The Moroccan city of Ouarzazate is used to big productions. On the edge of the Sahara desert and the centre of the north African country’s ‘Ouallywood’ film industry it has played host to big-budget location shots in Lawrence of Arabia, The Mummy, The Living Daylights and even Game of Thrones. Now the trading city, nicknamed the ‘door of the desert’, is the centre for another blockbuster – a complex of four linked solar mega-plants that,…