Breaking boundaries

environmentally sensitive. Consequently, renewable energy projects have been slowed due to complex regulatory and permitting regimes.

There is a great opportunity for naval architects and marine engineers to confront this challenge and apply their advanced knowledge and technologies developed originally for the offshore oil and gas sector, to the offshore renewable energy sector.

Offshore wind reached a significant level of development in Europe and is expanding in Asia and North America. Increased turbine sizes have played an important part in bringing the cost of offshore wind down to more competitive levels. Larger, taller, and heavier turbines require the development of supporting structures that are of cost-effective construction, transportation and installation, as well as optimised motions and operational performance.

The latest generation of turbines may require lifting and installing foundations weighing up to 2500 t, as well as turbine components of up to 1250 t to a height of 150 m. Jack-ups provide a flexible and stable platform not only for these major crane lifts, but also for the transportation of foundation and turbine components between fabrication sites, ports, and wind farm locations.

A full-scale offshore wind farm could require the installation of 100 or more turbines in a time scale of months, therefore necessitating far more frequent rig moves than those required for offshore oil and gas drilling. Turbine installations also present unique challenges that can have implications on hull form, leg structure, jacking systems, preloading operations, emplacement and removal operations, and severe weather procedures.

The location of floating wind farms further offshore is under consideration to capture a greater share of offshore wind resources in deeper waters, particularly off the US West Coast as well as Hawaii, Japan, and Korea.

Many naval and marine technologies used in the offshore oil and gas industry play a key part in developing offshore wind resources at sea. Piled fixed platforms and monopiles, gravity-based foundations, jack-ups, Tension Leg Platforms (TLPs), and moored floaters such as spars and semi-submersibles, are some examples. Spars and TLPs have good in-place motion capabilities

Figure 1. GustoMSC Tri-Floater, a floating offshore wind turbine.

Figure 2. GustoMSC SC-14000XL jack-up design with a telescopic crane for Shimizu Corporation. but tend to have higher and more complex installation operations with the associated cost and risk. Semi-submersibles, such as GustoMSC’s Tri-Floater (Figure 1), can provide greater flexibility in assembly, transportation, and installation, and can be designed for efficient motions and performances when afloat. In addition, offshore wind projects require many types of support vessels for cable laying; safety and security; inspection, maintenance and repair (IRM); and crew changes.

Hydrogen can also play an important part in accelerating the energy transition. Currently, hydrogen is mainly produced industrially from natural gas, which generates significant carbon emissions – grey hydrogen. The hydrogen is split from natural gas and the resulting carbon is released as CO 2 into the air. Many industrial processes use grey hydrogen while manufacturing their products.

Blue hydrogen can also be produced by stripping hydrogen from natural gas. However, the carbon components are then captured and injected into depleted gas fields or other utilisations of carbon such as in synthetic fuels. Carbon capture use and storage (CCUS) projects have been and continue to be developed in Europe. For instance, in the Northern Lights project in Norway, Equinor is drilling wells not with the aim of finding oil or gas, but to find suitable geological formations for the injection and storage of CO 2 . Another example is the Porthos project in the Netherlands whereby the CO 2 generated

from onshore industrial plants is collected, comingled, and transported by a subsea pipeline to a depleted offshore gas field for subsequent injection and safe storage.

Green hydrogen can be generated by renewable energy sources without producing carbon emissions, but it comes at a higher cost. The electrolysers used offshore to generate the hydrogen from seawater are powered with electricity supplied from offshore wind turbines. The process generates hydrogen and oxygen, the latter which can be released into the air without causing detrimental environmental effects. The electrolysers are installed on existing (and, in the future, on new) offshore oil and gas production platforms. Existing offshore gas export pipelines will transport the hydrogen to the onshore receiving stations. There, the hydrogen can be used threefold: as fuel for transportation, as feedstock for the petrochemical industry, or as fuel for power plants generating electricity.

The most important challenge for renewable projects is to achieve cost levels that are competitive with other utility scale energy sources. Naval architects and marine engineers can help with their experience from the oil and gas industry to make strides to significantly reduce breakeven costs for offshore projects. Areas of interest include: > Design, digital modelling, and analysis skills applicable to the marine environment: Naval architects digitalised ship design before digitalisation was a trend. High fidelity models are used in design, fabrication, and integrity management, with structural digital twins now enabling real-time stress analysis considering the results of on-board inspections. These emerging technologies give owners and operators a vastly enhanced level of visibility over the condition of their assets, reducing cost and improving safety.

Advanced engineering models: The oil and gas industry developed modelling techniques that are of direct relevance to renewable energy. For example, GustoMSC is utilising advanced earthquake analysis methods from the oil and gas industry, such as plastic collapse (pushover) analysis, to address the challenges of the growing offshore wind industry in Japan, as seen in Figure 2. Another increasingly accepted technology is computational fluid dynamics (CFD), replacing or enhancing costly model and prototype testing in the marine environment.

Validation of advanced models against field measurements: Extensive measurement campaigns in the 1980s and 1990s supported the development of more sophisticated jack-up structure-soil interaction models that are incorporated into international oil and gas standards today.

Figure 3. OCEAN 1100HE semi-submersible design series.

