By Patricia Seoane da Silva, Lux Research

Rapid technological developments in recent years have brought about a sea change in green energy thinking and generated a rising tide of global interest in offshore wind farms.

Last year alone, China installed around 17 gigawatts (GW) of offshore wind capacity – more than the combined total built by every other country in the world over the past five years. China now has around 26GW of offshore wind capacity – almost half the worldwide total of 54GW.

Hong Kong is meanwhile looking to get in on the act as it works towards a target of achieving carbon neutrality by 2050, in part through the development of zero-carbon and renewable energy, including wind energy. 

The city’s biggest energy provider, CLP, is carrying out a feasibility study into an offshore wind farm in the south-eastern waters of Hong Kong. Early findings indicate improvements in turbine technology and costs make offshore wind farms an increasingly viable medium-term option.

In Europe, Japan, South Korea, and Taiwan, there has been a strong push to increase offshore wind capacity – but the technological potential continues to be limited by the elevated capital costs involved.

The key to achieving the cost reductions necessary involve economies of scale, collaborative innovation, and institutional support. 

Foundations for growth

Foundations represent around 29% of the capital costs of offshore wind farms, according to a report from the U.S. Department of Energy’s National Renewable Energy Laboratory. This means that their mass production would significantly reduce costs.

Assuming cost decreases by 15% for every doubling of production volume, the capital costs for floating wind could decline by nearly 40% if the number of installations increased by an order of magnitude. 

While the three foundation topologies currently dominate the floating wind landscape, other novel designs with potentially lower cost per watt ratios – such as mini-turbine platforms – are being experimented with.

While conceptually advantageous, these designs are unlikely to succeed due to their mechanical complexity, and the industry is expected to lean towards semi-submersible foundations and, to a lesser extent, spar-buoy foundations.

Innovative partnerships

Offshore wind technology is far from mature, and environments further offshore need to be better understood for the technology to turn today’s interest into practical commercial deployment.

The industry must gain better understanding of wind and wave interactions, as the natural frequency of offshore wind turbines is significantly higher than that of bottom-fixed turbines – more than 100 seconds, as opposed to less than three seconds.

This difference makes offshore wind turbines more prone to heavy oscillations, which calls for renewed design rules to mitigate the increased effect of structural fatigue.

In addition, available wind resources at waters deeper than 60 metres need to be accurately assessed to optimise power production and develop offshore wind farm design procedures.

Collaboration is critical, and the industry is beginning to see industry leaders like Equinor partnering with Masdar and ORE Catapult to share offshore wind data.

Similar formal and informal partnerships need to be replicated. Collaboration between developers, energy companies, and governments are essential for the industry to grow.

Institutional support

In the final analysis, offshore wind remains a relatively expensive form of power generation, and financial support is needed to secure its long-term adoption.

Combined with the decarbonisation efforts of countries which may otherwise lack the land resources for conventional wind farms, top-down government initiatives remain a pivotal third factor for offshore wind development. 

China, for instance, has set targets for its combined wind and solar power capacity to increase to 1,200GW by 2030 and for renewable energy to account for over half of total installed power generation capacity by 2025.

Research and development support must also continue, as well as participation from key infrastructure players to enable offshore wind turbine assembly and installation. A successful example of this is the port of Rotterdam, where an expansion of offshore wind power generation facilities is being progressively implemented.

Institutional support is the key to unlocking existing infrastructure and bringing together key stakeholders to establish an effective long-term offshore wind supply chain.