vSPD stands for vectorised Scheduling, Pricing and Dispatch. The vSPD model is a precise replica of SPD. It is written and solved using the GAMS software and is based on the published SPD formulation.
vSPD takes advantage of the computational efficiency of modern linear programming and mixed integer programming solvers by vectorising many SPD schedules prior to solving. Vectorisation involves reformulating the sequential and independent problems as a single optimization, requiring just a single solve operation. In the case of ex post pricing, prior to the advent of real-time pricing on 1 November 2022, this meant that all 48 trading periods from a single day were solved as a single optimization. With real-time pricing, there are typically about 250 SPD schedules that give rise to dispatch prices spanning the 48 trading periods of each day. These are comprised of real-time dispatch and price-responsive schedules and are similarly vectorised to be solved as a single optimization.
The input data for vSPD is provided in the form of GDX files. Daily GDX files for use in vSPD can be found here or, for dates prior to the advent of real-time pricing, here.
vSPD output is generated as a collection of GDX and CSV files that report on the key model outputs such as generation, prices, branch flows and reserves. Some inputs to the model, for example load, are also included in the output reports.
vSPD is regularly audited by the same independent auditors contracted by the system operator to audit SPD each time a change to the SPD formulation is implemented.
The most recent audit of vSPD was undertaken in August 2019 by Robinson Bowmaker Paul (RBP). The RBP approach to testing and their statement of vSPD's fitness for use are explained in the vSPD certificate of compliance.
vSPD v3.0.4 certificate of compliance.pdf (PDF, 75 KB)
Last updated: 29 August 2019
Development of vSPD follows that of SPD – each time a change is made to SPD, an equivalent change is made to vSPD. Consequently, soon after vSPD has been audited, it is likely to be modified. At all times, however, vSPD will replicate SPD for all published schedules. vSPD will next be audited in 2024.
The implementation of real-time pricing on 1 November 2022 has caused us to sever backward compatibility of vSPD versions.
Version 3.1.0 is the last version of vSPD that we released prior to real-time pricing. It will work with all GDX files up to and including 31 October 2022.
We will no longer publish the zip file for the most recent version of vSPD on this page, as it is always available to download from our vSPD GitHub repository – the most recent version will be at the top of the list. As of 11 December 2023, the most recent vSPD version is 5.0.2.