The global offshore wind fleet will swell from the current 25GW installed to almost 165GW by end of the decade before expanding at a pace with the addition of a fast-industrialising floating sector to reach around 420GW by 2040 – pulling in $1.3trn in total investment and creating 8 million jobs in the process, according to latest calculations by UK analysts Rethink Energy.

Installation rates will hit an average of 30GW a year, the group predicts in a new report, as Europe loses its sector primacy in 2026 to an Asia Pacific market supercharged by an explosive build-out off China, while the US falls behind due to headwinds created by “conflicting politics, as well as its lack of maritime and transmission readiness.”

“The emergence of transboundary grids in territory groupings, such as the EU, will be a key enabler and will have to happen first, before everywhere gets the full benefit of offshore wind,” said the report’s lead author Harry Morgan.

“But the major global effort in electricity generation from wind will shift from onshore, where it has been for some years, to offshore. The great bulk of LCOE [levellised cost of energy] reduction will be in offshore, making it a key technology of the next 20 years. We are not saying onshore is dead, but it will have lost its pre-eminence.

“While the global supply chain for offshore wind will benefit from the experience and scale of the onshore wind industry, [in] the US [this effect] will be limited in expansion due to a limited maritime resources, especially seaworthy installation and maintenance craft.”

“Later in the 2020s there will be a second coming, as more and more floating wind turbines are added to the mix, driving a growth in offshore wind greater than many analysts expect,” he added, noting that Rethink Energy expects floating wind’s LCOE to reach “a competitive level” with conventional bottom-fixed offshore wind “between 2028 and 2030”.

This cost reduction will be “partially achieved through the continued consolidation of global turbine makers, and of floating platforms once floating wind enters the fray at scale”, said Morgan, cautioning that “environmental issues will [continue to] plague the steadfast emergence of this massive industry, and act like a lead weight around its immediate progress until more countries provide evidence of the benign effects of offshore wind”.

Rethink’s figures outreach those of the International Energy Agency, which in its first standalone report on the sector forecast offshore wind would mushroom to become a main engine of the transition toward a decarbonised global energy system in the coming decades, with the worldwide fleet expanding 15-fold to reach at least 340GW by 2040.

Despite this, Morgan warns against over-optimism in the near-term, as he believes many governments have “over-promised” on offshore wind, citing Europe being expected to “miss its 2030 and 2040 targets but still reach creditable milestones of 82.7GW by 2030, and 170.4GW by 2040”, led by the UK, Germany, the Netherlands, France and Denmark.

The International Renewable Energy Agency has predicted the global offshore wind build-out could reach 1TW of plant by 2050. And the World Bank produced a study late last year that suggested “emerging” plays alone could ultimately add as much 3TW to the worldwide fleet.

A recent report from European wind advocacy body WindEurope pointed to Europe alone seeing its offshore wind plant base growing to 450GW by mid-century and meeting 30% of the continent’s power demand — but needing a “visionary” root-and-branch rethink of marine spatial planning to achieve this.