We are developing a low-cost, solid-state hydrogen sensor to support the long-term goals of the Department of Energy (DOE) Hydrogen Program to encourage acceptance and commercialization of renewable energy-based technologies. Development of efficient production, storage, and utilization technologies brings with it the need to detect and pinpoint hydrogen leaks to protect people and equipment. The solid-state hydrogen sensor, developed at Oak Ridge National Laboratory (ORNL), is potentially well suited to meet cost and performance objectives for many of these applications. Under a cooperative research and development Agreement and license agreement, we are teaming with a private company, DCH Technology, Inc., to develop the sensor for specific market applications related to the use of hydrogen as an energy vector. This report describes our current efforts to optimize materials and sensor performance to reach the goals of low­ cost fabrication and suitability for relevant application areas.