notes by TC members
13 October 2011
Rewrite based on review and comments
 See the NIST Smart Grid Framework and Roadmap at http://nist.gov/smartgrid/upload/FinalSGDoc2010019-corr010411-2.pdf and the Smart Grid Interoperability Panel Priority Action Plans at http://collaborate.nist.gov/twiki-sggrid/bin/view/SmartGrid/PriorityActionPlans
 Only the Designated Interval inherits the Start Date and Time.