Figure 4. Askeladden, a GustoMSC CJ70 drilling jack-up design.

GustoMSC supported several of these initiatives and is executing a major campaign of jack-up performance measurement at the Askeladden jack-up rig in the harsh environments of the North Sea (Figure 4). GustoMSC is also working closely with wind farm installation contractors in acquiring performance data from jack-up units to improve operational efficiency and safety.

Development and application of marine industry standards, with an understanding of complex safety regimes and a focus on safety, reliability, and environmental protection: Oil and gas experts working on a voluntary basis in industry committees have driven many technology developments and

international standards. Joint industry projects (JIPs) have also been key instruments in advancing new ideas. The same template is helping the offshore wind industry.

An understanding of complex systems engineering applicable to the different types of marine systems and their interrelation: GustoMSC is studying the design of a semi-submersible rig taking advantage of concepts such as digitalisation, electrification, systems engineering, robotisation, and the reduction of carbon footprints. Many innovative solutions are integrated, such as remotely operated material handling, an unmanned drill floor, digital logistics, reduced manning levels offshore with shore-based monitoring and control, hybrid propulsion, and self-learning power management. The process involves developing key performance indicators (KPIs) for each solution as well as evaluating their technology readiness level (TRL). The most promising solutions are incorporated into GustoMSC’s semi-submersible design portfolio, as shown in Figure 3. Many such solutions will assist the offshore wind industry in improving capital and operational efficiency.

Contracting strategies to deliver capital projects in a profitable manner: Projected capital investment in US East Coast offshore wind may exceed US$100 billion in the next 10 years. The delivery of large offshore capital projects in the oil and gas industry involve marine design, shipyard construction, and offshore transportation and installation of major assets. Naval architects and marine engineers bring a wealth of experience and lessons learned from these projects.

Synergy of solutions for the marine environment: For example, inter-array and power-to-shore cables present challenges for offshore wind farms that can benefit from oil and gas industry solutions for subsea cables and pipelines. On the other hand, the oil and gas industry may be looking at powering its rigs from the shore, creating an interesting interplay between oil and gas and renewable technologies.

Redevelopment of depleted fields: The capture and storage of CO 2 offers a business opportunity to redevelop mature and decaying offshore oil and gas fields in areas such as the North Sea. Excess CO 2 can also be used for enhanced oil recovery (EOR). The injection of CO 2 into producing oil reservoirs is a known technology, especially in onshore oilfields. By having CO 2 available at offshore sites, the injection of CO 2 in a producing offshore oilfield will enable an increase in the recovery factor of oil from the reservoir, thereby enabling an economic advantage for the field operator and the countries where these operators are active.

Creative work in diverse, multi-cultural, multidiscipline environments: As the offshore wind industry grows from its established base in Europe to other continents, it will benefit from the lessons learned by the diverse oil and gas workforce. This workforce brings the experience of managing large interdisciplinary and complex offshore projects, and working in project teams dispersed across execution centres in different countries and time zones. Successful oil and gas offshore projects require co-operation with a range of technical, behavioural, and business disciplines, not only in the sense of technology and economy but also in the area of health, safety and environment (HSE). In addition, the offshore renewable energy business can benefit from the established international supply chain which has been developed by the oil and gas industry since the 1970s.

The 3Ps (people, planet and profit) are essential to guarantee a healthy future for the offshore renewable energy business, not just 2Ps (people and planet). Without developing profitable business, renewable energy business will fail to survive.

Raising the standards of living of a growing population remains the great challenge of our time. The human development index (HDI) is a composite index of life expectancy, education, and per capita income indicators. It is used to rank countries in terms of human development from zero (completely undeveloped) to one (fully developed). Presently, approximately 20% of the world’s population lives in countries with a HDI better than 0.8, and that percentage is expected to significantly increase by 2040 as many populous nations progress towards a higher HDI. Raising HDI for the poorest nations could mean increasing energy consumption per capita by a factor of five or more.

Powering the world towards high development levels in a sustainable way requires a great deal of co-operation, advanced technology, and purposeful innovation. Oil and gas companies and their value chain are transforming themselves into a broader energy ecosystem where oil and gas supply will continue to play an important role and where skills will be transferred to renewable forms of energy.

Naval architects and marine engineers are challenged to continue improving the efficiency and safety of the oil and gas industry by developing the rigs and platforms of the future. These initiatives will make their way into the renewables industry and will contribute to improve the profitability of renewable energy projects, while maintaining a sharp focus on personnel safety and environmental protection.

With the increasing pace of change towards renewable energy sources, offshore wind technology plays a key role globally in supporting this transition to cleaner energy sources. The richest wind energy resources are found offshore, with development of shallow water locations escalating with increasing volume and pace, and the industry moving forward with firm plans to tap into the even greater opportunities in deeper waters through the application and development of floating platform technologies. By 2025, it is anticipated that close to 20 000 turbines with more than 250 offshore substations will have been installed offshore. Even with the development of larger turbines, these quantities are expected to increase by a factor of three or more by 2050, according to IRENA and Rystad Energy.

Critical to the successful operation of turbines are the subsea power cables that have the essential function of transmitting generated power from the turbines to the substations (electric hub of the wind farm), and then onward