There is a dual challenge of meeting increasing global energy demand alongside an urgent need for transition to clean energy sources. Despite major progress in renewables, fossil fuel use has actually increased in recent years. Instead of thinking solely about an energy transition, we might look for "energy addition" opportunities—adding in new sources of breakthrough renewable technologies like nuclear fission, fusion, and geothermal for new demand. What's the catch? The development required to scale these novel cleantech projects to commercial viability requires significant investment. Promising tech in a lab can often hit the dreaded "Valley of Death", the point where increased risk and uncertainty is a major barrier to commercial deployment. Here's where financial engineering comes in, like deploying mega funds and adopting phased development models akin to biotech. These strategies can de-risk and attract the critical investment needed to get us through the Valley of Death and into a much more sustainable future. Andrew W. Lo is the Charles E. and Susan T. Harris Professor, a Professor of Finance, and the Director of the Laboratory for Financial Engineering at the MIT Sloan School of Management.Lo's current research spans four areas: evolutionary models of investor behavior and adaptive markets, artificial intelligence and financial technology, healthcare finance, and impact investing. He has co-founded several asset management and biotech companies, and sits on the boards of several for-profit and non-profit public and private healthcare organizations.Lo holds a BA in economics from Yale University and an AM and PhD in economics from Harvard University. This talk was given at a TEDx event using the TED conference format but independently organized by a local community. Learn more at https://www.ted.com/tedx