Hydrocarbons will remain part of the energy mix for the foreseeable future, but today’s reserves often lie in deeper and more inaccessible waters.

Meanwhile, rapidly developing offshore renewables – wind, sun, and waves – are already generating demand for increasingly sophisticated vessels, a trend that will only accelerate from here.

Global energy demand means oil and gas will continue to play a key role though they will be more ‘sustainable’ over time. However, renewables will contribute a steadily increasing share of the total, but harnessing renewable energy presents new challenges.

That means tomorrow’s offshore oil and gas must be developed, and that will be in more challenging locations – in deeper more exposed waters further from shore. Both fixed and floating energy plant will require a new generation of more sophisticated and powerful support ships.

Offshore support construction vessels (OSCV) are already required for new oil and gas installations, but their specs are becoming increasingly complex. They are designed to operate in some of the world’s most dangerous sea conditions in deep and ultra-deep waters. 

FPSOs are the only means of harnessing oil resources off the coasts of Brazil and Guyana, for example. They operate in the Santos and the Guyana-Suriname Basins respectively, up to 150km off the coast in water depths of 2,000m or more.

OSCVs are required to link long flexible risers connected to the seabed with FPSOs using spread mooring or turret systems, allowing them to swing with winds and currents. The OSCVs DP3 systems keep them in position in the most challenging seas. They facilitate not only installation, but also ongoing service provision, ROV inspections and constant maintenance.

An ExxonMobil-led consortium has deployed four large FPSOs so far in the deepwater Stabroek Block 190km off the Guyana coast. Two more units are to be installed in the coming months and another one is likely to come on stream in 2029, taking total production to about 1.5 million b/d.

The floating LNG (FLNG) sector is expanding, eight FLNG facilities are in operation already, with nine more under development. Today’s liquefaction capacity of close to 17 million tonnes/annum (mtpa) will be boosted by more than 20mtpa currently under development. Analysts at Oslo-based Rystad Energy forecast recently that capacity will reach 42mtpa by 2030 and 55mpta by 2040.

Floating assets are much faster to commission than fixed installations, with clear implications for project economics. Shell’s newbuild Prelude FLNG, deployed on the Browse Basin off Western Australia and admittedly the first such project, took more than seven years from final investment decision to first gas.

That was a full FLNG production plant with a design capacity of 3.6mtpa. Vessel conversions are much faster. Although they are not full production units, floating storage and regasification units (FSRUs) offer an example. Using a conversion strategy, Germany replaced gas imports piped from Russia with four, soon to be five, FSRUs. The first began operation just 10 months after the Russian invasion.

These highly complex assets may be purpose-built or adapted by adding liquefaction and other processing equipment to existing LNG hulls. And there is currently a ready supply of around 200 steam-turbine LNG carriers which cannot compete effectively in today’s market and are potential conversion candidates.

Each project has unique features and their complex development requires feasibility studies; asset choice – fixed or floating; formal business case; design; classification, assurance and commissioning; and through-life condition monitoring and surveys.

Uptime targets of more than 95% are commonly required and assets – whether conversions or newbuilds – may be expected to remain on station for up to 20 years and require in-water surveys throughout that time. They therefore must have through-life maintenance strategies drawn up on a project-specific basis.  

As the world faces increasing urgency to decarbonise, offshore wind capacity is expanding dramatically, with China firmly in the lead. The country accounts for more than half of installed capacity and nearly 80% of recently installed plant.

Vast jack-up platforms are required to ship components from shore, securing monopiles into the seabed and then adding a range of components up to the blades themselves. The largest of these, developed by Dongfang Electric Corporation, generates 26MW of electricity with the largest 153m-long blades so far sweeping an area of 77,000m², equivalent to more than 10 football pitches.

Wind farms elsewhere, though smaller, nevertheless require a range of vessels for installation, operation, and routine maintenance. And a drive to power these units with renewable electricity is rapidly gathering pace.