While companies such as Norway’s OHT have invested in specialised vessels for offshore wind transport and installation services, traditional oil and gas contractors have typically made use of existing assets to kick-start growth in the burgeoning sector.

OHT is building the world’s largest wind turbine foundation installation vessel, called Alfa Lift, with China Merchants Heavy Industry (CMHI).

This vessel, to be delivered next year, is designed to install monopiles and jackets from a floating vessel in dynamic-positioning mode and will start providing these services from 2022 on the Dogger Bank wind farm in the UK.

OHT recently entered into a binding Heads of Agreement with CMHI for the construction of two GustoMSC design self-elevating wind turbine installation vessels (WTIVs), with options for two more.

The vessels will feature battery hybrid solutions, electrical and control systems designed to reduce carbon dioxide emissions, and can be adapted for installation of fuel cells powered by hydrogen.

Busy colossus

The brand-new hardware contrasts with the stalwart Saipem 7000 giant heavy-lifting vessel, which is being used intensively on a growing list of wind projects including the Dogger Bank, Neart Na Gaoithe (NnG), and Seagreen wind farms in the UK, as well the jacket and topsides of the offshore substation at the St Brieuc wind farm and, in all probability, other new projects off France.

Saipem says it is using an existing fleet to handle most installation work as a way of building up business quickly, even though there is recognition that self-elevating WTIVs are the preferred method for installing wind turbine generators (WTGs) on bottom-fixed foundations, albeit with some exceptions due to soil conditions, such as in the Baltic Sea.

“As a company, we can do all aspects of installation for fixed-foundation wind farms, even though we don’t have our own jack up," says Guido D’Aloisio, Saipem’s head of offshore renewables.

"But this would only work for us on (engineering, procurement, construction and installation) with full balance of plant, rather than a multi-contract approach,” he says.

Saipem has already taken a lead in floating wind with pioneering operations on the Hywind Scotland wind farm, using the Saipem 7000 for mating WTGs and spars.

However, growth prospects for offshore wind mean the Italian contractor has also begun to invest in specialised equipment in areas such as as drilling for monopiles, and management is now analysing proposals for modifying existing vessels or building specialised new ones.


Subsea 7 has been taking advantage of spare capacity in its conventional subsea construction vessels through "double-hatting", or conversion.

The fleet at the service of the company’s Seaway 7 renewables and heavy lifting business unit includes the crane vessels Seaway Strashnov and Seaway Yudin, plus the cable-lay vessel (CLV) Seaway Aimery and the installation support vessel (ISV) Seaway Moxie.

The pipelay and crane vessel Seven Borealis is available for heavier lifting which, with a new generation of 15MW wind turbines around the corner, is likely to be required more often.

The UK-based contractor has promised to continue with disciplined investment in new vessels, driven by market growth and size of structures.

Current investment along these lines includes a $25 million project to convert the pipelay vessel Seven Phoenix into a CLV that has a 15-year design life.

Described as a relatively low cost and fast conversion, the CLV Phoenix is due to join the active fleet in the second quarter of 2021 and, with a strong pipeline of cable-lay projects, is already fully booked through 2022.

“Studies are under way to look at another four vessels which can be transformed quite quickly to hybrid vessels for the offshore wind sector,” Subsea 7 chief executive John Evans told investors in an online event recently.

Mexican musing

Growing opportunities in offshore wind transport and installation services are starting to attract a wider range of companies seeking refuge from a troubled oil and gas sector.

This can even be seen in Mexico, a country where demand for offshore services from state oil company Pemex has plummeted yet the oil-addicted administration of President Andres Manuel Lopez Obrador remains hostile to renewable energy.

Mexican contractor Marinsa, which is part of the CEMZA group, is looking to market the multi-purpose support and crane vessel Puerto Real which has sail-away scheduled for December, and is looking outwards.

“We are looking to market this new vessel for international clients and we see opportunities for it in the renewables sector,” Joel Ulloa , CEMZA’s global business operations director, tells Upstream.