High Quality Content by WIKIPEDIA articles! A zero-carbon city is a settlement powered exclusively by renewable energy sources. To become a zero carbon city, an established modern city must collectively reduce emissions of greenhouse gases to zero and all practices that emit greenhouse gases must cease. Also, renewable energy must supersede other non-renewable energy sources and become the sole source of energy, so a zero-carbon city is a renewable-energy-economy city. This transition which includes decarbonising electricity (increasing the importance of the sources of renewable electricity) and zero-emission transport, is undertaken as a response to climate change and peak oil.