The IRP update takes into account the costs of the transmission networks associated with the energy mix.

The transmission network costs have been incorporated by including the estimated, direct transmission infrastructure costs, including collector station and substation costs in the total overnight generation technology costs. The costing was based on a high level estimate from recent Eskom average costs for transmission infrastructure.

For renewable energy technologies (like wind and solar PV), the transmission infrastructure costs entailed collector stations and the associated lines connecting to the main transmission substation, as well as the transmission substation costs. For conventional technologies, the costs entailed only the main transmission substation costs. Imported hydro and CSP transmission costs were treated the same as conventional technology costs.

The transmission infrastructure costs considered different capacity increments or penetration per technology in different parts of the country. Transmission corridor costs and ancillary costs required for network stability, particularly inertia, were not included as these are not directly associated with any technology but are part of strengthening the transmission backbone. A detailed transmission network costs report can be downloaded from the DMRE website (http://www.energy.gov.za/files/irp_frame.html).