Connected Deep: Infrastructure Innovations Driving Subsea Autonomy and Accuracy

Maximizing the efficiency and safety of subsea robotics demands more than just advanced underwater vehicles: it requires a support infrastructure. Universal charging will enable consistent power for future subsea-residency applications, while passive asset identification could improve accuracy in low- or no-visibility conditions. And as the domain of underwater robots expands, a proposed standardization of descriptions will help clarify the capabilities of the subsea fleet. Keeping subsea resident drones ready to operate requires keeping them powered up through subsea charging. One vision is for fully interoperable subsea charging locations so any underwater vehicle can land on the docking station to power up through wireless inductive charging technology. While presenting OTC 35570 at the Offshore Technology Conference (OTC) in Houston in May, Unplugged Chief Operating Officer Thomas J. J. Meyer compared such subsea docking stations (SDS) to land-based gas stations. “These charging stations are not so different from the ones you may find topside, not so different in the sense that any drone—any drone from any vendor—can land, dock, charge, and also communicate with the rest of the infrastructure, ” he said. Interoperable SDSs allow underwater intervention drones (UIDs) to remain stationed on the seabed, reducing the reliance on surface vessels and human intervention for launch or recovery of the unit for each mission. This approach reduces costs, improves safety, and reduces emissions. It also eliminates the need to wait out unfavorable sea-state conditions for robot deployment because the subsea vehicle is already stationed on the seabed. The authors suggest that where repeated missions are planned, or in situations where owned UIDs might be transferred across fields, placing an SDS on the seabed for a capital expenditure of 1 million to 2 million presents a compelling business case over repeated deployments of a remotely operated vehicle (ROV) or autonomous underwater vehicle (AUV) from a vessel. But deploying an interoperable SDS comes with challenges. Subsea units often feature proprietary docking and charging systems, making standardization difficult. Additionally, efficiently transferring power and data underwater remains a technical hurdle. These challenges are ones that operators like Equinor would like to see overcome. Equinor, with its numerous projects on the Norwegian Continental Shelf (NCS), has supported subsea residency efforts in the area. During two deployments, Saipem’s Hydrone-R was resident on Equinor’s Njord field for more than 8 months, completing a cumulative total of 240 days of continuous operations and more than 280 docking missions from an SDS. Currently, there are two other SDSs in place offshore Norway, with two additional installations planned and about a dozen more under consideration. In 2019, three SDSs were built and tested with different underwater vehicles. The Saab Seaeye Sabertooth AUV was used at the Saab test center in Sweden, while Saipem’s Hydrone-R UID was tested in Saipem’s test center in Italy. Oceaneering’s Freedom, Stinger Technology’s eponymous Stinger UID, and the M-series snake-shaped drone from Eelume were all tested at the Tau Autonomy Center near Stavanger, Norway.