Facing historic challenges over the next 20 years in helping to guide an estimated $2 trillion in investment to renew or replace aging infrastructure, ensure environmental compliance and adopt smart-grid technologies, U.S. regulators should take a new approach to managing the risks of both the costs of new infrastructure and the time it takes to install it, suggests a new report from the sustainability think-tank Ceres.

The lowest risks and costs will be provided by expanding investment in clean energy and energy efficiency, while the highest risks attach to placing too many bets on conventional generation technologies, according to the 60-page report.