\label{fig:lumi} Instantaneous luminosity, in units of $10^{34}~\cms$, expected at TLEP (purple line) at each interaction point, as a function of the centre-of-mass energies. For illustration, the luminosities expected at linear colliders, ILC (blue line) and CLIC (green line), are indicated in the same graph. For TLEP, the luminosity at each interaction point is determined in the configuration with four interaction points operating simultaneously. As explained in the text, it would increase significantly if fewer interaction points were considered. The red line indicates the TLEP luminosity summed over the four interaction points. 