In a stretch of desert north of Jeddah, experts at the King Abdullah University of Science and Technology (KAUST) have developed one of Saudi Arabia's burgeoning projects: a wastewater treatment plant designed to "purify and treat wastewater in an energy-neutral or if not energy-positive way," and an experimental farm that uses a product made from chicken manure, which they believe has the potential to transform the kingdom's desert into fertile land. But while the country is a major investor in climate tech, it has not abandoned its longstanding defence of oil, and critics say its gestures toward environmental friendliness offer only limited benefits. IMAGES AND SOUNDBITES