As global population growth, economic development and technological advances continue to ramp up, the demand for sustainable and renewable energy supply and devices is emerging as one of the most critical and challenging issues of modern society. The 3rd International Symposium on Renewable Energy Technologies (ISRET) was organized by the Centre for Clean Environment and Energy (CCEE) and Griffith University and held at the beautiful Gold Coast in Australia, from 19th to 22nd July 2019. The 3rd ISRET brought together top scientists to discuss the latest advances in functional materials for sustainable energy conversion and storage technologies with the aim to promote international cooperation and partnership between world leaders in the fields of nanomaterials for clean energy applications. A total of 106 impressive oral presentations were delivered with notable plenary and keynote lectures given by Australian, American and Chinese academicians. Specific topics covered in the symposium include low dimensional nanomaterial design and developments, photocatalysts and photoelectrochemical devices for solar fuel production and environment, semiconductor materials for new generation solar cells, electrode materials for efficient energy storage systems including batteries and supercapacitors, new nanomaterials for electrocatalysis and fuel cell applications, magnetic materials for energy conversion and storage systems, computational nanomaterial science, etc.