General Overview of Autonomous Forward-Deployed Systems and Their Energy Needs

Abstract

AbstractForward-deployed and remote sensor systems all require persistent, autonomous, reliable in situ sources of energy. There are several different classes of forward-deployed systems, each of which typically has a different range of energy requirements. Some of these systems are buoys; others are bottom-laid. Several such systems are being developed for a variety of scientific and military applications, including, for example, (1) remote systems with a single or small number of sensors; (2) networked scientific sensor systems (Undersea Distributed Networks); (3) low-power, forward-deployed surveillance systems with many sensors; and (4) forward-deployed communications relay systems. Energy requirements for these systems depend on several factors, including overall energy requirements, mission duration, duty cycle, observability, and fixed or mobile system. Many previous and current forward-deployed systems have depended on batteries for energy, but batteries are limited in the amount of energy they can store unless they can be recharged or replaced. Some previous systems have used diesel, sometimes in combination with solar panels and battery backups, but solar panels degrade and lose efficiency with salt encrustation, corrosion, and bird excrement. Recent developments in reliable, scalable wave energy technology, together with relatively efficient energy storage technologies, offer the opportunity for application of these technologies for providing autonomous power to remote sensor systems. This paper describes several remote sensor systems, reviews and summarizes energy requirements for these systems, and provides in situ wave energy system concepts to meet these requirements. The paper focuses on wave energy as being closest to practical implementation of current renewable energy technologies.