Funds from this grant support the continuation and completion of work by an interdisciplinary team led by Granger Morgan at Carnegie Mellon University (CMU). The team is attempting to quantify the challenges and opportunities associated with transitioning the U.S. high-voltage electricity transmission system from alternating current (HVAC) to direct current (HVDC).  A transition to direct current has several potential advantages that could aid in decarbonizing the energy system.  For instance, direct current is more efficient than alternating current at transmitting significant quantities of electricity over long distances. That is important for the future viability of renewable energy technologies like wind and solar, where electricity, to be maximally useful, needs to be generated in windy or sunny locales and then transmitted over long distances.  Second, high voltage DC power lines can be sited alongside AC lines and sometimes in areas where AC lines cannot, thereby providing another tool to help advance clean electricity technologies. Using a method called expert elicitation, which asks subject matter experts to assess the likelihood of a range of factors associated with the technology’s development, the CMU team will closely examine the development of the novel power electronics technologies that are crucial to make the switch from HVAC to HVDC. This project will place a particular focus on the development of novel transistors, switching devices, and other power electronics necessary to advance HVDC lines. The result will be the identification of a set of well-informed parameters that can inform models designed to assess the likely costs and performance of a future HVDC system in the US.