Upcoming EMI changes due to wind offer arrangements project

  • Last post 10 September 2019
Phil Bishop posted this 09 September 2019

On 19 September 2019, the manner in which wind plant is offered into the wholesale market will change. See also Transpower's WOA page. The wind offer project will cause a few things on EMI to also change:

Final pricing SPD case files

Several new fields related to wind offers in both SPD input and output files will appear. See the Tranpower WOA page for the precise details.

Final pricing GDX files

The vSPD GDX files that we generate from the final pricing SPD case files, and publish on EMI, will have two new fields:

  • i_IsPriceResponse is a 0/1 flag indicating whether the constraint containing i_PotentialMW is to be used for a particular offer. 
  • i_PotentialMW is the potential megawatts available form the offered wind plant. Note that i_PotentialMW is a new set element in the parameter called i_tradePeriodOfferParameter. The computation of i_PotentialMW uses the so-called Forecast of Generation Potential (FOGP), a new value that forms part of the offers made by the traders offering wind generation into the wholesale market. For generators that have IsPriceResponsiveIG = 1, the IGPotentialMW acts as a cap on scheduled capacity and scheduled generation. For RTD, RTP and FP schedules, this will be based on FOGP and actual output; for all other schedule types this will be FOGP (what SPD calls IsPriceResponsiveIG and IGPotentialMW, vSPD calls i_IsPriceResponse and i_PotentialMW , respectively.)   

Offer stack reports

For the next few months, our offer stacks will be slightly off when it comes to the megawatts of wind generation offered. This is because the report is powered by a database that will be decommissioned in the near future, and we are not modifying that database to take account of the new parameters appearing in the SPD case files. This ommission will be rectified when we port the offer stack report on EMI over to the replacement database. We will have more to say about this nearer to the time that the revised offer stack report goes live.

Offer data

The file of offers that we publish each day will soon contain the new Forecast of Generation Potential (FOGP) parameter, but it won't be ready by 19 September. We are still working through the change request process to make this happen. When we get it up and running, we will make further announcements on this forum and will run the old and the new side by side for a few weeks.


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NigelCByron posted this 09 September 2019

Hi Phil

When you say "Offer data - ....  will run the old and the new side by side for a few weeks." , how will this be done ? Different file names ?  We currently capture *Cleared_Offers.csv

Earliest possible advice of configuration change and sample file would be appreciated for our own Change Process !

Please confirm the following will not be affected












Phil Bishop posted this 10 September 2019

Hi Nigel - as I noted above, when we get the information together I'll let you know the precise details. You will get plenty of time to change your process. The paths you listed have nothing to do with wind offers and will not be impacted.