Denmark generated 74% of its energy from renewable sources in 2017, making it a world leader in renewable power. But it's not the country's major energy providers that are driving this move away from fossil fuels. Rather, it is an increase in so-called "energy citizens" -- people that are decentralising the energy mix and installing smaller, renewable power projects. This is encouraged by government policies such as granting permits to wind projects only if the developers are at least 20 percent owned by local communities. It's not just Denmark -- across much of Europe energy citizens are playing an ever-more important role.