1. Saudi Arabia seeks $30bn–$50bn solar and wind energy investment. Financial Times (16 January 2017);
http://go.nature.com/2jVxIq6
2. Commission Proposes New Rules for Consumer Centred Clean Energy Transition (European Commission, 2016).
3. Directive 2009/28/EC of the European Parliament and of the Council (European Union, 2009).
4. Renewables could lose European power grid priority, documents reveal. The Guardian (1 November 2016);
http://go.nature.com/2k5sDOb
5. Obama, B. Science 355, 126–129 (2017).