VPS

The VPS is a platform that provides the Eskom System Operator (SO) with a means to optimally schedule all Eskom's controllable demand side resources. It presents the SO with a consolidated view of all available 'Negawatts' at any given time, along with cost profiles for dispatch, in much the same way as conventional power station scheduling.

The VPS provides a very effective mechanism for achieving peak shifting and in some cases peak removal, thereby improving overall system performance, decreasing the cost of capacity provision and postponing the need to build costly new generation capacity and/or network capacity. It provides the SO with a resource with similar characteristics to a peaking power station or many smaller widely distributed peaking stations.

The approach taken in creating the VPS was to make it indistinguishable from physical power stations from an operational (SO) point of view. Thus when additional load is needed because of an unexpected shortage or an expected peak, the SO can dispatch the VPS as he would perhaps an emergency or supplemental generator. This distributed 'Negawatt' generation is also the cleanest energy source available to the SO and can be deployed faster than any physical energy source of similar capacity.

Benefits of a Centralised VPS

• Provision of an efficient mechanism to dispatch 'Negawatts', thus enabling load shift from a broad customer base;
• A broad view of available load enables System Operators to make optimal scheduling decisions;
• Centralised bidding and customer contracting;
• Centralised planning, in emergency and time-ahead planning horizons;
• Centralised risk management and decision support;
• Centralised administration enables auditable and cost effective verification and settlement;
• Centralised operations and support, from participant bidding decision support, all the way through back-office operations and IT system support;
• The mechanism provides some competitive forces through the bidding process, thus ensuring cost effective load curtailment is achieved;
• A transparent process gives customers the assurance that they are not cross subsidising others through fair compensation across and within industries/customer groups;
• Improved system reliability.

VPS's Advantages over a Large, Individual Conventional Power Station

• Environmental benefits;
• Faster implementation time;
• The speed with which the VPS can modify its capacity and energy delivery curves;
• Effects of supply from a VPS are distributed, effectively reducing network constraints.

Greater real time control of the load is indispensable to the future of all utilities and saving energy to accommodate increasing demand is far more preferable to building new power stations. Projects such as the VPS world over are making headway towards achieving these ends. Thus the VPS has been designed and built such that integration into the current system is easy, with all the complexities of DR abstracted, yet all the associated advantages still accessible.

Download our Demand Response/VPS paper (0.65MB) and presentation (1.60MB) presented at the AMEU Conference in September 2011.

Download our DR-Pro product brochure (1.67MB).