RE: [energyinterop] Real_time Price Message Line 525 spec wd-08

["Jeremy Roberts" <jeremy@lonmark.org>]

Thanks for the information, Ed; it's quite helpful. 

So, today (at least where I live in PECO's territory of southeast Pennsylvania), utilities are allowed to send you a paper bill that includes a little notice that the rates went up and are retroactive.  To me, an ex-post increase in price is unacceptable.  If LonMark were to bill our members for dues and then tell them in that same bill that we raised the cost of membership retroactively, they'd all cease to be members. 

In the DR sense, where the range of cost/kWh is expected to be $0.05 to over $1.00 in some cases (in a DR project I worked on around 1994, the prices were capped at $0.50), the total cost to a consumer for an ex-post measured period could be quite high.  How can we protect the consumer with/from ex-post pricing in our models?  I'll be mobile until our call later today, so please share your thoughts with me then, if you would. 

- Jeremy 
 
Jeremy J. ROBERTS 
Technical Director 
LonMark International 

-----Original Message-----
From: ed@cazalet.com [mailto:ed@cazalet.com] 
Sent: Tuesday, March 16, 2010 1:36 PM
To: energyinterop@lists.oasis-open.org
Subject: [energyinterop] Real_time Price Message Line 525 spec wd-08

Initial thoughts on defining real-time price messages at line 527 of draft spec wd-08. - Ed Cazalet 3-16-10
We have defined real-time price as a price for any amount of energy.  Forward prices and forward transactions are also to be defined, but this note focuses only on real-time price and transactions.
Real time prices can be defined for any interval of time.  60 minutes, 15 minutes, and 5 minutes are typical interval lengths for real-time prices. However, as technology improves, real-time intervals can be the shortest interval that can be read by a meter.  For example, I have been told that the meters now being installed by PG&E will provide readings on six second intervals over the home area network, but intervals of 15 min will be typical for backhaul to the utility.
A real-time price is typically ex-ante or ex-post.  An ex-ante price is a price quoted to the customer before the real-time interval. An ex-post price is a price known to the customer after the interval is passed.  An ex-post price has the advantage to the supplier in that she will know amount purchased before a price is set.  An ex-ante price quote has the advantage to the customer that she will know the price before deciding how much to buy.
In fact both ex-ante and ex-post prices can be used.  In this case the a quantity is transacted at the ex-ante price and any difference between the meter quantity and the transacted quantity is priced at the ex-post price.