A side event, organised by the REN Alliance – a partnership of organisations representing the solar, wind, geothermal, hydropower and bioenergy sectors – sought to demonstrate the realities of 100% renewables at all scales.

It provided case studies of communities, cities, countries and regions, where various high-penetration combinations of renewable energy technologies are working together.

Technical solutions for a 100% renewable energy systems are in place today, along with the will to invest, and resource availability is plentiful from region to region, according to the REN Alliance.

International Solar Energy Society (ISES) president David Renne said: “The solar energy potential is vast. Working with other renewable energy technologies, it will provide an important component of 100% renewable energy systems.

“There is plenty of financial capital and public engagement available to support the transformation. We now just need the political will of national governments to create an effective policy and regulatory environment to drive us towards a 100% renewable energy future.”

World Wind Energy Association secretary general Stefan Gsanger said: “It is a great achievement of our work in the past that this COP21 for the very first time has a focus on renewable energy, and that many governments are supporting the call for a 100% renewable energy future. Of course such statements need to be followed by real action.

“Wind power can and will contribute a substantial share of the future energy supply. WWEA has identified a global wind potential of more than 100 TW, and we have analysed that by 2050, wind could provide 40% of the global power demand.”

International Geothermal Association executive director Marietta Sander said: “The COP21 Energy Day showed solutions, innovative practical case studies from around the world and examples of how strategic alliances can help to overcome knowledge gaps.”