Where next for offshore wind?

Online Editor

In an exclusive interview, respected scientist John Olav Tande explores what’s in the pipeline for the offshore wind sector

On June 8th, 2020, the Ocean Renewable Energy Action Coalition (OREAC), a group led by offshore wind energy majors Ørsted and Equinor, announced its plans to install 1,400GW of offshore wind globally by 2050 to drive decarbonisation and a green economic recovery from the Covid-19 crisis. Norwegian offshore wind expert, John Olav Giæver Tande, describes 
the plan as, “ambitious but absolutely doable”.

Currently chief scientist at independent research organisation SINTEF, Tande has been engaged in wind energy research since graduating from NTNU (Norwegian University of Science and Technology) in 1988, including seven years in Denmark at Risø National Laboratory (now part of DTU wind energy) before joining SINTEF in 1997. He heads up the offshore wind energy activity at SINTEF and within the European Energy Research Alliance (EERA) joint programme on wind energy.

Throughout his long and productive scientific career, Tande has made a significant contribution to the acceleration of the clean energy revolution in the field of offshore wind power, and floating wind farms in particular. Tande was the initiator and Centre Director for the research centre NOWITECH (2009-2017), which generated 40 innovations with a potential net present value of about €5 million. 

Achieving their offshore wind energy potential

Although he believes OREAC’s plan to be feasible, Tande does acknowledge that there are a number of challenges in achieving it. “To reach the target the installed offshore wind capacity would need to increase with about 50GW every year. This is significantly higher than the current rate of offshore wind installation, but still realistic,” he comments. 

“It would require an acceleration in the development with more industry and jobs directed towards offshore wind energy. The development of onshore wind has proven this to be possible, with annual installations around 50GW for the past few years.”

Tande observes that the ambition also aligns nicely with the scenario set forth by the European Commission of between 230 and 450GW of offshore wind by 2050 as an important part of reaching climate goals.

Technical hurdles to the offshore wind energy goal

As well as an industry push with resources and jobs directed to the sector, there are several technical challenges ahead. The key one is how to bring the power to shore and to design and operate the offshore wind farms so that they will ensure stable and efficient operation of the future power system with net zero emissions of CO2. Tande describes this as, “the science and engineering challenge of this century.” 

How, then, can this challenge be overcome? Tande observes that there are actually two challenges here. “One is to bring the power to shore, and the other is to integrate the power into the energy system. 1,400GW may give an electricity production of about 5,600TWh annually and would make offshore wind energy a cornerstone of the energy system. Thus, offshore wind farms must be connected and controlled in a way that supports the proper stable and reliable operation of the power system. 

“There are challenges in developing the subsea transmission system to transport the electricity which will be at a total different magnitude than we have offshore today, and we need to develop solutions to efficiently handle the natural variations in the wind generation. Forecasting of production, advanced control and systems science are key elements, but also alternative solutions should be explored. For example, using offshore wind to produce hydrogen, or to create charging hubs for electric-powered vessels, or other multi-use options.”

World’s largest floating wind farm

One novel approach that seems to have vast potential if it can be properly commercialised is floating wind technology. Tande says that, “there are increasing numbers of companies and countries that are pioneering within floating wind technology. The installations have so far been in Norway, Portugal, Japan, and UK, while France will have four floating projects in operation in 2021. 

“Equinor installed the first in the world full-scale floating wind turbine in Norway already in 2009 and in 2017, it installed the world’s largest (until now) floating wind farm in Scotland. Equinor has named its floating concept Hywind.Using a standard wind turbine on top of a spar-buoy type floater anchored with three mooring lines, Principle Power demonstrated its floating semi-sub technology named WindFloat first in Portugal in 2011 and the technology is now  about to put in operation (2020) for what will now be the world’s largest floating wind farm, Kincardine in Scotland, rated 50MW. In Japan a consortium of 11 companies established Fukushima FORWARD, which has developed (2013-2015) a floating wind farm with a floating substation and three turbines employing different floating technologies: compact semi-sub, advanced spar and v-shape semi-sub.”

Despite these flagship projects, Tande states that the technology and market for floating wind is still at an early phase globally, with only some tens of MW installed capacity, while the accumulated bottom-fixed offshore wind capacity is totalling about 30GW. He adds: “However, according to a detailed resource study by IEA, 80% of the offshore wind potential is at deep water that can only be rationally exploited by the use of floating technology. Therefore, floating will be vital for the further development of the offshore wind sector. Indeed, bottom-fixed will likely dominate for the next few years, but through development of the floating wind technology and supply chain, floating wind will become increasingly attractive. 

“Exactly how fast this development will happen, is not only a question of industry initiative or research, but also that policies are put in place with clear targets and economic incentives to accelerate the progress. For 2030, it is realistic to see a number of GW scale floating wind farms, and for 2050, I expect about one third of the global offshore wind capacity to be floating, possibly more.”

What’s ahead for the wind sector?

Looking ahead, Tande says that with regard to the two key trends discussed above – floating offshore wind technology and the integration of offshore wind energy to create zero-emissions power systems – adopting modern engineering solutions will assist in both aims. “Within both areas I believe digitalisation can play a major role in accelerating the development and creating value. We should aim for smarter design and operation, and ensure that at all times we have respect for nature and our joint well-being,” he concludes.

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