Stopping climate change and averting its worst impacts requires an urgent and dramatic reduction in the greenhouse gas emissions emitted from our energy system. This in turn necessitates a rapid transition away from high-carbon energy sources like fossil fuels, nuclear power, agrofuels and industrial biomass. At the same time, we need an urgent effort to expand energy access and affordability so as to provide everyone in the world with affordable and reliable energy to meet their basic needs. All of this points to a massive new-build programme to roll out low-carbon renewable energy technologies like on- and offshore wind, tidal and solar energy.