A Doctor of Mathematics and Oceanography, he invented a technology to convert energy in ocean waves into electricity,[2] also played professional rugby league, was a finalist in the Australian of the Year Award,[1] and in 2013 set a new world record for the Fastest Circumnavigation of the Earth on Foot.
While working at Newtown High, he attended UNSW part-time during 1988/89, obtaining a First Class Honours degree in Science.
[9] In 1997 he founded Energetech Australia which later became Oceanlinx and, during his spare time, began commercialising the wave energy technology he had earlier invented.
In late 2004, Denniss stood aside as the CEO of Energetech, but continued in the role of Chief Technology Officer of the company.
In 2005 he was invited by Jeffrey Sachs, Special Adviser to the UN Secretary General, to be a member of the Global Roundtable on Climate Change, serving on this forum until 2009.
[1] In Shenzhen, China, in 2009, his innovative technology was ranked third by the United Nations Industrial Development Organization (UNIDO) in its annual list of the Top Ten Renewable Energy Investment Opportunities in the World.