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Subject: RE: EMIX Product and Time - Answers and Suggestions needed
I just had a long conversation with Ed on some of his issues and concerns. One set of them centers on the use of the word Product throughout the specification. As it is now, There is a Product Description and a Product. A product is defined as a Description applied to a [WS-Calendar] Sequence. Ed feels this is confusing, and he convince me that it is as well. Let’s call it a Banana. Let’s say that we have a Product Description and a Banana. A banana is a Product Description applied to a Sequence. The Banana may be used to in a Tender. A Banana may be proffered as a resource into a bid. A Banana may be schedule for Generation. A Banana may be a report of Energy Usage coming back from a metering point. Calling all those Bananas “Product” causes confusion. A Banana may be a single interval of time, with the Product Description, Duration, Price, and Quantity fully specified. A Banana may be a load shape over a series of intervals, sharing a Product Description, and a common Duration, although the Quantity varies for each Interval. A Banana may be a representation of an hourly pricing tariff, sharing a Product Description, and a common Duration (hour), with a Price that varies for each Interval; no quantity is specified. This comes to the question: What do we call a Banana? Only sometimes is it what we normally call a Product. Ed suggested that we call it a Packaged Product (or productPackage). We also decided to throw it before the TC. A Product Description applied to a Sequence is called a:_____________ tc "If something is not worth doing, it`s not worth doing well" - Peter Drucker
From: Toby Considine [mailto:Toby.Considine@gmail.com] Excellent question, Ed. The real question, underneath, has to do with ramps, and perhaps with my understanding of them (which is getting better, now). I had a concept of a ramp interval, i.e., an interval during which power varied but all other aspects were constant. This required me to have an interval with a (Begin power / end power) as opposed to a “normal” interval which had a single power. As at that time, all quantities were in the interval, and this was external to the product (resources had not really come together then), I needed another way to handle it. What I did at the time was sub-class the EMIX interval, itself an instance of a WS-Calendar Interval, into an interval that was either constant or ramp power. This sub-class, then, with a choice if ramp or constant, can exist anywhere a an EMIX interval does, which includes as any member of an EMIX Sequence. So, it is not really an additional interval, but a redefinition for use in Power. The CIM handles this by having “steps” of constant power instead. It then deals with the predicted variance between actual power and stepped power by having a market rule requiring the resource to “make good” on the difference with spot purchases. I was concerned that such tacit “everyone knows how this works” assumptions break down as we move into common definitions for generation resources, distributed resources, and distributed generation. A key goal is to make all the tacit assumptions explicit in the interfaces, a goal as strong as that of hiding unnecessary technical detail. The use of ramp rates in Resources has perhaps reduced the need for such intervals, meaning perhaps we can fall back to the un-elaborated, un-redefined bare emix sequence. If not, as your question indicates, then the Power Sequence warrants a couple paragraphs, perhaps in Chapter 5, as it is an underpinning structure throughout the other Power-based interfaces. As always, we need to support the present and the future, rather than perfect the past. A good quick discussion? Sean? Donna? Bruce? Phil? Ruchi? Brian? Bill S? Each of you has chimed in on aspects of this subject. tc "If something is not worth doing, it`s not worth doing well" - Peter Drucker
From: Ed Cazalet [mailto:ed@cazalet.com] See attached. Edward G. Cazalet, Ph.D. 101 First Street, Suite 552 Los Altos, CA 94022 650-949-5274 cell: 408-621-2772 |
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