Finding the flow

The race for renewable energy

Many governments have set bold targets in a bid to reduce their carbon emissions. According to McKinsey’s Global Energy Perspective report, 64 countries have pledged their commitment to achieving net zero in the coming years.² One way to achieve this target is by diversifying away from the reliance on traditional fossil fuels and embracing the energy transition, with a move towards renewable energy sources. Indeed, countries and companies alike are investing heavily in this area. The International Energy Agency estimates that renewable energy capacity will have to triple if more than 60% of total electricity generation is to come from renewables by 2030.³

The wind energy market is growing and showing no signs of slowing down as governments worldwide seek to increase their capacity for renewable energy. The Global Wind Energy Council’s 2023 Global Wind report indicates that, globally, 77.6 GW of new wind power capacity was connected to power grids in 2022 (a y/y growth of 9%). Of this, 8.8 GW was from offshore wind, bringing the total global offshore wind capacity to 64.3 GW.¹

Offshore wind farms have a much larger generation potential than onshore wind turbines. There is a more consistent supply of higher wind speeds across the water compared to across land, and so offshore turbines can better harness the wind levels to produce more energy than onshore turbines. Also, their size is not restricted in the same way as land-based turbines are as there is less opposition to development from local residents.

However, there are several challenges to overcome in the development of offshore wind farms. These include limited accessibility, prevailing weather conditions, water depths, and the difficulty of bringing the electricity onshore to connect to the grid. In addition, there is a limited availability of specialist WTIV vessels and skilled operators. These factors are exacerbated by the trend towards even bigger and more efficient wind turbines.

Super-sized turbines

The world’s first offshore wind farm was built in 1991, in shallow waters off the coast of Denmark. The Vindeby site consisted of 11 wind turbines with blade lengths of 17 m and heights of 54 m, capable of generating 450 kW each.⁴ The annual power was equivalent to 2000 – 3000 Danish households.

Technology has come a long way since then. In 2023, the world’s first 16 MW offshore wind turbine was installed in southeast China’s Fujian Province. The wind turbine, which is positioned approximately 35 km from the shore, boasts the world’s largest per-unit capacity. The turbine is 152 m high and includes the world’s longest turbine blades at 123 m, with each blade weighing 54 t. The total swept area of the three blades is approximately 50 000 m², which is equivalent to the area of seven standard-sized football fields. At full wind speed, the wind turbine can generate 34.2 kWh of power after one full rotation. Its annual power output is estimated to average over 66 million kWh and is expected to meet the annual demand of 36 000 three-person families – replacing 22 000 t of standard coal and saving 54 000 t of carbon dioxide.

It is clear to see that wind turbine technology has made significant advances in recent years. As operators have sought to improve efficiencies and capacities, more reliable and larger turbines – coupled with larger rotor diameters and higher hub heights – have been designed and built. It is predicted that, by 2030, the industry will be deploying 20 MW turbines with rotors of up to 300 m in diameter.

The challenge with installation

WTIVs are vessels that have been specially designed to transport, install, and carry out maintenance and repairs on offshore wind turbines. In 2020, there were 16 WTIVs worldwide. However, current WTIVs will not be able to accommodate the next generation of larger-sized wind turbines, and so they need to be upgraded or new ones built. The next-generation turbines will need a crane capacity of 2500 – 3500 t to get them upright (compare this to 500 t in 2005 when the first jack-up was deployed for offshore wind). WTIV operators are already building cranes that will be ready to handle 20 MW turbines but, according to a report by Wind Europe, the demand for offshore wind turbines will outpace the supply of WTIVs capable of handling these new, larger turbines and there will be a shortage in 2024.⁵

The State of the European Wind Energy Supply Chain research, published by Rystad Energy, states that global demand for WTIVs is expected to grow more than five-fold towards 2030.⁶ Excluding Chinese WTIVs, the global number of operating vessels is expected to increase to 25 by 2026 (based on confirmed newbuild orders), and by 2030, 60 – 65 vessels will be needed.

Ensuring these vessels are built to install the super-sized turbines efficiently is important. Since offshore wind farms are situated in difficult to access locations, the failure of any equipment can be extremely expensive and can cause major project delays. Operators often rely on specific time slots that are dictated by the limited availability of vessels and crews, as well as by weather patterns, and it could take days for replacement parts to be delivered should one fail.

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Energy Global's Summer 2024 issue

The Summer 2024 issue of Energy Global starts with a guest comment from Terrawatt on the streamlining of the permitting process in Italy, before moving on to a regional report from Frost & Sullivan on the energy landscape in Asia Pacific. This issue looks at key topics such as wind installation vessels, offshore wind turbine foundations, weather analysis, solar maintenance, and more!

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