On 12 July 2023, the federal government announced the Hunter Coast as Australia’s second offshore wind zone. The announcement of a second offshore wind zone (alongside the Bass Straight off Gippsland) demonstrates that offshore wind – formerly believed to be ‘technologically impossible’1– is now a viable renewable energy source. As community acceptance of offshore wind (as an alternative to onshore wind) has grown, a secondary debate has arisen: to fix or not to fix?
It is a pressing question. According to the Global Wind Energy Council, approximately 80% of the world’s offshore wind is found in waters deeper than 60m.2 However, the technical capacity and bankability of floating wind farms lag significantly behind its fixed-bottom counterparts. For example, the world’s first fixed-bottom wind farm (Ørsted’s ‘Vindeby Offshore Wind Farm’) was commissioned in 1991. By contrast, the first floating wind farm (Equinor’s ‘Hywind Scotland’) was only commissioned in 2017.
This article compares the key differences between fixed-bottom and floating wind farms, and discusses the impact of each on the marine ecosystems and coastal communities.
When to fix and when to float?
The below table sets out the key characteristics and differences between fixed bottom and floating wind farms.
|Description||Monopiles are drilled into the seafloor and operate from a ‘fixed’ location.||Monopiles are constructed on floating structures which are anchored to the seafloor by anchors, chains and sea cables. Designs vary – see Diagram 1 for examples.|
|Location||Depths up to 60m. Accordingly, fixed-bottom wind farms are located much closer to the coast.||In theory, capable of installation up to 1km above the seabed, and therefore has greater flexibility to be installed further out to sea in areas of stronger consistent wind.|
|Construction||Requires specialised installation vessels to install fixed foundations (for example, jack-up and dynamic positioning vessels).||Can be constructed onshore then transported to the offshore location using tugboats and cable-laying vessels, reducing installation costs.|
|Cost||Less expensive to construct.||Presently, more expensive to construct (however forecasts estimate this gap will significantly decrease over the next decade).|
Diagram 1: Floating offshore wind designs
Source: As compiled in BVG Associates, ‘Guide to a Floating Offshore Wind Farm’ (May 2023): https://guidetofloatingoffshorewind.com/wp-content/uploads/2023/06/BVGA-16444-Floating-Guide-r1.pdf
Impact on coastal communities
Coastal communities frequently resist the construction of offshore wind farms on the basis that the construction and operation would disrupt the livelihoods of fishermen and those operating in the tourism sector. For example, Blue Float Energy’s recent proposal to construct an offshore wind farm off the coast of Port MacDonnell, South Australia, was met with resistance by some within the 800-strong local community. The pushback was centered around concerns that the offshore wind farm would disrupt the natural ecosystem during the process of installation and operation, and affect visual amenity.
Public dissatisfaction with any new developments may be a deciding factor in the progress or termination of any renewable energy project, and offshore wind projects are no exception. Consider the Cape Wind project, a proposed wind farm off the coast of Massachusetts in the U.S. While the project received the necessary federal government approvals to progress with development in 2010, the Cape Wind project faced strong opposition from a variety of stakeholders, including environmental groups, nearby local townspeople and indigenous communities. Among others, concerns have included the size and unsightly appearance of the project (alleged to affect tourism and property values), wildlife and historic conservation issues, and a lack of transparency surrounding the cost of the project in terms of development and whether consumers would be entitled to a subsidy scheme for any energy generated by the project.3 Eventually, the protest lead to the termination of the entire project in 2017.
While these concerns are applicable to floating wind farms, it is notable that, when constructed onshore and installed further to sea, the impacts on fishing communities and visual and aural amenities are significantly reduced.
Relevance of offshore wind farms for developing nations
In 2019 the World Bank Group announced a limited but notable program, the WBG Offshore Wind Development Program, to fast-track the adoption of offshore wind in developing nations with significant offshore wind resources (including Brazil, India and the Philippines).4 Notwithstanding the present high upfront costs, floating wind farms have been touted as a partial solution to the energy crises faced by many of these countries. Floating wind farms will be particularly relevant to countries like the Philippines and South Africa, which have deeper seafloors.5
The Cape Wind project – and the current conflict with Port MacDonnell – provides us with the following key takeaways on how to move forward with offshore wind projects while maximising stakeholder satisfaction and minimising controversy:
- emphasise the need for open communication, transparency and public consultation, particularly for affected industries such as fishing and hospitality industries, prior to the planning and development of any floating wind farm projects;
- thoroughly evaluate the suitability of the proposed wind farm site, taking into account potential impacts on the environment from both a practical and visual perspective. This can be done through scientific research and consulting with local communities and other stakeholders; and
- at a governmental level, there must be further consideration on how to regulate the operation and development of floating wind farms and how these new regulations interact with existing legislation, ultimately to ensure that each relevant party’s interests are adequately protected.
1The Atlantic, ‘Floating Wind Farms are about to Transform the Oceans’ (4 November 2021): https://www.theatlantic.com/science/archive/2021/11/floating-wind-farms-california-marine-life/620489/
2IEEE Spectrum, ‘Floating Wind Farms Aim for Open Ocean’ (22 May 2023): https://spectrum.ieee.org/offshore-wind-floating-turbines
3Christina Riska Simmons and Elizabeth Wolzak, ‘Case Study: Cape Wind Project’ (20 May 2022): https://education.nationalgeographic.org/resource/case-study-cape-wind-project/
4The World Bank, ‘New Program to Accelerate Expansion of Offshore Wind Power in Developing Countries’ (6 March 2019): https://www.worldbank.org/en/news/press-release/2019/03/06/new-program-to-accelerate-expansion-of-offshore-wind-power-in-developing-countries
5The World Bank ‘Expanding Offshore Wind to Emerging Markets’ (31 October 2019): https://www.worldbank.org/en/topic/energy/publication/expanding-offshore-wind-in-emerging-markets