Wind energy – going offshore
Power and renewables Maritime

In 2017, wind power provided 4.1% of the world’s electricity output. However, in some regions, such as Europe and North America, its share reached levels as high as 9.5% and 5.6%, respectively1. In 2019, 47% of Denmark’s electricity was generated from wind power2, and the country is planning further expansion in the next few years. This uptake has been driven by financially supportive policies and a growing awareness of the impact of conventional energy sources on the environment and climate. In the future, we foresee support for onshore wind slowing in some developed countries, where the industry has reached a high maturity level, and where conflicts on wind turbine location are on the increase. For offshore wind, we expect strengthened support in countries with limited land areas, bypassing community opposition1, and a fast uptake of offshore wind in new regions where this technology is yet unexploited.

For offshore wind to be successful, the development of large wind turbines with a rating of 10+ MW is seen as key for cost reduction of offshore wind applications. Today, 9.5 MW turbines are in operation and a 12 MW turbine has been tested and begins commercial operation this year. In 2030, we may see turbines as large as 20 MW.

Wind turbine technology will further develop using new materials and advanced monitoring and control, making it fully competitive with conventional electricity generation. Cost reductions in floating offshore will enable new geographic areas to be developed where previously limited land availability or lack of shallow water hindered wind energy development.

Wind energy – going offshore - DNV GL
Wind grows to 30% of electricity generation by 2050
Opportunities and market impacts

Increased turbine sizes with larger rotor diameters that capture more power generated from the wind, are an important cost reduction driver. Other, less well understood, cost reduction drivers come from economies of scale in the increased size of offshore wind farms – which now often come in single or clustered sizes of more than 1 GW (1000 MW). There are of course cost reductions from needing to install fewer turbines – today, it takes less than 100 turbines to generate 1 GW from a wind farm at sea. With a 12 MW turbine it will take only 83 turbines and with a 15 MW turbine only 66, and so on. The use of multi-turbine structures in future may further reduce the balance of plant cost. The cost reductions will also be sizable in the annual operation and maintenance campaigns – ensuring continued cost reductions coming from offshore wind.

Looking at the next technology revolution in wind power, we need only to move from bottom fixed to floating solutions. The advantage of floating wind is that there are (almost) no size limits. Floating structures will facilitate installation of 10+ MW turbines now under development or multi-turbine designs. With offshore wind projects becoming standardized it will be possible to industrialize manufacturing in the second half of the 20’s. This will further reduce the levelized cost of energy (LCOE) as project costs are lower with larger turbines.

Floating wind provides greater flexibility during installation. For example, a structure can be assembled in sheltered areas, such as a quayside, and then towed to its final position. This also supports local manufacturing by using existing shipyard infrastructure, which will further reduce cost. Independence from water depth and soil conditions (to some extent) will allow the industry to standardize production of floating structures and manufacture in larger volumes.

With more fluctuating elements connected to the power grid, achieving and maintaining reliable operations under increasingly complex energy systems will be a growing concern. Thus, grid planning and standardization of substations, as well as grid connections combined with demand-side management and other sector couplings, will enable successful expansion of wind energy. The increased use of systems controlled by machine learning algorithms as well as increased use of robots and automation will enable further optimized operations and reduction of cost.

Risks and uncertainties

It is estimated that the LCOE will come down to $50/MWh for fixed offshore and $70/MWh for floating offshore wind in 20303. However, some believe that floating wind could be as low as €40/MWh4. The total offshore wind (fixed and floating) installed capacity will be in the region of 150 GW globally in 20301. For onshore wind the estimate from our Energy Transition Outlook is 1.5 TW of installed capacity.

To get an accurate handle on the LCOE, wind resource assessment methodologies may need to be adapted in order to correctly account for increasing wind farm cluster densities and their associated losses. While blockage losses are now being introduced by the wind industry, much needs to be understood about the magnitude of cluster to cluster wakes and their potential impact on the LCOE.

On the cost side, the total cost of a floating offshore wind project depends on many factors. One of the most important is the support structure it uses. However, the support structure is also important for its ability to help lower costs in other parts of the system, such as by enabling serial fabrication, inshore assembly, and commissioning, and by minimizing expensive offshore labour, including operation and maintenance 3.

However, the view that floating offshore wind carries a higher risk, which would lead to higher cost is unfounded. Today, it is not the technology risk holding back cost improvements in the wind industry – the leading players undertake independent certification and adhere to set standards. They also carry out thorough mechanical testing of prototypes, prototype testing in real-life environments and improvements of virtual and digital design and testing.

The business risks come from regulators who either do not understand what it takes to scale new industries by securing stable investment frameworks, or who set requirements for local production manufacturing that are too rigid and therefore restrict competition and economies of scale, leaving the full potential of offshore wind technology untapped. Therefore, to realize the full potential of global offshore wind energy, policy still matters to ensure economies of scale are achieved, lowering costs to levels competitive with onshore wind and other forms of electricity production.

Read more: Multipurpose offshore platforms.

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