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Offshore renewables reach for robotics

Robots have long been used by the offshore oil and gas sector to reduce the costs of installing facilities and operations and maintenance. The offshore renewables sector is starting to benefit from the technology, which could help it make significant cost savings if certain technical hurdles can be overcome

The offshore renewables sector is beginning to use robots in similar ways to the offshore oil and gas industries in an effort to cut costs. A growing number of innovative researchers in academia and industry are developing robots for use in offshore renewables. Their work draws on decades of experience gained in using robots in the offshore oil and gas sector.

A growing number of innovative researchers in academia and industry are developing robots for use in offshore renewables. Their work draws on decades of experience gained in using robots in the offshore oil and gas sector. The offshore oil and gas industry has effectively been using marine robots since it started in the 1960s,” says Dan Toal from the University of Limerick, Ireland. The original autonomous underwater vehicles (AUVs) were built around then.” The use of marine robots is driven by cost and their potential to be superior to their human counterparts and to operate in harsher environments. The sector has always been interested in how it could reduce the use of commercial divers because the health and safety aspects make using them hugely costly,” says Toal. The marine technology sector as a whole is also closely linked to the price of oil. This means that in recent years, as fossil fuel companies have been hit by a fall in the price of a barrel of oil, the push to reduce costs in the sector through the use of robots has grown. The spurt in technology should also, ultimately, benefit the offshore renewables sector, even if the industry poses some additional challenges, says Toal. For oil and gas, robots are generally working on the seabed and, depending on the depth, it could be dark and turbid and there might be tidal flow, but the disturbance to the robots is relatively limited.” Offshore renewables such as wind, plus wave and tidal if and when they become commercial, have to operate in very challenging shallow sea conditions, where storm force winds whip up huge seas. In such conditions most ships head to port, says Toal. Oceaneering, an American company with headquarters in Texas, designs, builds and operates the world’s biggest fleet of remotely operated vehicles (ROVs), which are already working in the offshore wind industry in Europe for cable laying. About 25% of our revenue this year will be from the renewables sector,” says Simon Miller, the company’s business development manager. For the moment, the use of robots is primarily in the construction of offshore wind farms with their use for the inspection of turbines still very limited,” he adds.

Underwater robots

An ROV is an underwater robot that is tethered to a ship by a series of cables through which the robot can be remotely operated by a person on board. ROVs may include cameras, sonar systems and articulated arms that enable them to perform basic tasks such as retrieving objects or cleaning a surface. AUVs also include camera and surveillance equipment but operate without human intervention. They are programmed to follow a predetermined path and return to a predetermined destination. We are also starting to see more AUVs in renewables, with smaller autonomous vehicles that operate in shallow waters and do cable route mapping, surveys, that type of examination,” says Miller. Hybrids, crosses between ROVs and AUVs, are also starting to appear. Oceaneering is developing a subsea welding solution in response to a competition for new technology hosted by the UKs Carbon Trust aimed at completely removing the need to use divers. That’s in progress right now and it uses technology that we are transferring from oil and gas.” Likewise the company is transferring technology from the fossil fuel sector to try to solve the challenge of how to inspect floating wind turbine structures without having to take them off anchor and back to shore. Miller also points to the development of resident ROVs which can stay on the seabed and be remotely controlled from the shore. Oceaneering has completed a 21 day demonstrator resident ROV project for Equinor, formerly known as Statoil. That’s 21 days without a vessel, 21 days of people in the comfort of an office rather than offshore and 21 days of no emissions.” The company’s aim is to have six months of operation subsea with no vessel and no people”.

European cooperation

In April 2018, Toal’s centre in Ireland launched a €2 million remotely operated underwater vehicle that will be used to inspect, repair and maintain marine renewable energy facilities. We are looking at putting dynamic positioning capability on the robots so they can reject wave motion, increasing currents and other challenges and hold position,” he says. At the moment they can hold a static position and not be pushed off.” The aim is to develop the technology so that if a robot is close to a floating, moving structure it can hold a relative position, in synchronism with the moving structure. Toal’s centre is one of 15 partners in ten European countries that launched a new EU Marine Research Infrastructure Network in March 2018. The network aims to open transnational access to significant national marine robotics research and development assets such as research labs with test tanks, vessels and robots across Europe. Another network partner is the Norwegian University of Science and Technology, which has a marine structures working group focusing on offshore renewables. I think in terms of the use of robotics the main tasks will be the inspection of power cables and the seabed prior to installation,” says Martin Ludvigsen of the university’s marine technology department. There will be some need for remotely operated vehicles and AUVs during installation and, when in production, to inspect the cables, pipelines and seabed installations.” These tasks are quite parallel” to those in the oil and gas industries and so the technology should bring down the cost of offshore wind or other offshore renewable energies, adds Ludvigsen. Obviously in oil and gas the most expensive element is ship time so everything we do with robotics or sensors that can reduce offshore vessels contributes to making offshore wind more feasible.” In terms of savings, an offshore vessel costs between €20,000 and €50,000 a day. If we can save one or two or 20 offshore days by using robots then of course the savings can be significant.”

Modular systems

Roberto Galeazzi of the Technical University of Denmark is another researcher working on marine robotics for offshore wind. His belief that there is room in offshore wind for cheaper, easier-to-use and more reliable robotic technology led him to launch the Reconfigurable Modular Robotic System for Aquatic Environment project in 2016. The idea is to develop a robotic system which can change morphologically and functionally according to the type of tasks that need to be done,” he says. We started with a standard off-the-shelf produce that we purchased from a third party American company with limited capabilities. By developing technology around the robot, we have increased the amount of tasks it can perform.” Since the beginning of the project, his team has developed laboratory infrastructure and an intelligent so-called mechatronic system, a physical interface that can be attached to the robot to enable it to be connected to a particular surface or to another robot. For now the system is confined to student projects as the initial €120,000 in funding has finished. Galeazzi rues the fact that there is generally less finance available to invest in robotics for renewables specifically than in the offshore oil and gas sector. Offshoreenergy.dk, a Danish offshore-energy industry organisation, has a number of current and planned projects in robotics, mainly in the use of aerial drones. The engine in our innovation projects is always reduction of cost through new innovation,” says Glenda Napier of Offshoreenergy.dk. Automation, drones, sensor technology and digitalisation are generally the keys to innovation.”

High quality results

Across the Atlantic in the US, the use of marine robotics in the renewables market is pretty minimal, says James Bellingham of the Center for Marine Robotics at the Woods Hole Oceanographic Institution, Massachusetts. Renewables are not as far along in the offshore environment as they are in Europe. We are just creating some of our first offshore wind farms.” Bellingham is, however, confident the renewables industry will follow the same trend as the oil and gas industries. As the cost of the platforms gets lower and lower it allows the operational folks in the industry to experiment and find uses for these robotics systems that perhaps the designers and even the companies that built them didn’t anticipate,” he says. And I expect that’s what will happen with offshore wind.” He predicts the future will see drones inspecting the upper parts of offshore wind turbines, lower cost ROVs inspecting some of the lower parts and then, ultimately, more expensive systems like AUVs surveying elements of the system … to get really high quality, high resolution” results. Oceaneering is already starting to make this vision reality with a part share in ASV, a company working on unmanned marine systems. It builds and converts existing vessels to become autonomous, remotely operated vessels, with a view to developing drone and ROV solutions that allow topside and sea inspection at the same time. For Miller the future is all about automation and robotics, as much for renewables as oil and gas. Our next generation systems which come out next year will be targeted towards wind farms.”

Writer: Iva Pocock