The inside of today’s energy systems host some of the harshest environments anywhere on the planet, and the faults, fractures, and carbon dioxide plumes deep underground present an array of challenges for resource recovery. Sophisticated sensors help energy systems to operate more efficiently, and assist in recovering underground oil and gas. However, creating sensors that can withstand these formidable environments is a challenge. NETL is on the task. Sensors are detectors that can measure physical quantities like temperature and pressure. The sensors convert measurements into a signal that communicates with an electronic device that is read by operators who take actions to adjust conditions if necessary.