Description As the capacity demands for telecommunications continue to grow exponentially, the energy consumption of the network increases super-linearly with capacity. As a result, energy limits will constrain future growth, and this is predicted to be a significant brake on development of the global knowledge economy. The C-3PO project will develop a new generation of ‘coolerless’ and ‘colourless’ photonic components that will reduce power consumption, whilst enabling bandwidth growth and constraining cost. Taking a large modern internet data and switching centre with 5MWatt power consumption (44GWh/year) as an example, the ability of C-3PO photonic components to operate without cooling can lead to annual communications equipment and air-conditioning power savings of up to 4GWh, which will reduce energy costs by ~500k€/year for such a typical data centre. In addition, the C-3PO components will be ‘colourless’, or non-wavelength specific, which allows a single component type to operate at any wavelength in a dense wavelength division multiplexed (DWDM) system. As such, C-3PO technology can be universally applied from low-cost and reconfigurable router interfaces for metro networks down to the end-user optical modem in fibre to the home/business networks. In detail, C-3PO will develop low cost photonic-integrated multi-wavelength laser sources with high temperature-stable performance and use these as ‘optical wavelength power sources’ to seed colourless and coolerless InP-based reflective modulators driven by power-efficient SiGe BiCMOS electronics. This will remove the need for use of expensive, thermoelectrically cooled tuneable lasers, leading to projected global annual equipment savings of more than 300M€ from data and switching centre applications alone. This saving would be achieved through simplification of optical and electronic hardware, the reduction of the need for thermal management and the elimination of manufacturing costs associated with device characterisation and the generation of individual laser tuning maps. The presence of major European industrial players in the consortium will enable rapid commercialisation of the project outputs, enhancing European competitiveness in the global telecommunications market and ultimately leading to new high technology jobs for European workers.