Background The largest radio frequency networks are designed for broadcasting television and radio services and for mobile communications. The success of mobile communications has boosted demand for denser and more sophisticated telecommunications networks. As a result, the number of relay stations for broadcast networks is now ten times greater that the number of telecommunication network sites. In the meantime, the switch from analogue to digital broadcasting has taken place. An increasing number of transmitting stations are installed in cities, leading to higher energy consumption, electromagnetic fields and visual pollution. As most countries intend to discard analogue television by 2015, a large number of frequencies will be freed-up to increase the capacity of telecom networks, especially in the UHF (ultra-high frequency) band. However, the environmental impact of the development of telecom and broadcast networks has not so far been sufficiently assessed. Objectives The LIFE ZENITTHYS project aims to drastically reduce the carbon footprint and other negative environmental impacts (visual and electromagnetic pollution) of telecom networks by developing an innovative hybrid transmission station concept that capitalises on recent advances in electronic devices, signal processing and renewable technologies. The project will build and test a 200-watt autonomous and low-greenhouse gas emitting hybrid base station that will be used for both high-definition television services and telecommunications high power relay. Its development will be a step towards more eco-friendly communication networks. Expected results: The project expects the following results: Reduction in the power consumption of the station by at least 40% (5.7 MWh/year); Energy supply to the station met entirely from renewable sources (wind turbine, solar panels). On the basis of 90 grammes of carbon dioxide per kilowatt hour, and the average annual CO2 emissions of a standard telecom station and a standard broadcast station (12 Mwh/year; 1.08 tonnes CO2/year), the hybrid station reduce greenhouse gas emissions by 0.567 tonnes CO2/year compared to standard facilities. The emissions would be reduced further by on-site production of renewable energy; Reduction of the electromagnetic and visual pollution (reduction of electromagnetic radiation from 60 to 0.6 volts per metre; replacement of macro base 3G antennae with smaller 4G stations); and Reduction in the number of transmitting antennae in cities by 50%.