During David's twelve year tenure as CEO, NRG grew to be a Fortune 250 company, engaging in conventional power generation and competitive retail electricity services as well as being at the forefront of leading next-generation clean energy technology development. Prior to NRG, David was president and chief executive officer of International Power Plc, a London-based FTSE 100 company.

 David is a leading voice on climate change and the energy sector’s role in reducing greenhouse gas emissions having written extensively and spoken widely on the topic. He was an active member of the U.S. Climate Action Partnership from 2008 to 2011 and today is a B Team leader and member of the World Business Council for Sustainable Development.