Offshore wind’s role in a reliable renewable grid for Australia

Offshore wind power is emerging as a key renewable energy source in the global clean energy transition. This technology offers a proven form of large-scale power generation with the potential to replace traditional fossil fuel power generation in many coastal regions around the globe.

As Australia rapidly transforms its energy landscape, where does offshore wind fit in the overall energy mix, and how can we leverage the substantial investments into this emerging industry to maximise its social and economic contribution?

In this article, Dawn MacDonald, AECOM’s Global Offshore Wind Sector Lead, explores what offshore wind can offer Australia, the likely challenges ahead, and the support mechanisms needed to create a thriving domestic industry.

Q. What role can offshore wind play in Australia’s renewable energy transition?
A. Offshore wind can play an important role in an overall energy mix. Expanded global deployment and rapid technological development mean wind energy is increasingly one of the most cost-effective energy sources, with its levelised cost of energy (LCOE) factors on par or below fossil fuel sources in many cases. The LCOE measures the average cost of generating one kilowatt hour of electricity over the lifetime of an asset and is a key decision-making factor for investors. Offshore wind projects are frequently a better fit to replace existing fossil fuel power plants, relative to other forms of renewables, due to the much larger scale of the projects and the predictable power output enabled by access to stronger and more consistent wind resources.

The offshore location also offers significant benefits with very limited impacts on public lands. From a stakeholder perspective, you’re not in anyone’s backyard. Stakeholders are typically concerned with visual impacts and transmission line placement with onshore wind projects. When we take these elements offshore, we can reduce these impacts substantially, with turbines largely out of sight of coastal areas (frequently over the horizon) and much of the export cable located underwater.

Q.What role does government support play in realising offshore wind projects?
A. Government incentivisation and support are significant accelerators to offshore wind projects in new markets. Over the last decade, the offshore wind sector has dramatically reduced its average LCOE, mainly due to technological improvements and economies of scale, based on early projects that have enjoyed European nations’ subsidies. These subsidies worked to de-risk projects for developers, encouraging early investments and development of supporting infrastructure. Today, Europe’s offshore wind sector is largely independent, benefiting from these early government mechanisms and initial supporting infrastructure to kickstart the industry.

Australia is in a unique position geographically due to its distance from the supply chain, which is mainly located in Europe, and its market size. It is very likely to need initial support and de-risking so that investors in offshore wind projects, the ports, and the supply chain have confidence that they can invest for the long term.

Q. What are the key considerations when integrating offshore wind into existing electricity grid infrastructure?
A. Generally, offshore wind projects are large power plants with substantial new infrastructure required, including ports and transmission system upgrades, to inject electricity into the grid. There may be cost and environmental benefits to developing common transmission infrastructure for the sector, such as common corridors for multiple export lines or shared substation infrastructure . However, these benefits must be assessed against the risk of over-investment by grid operators if the projects aren’t realised. Ultimately, the power user will bear the grid infrastructure cost, so we must strike a balance. Long-range planning and investing early for future development, where possible, will help us transition more projects in the future.

Export cables are some of the most critical infrastructure in an offshore wind farm, as power delivery to the grid is impacted if these cables are damaged or installation is delayed. Determining the onshore components, including the landing point and the route to the point of interconnection, is one of the more critical design decisions in the eyes of many stakeholders and requires extensive stakeholder engagement and planning to minimise impacts and ensure safe and reliable installation and operations of the system.

Q. How can we properly consider environmental impacts when delivering new offshore wind farms?
A. Offshore wind projects are major infrastructure, and environmental considerations must be front of mind from the beginning of the development process. Wildlife, particularly birds and marine mammals, is a key concern and should be thoroughly investigated during the planning and permitting phase. This means developing a robust understanding of the baseline populations and behaviours of relevant species so that we can understand the potential future impacts of turbines and other infrastructure.

Impacts on bird species are frequently top of mind for stakeholders when considering wind energy projects. Environmental assessments evaluate the specific bird species in the development region and typically consider impacts on feeding, nesting, and migration. For offshore wind projects, project layouts, turbine design and even installation or operation techniques or schedules can potentially be adapted to minimise negative impacts. Developers can look at mitigation options for those that cannot be avoided, such as developing new nesting areas or mitigating residual impacts.

When locating an offshore wind farm, commercial and traditional fisheries and fish spawning areas should also be considered to understand how installation strategies or design decisions might impact various fish and shellfish. Working with local traditional, commercial and recreational fisheries stakeholders, potential impacts can be identified, relevant processes for interaction during construction and operation can be developed, and appropriate compensation structures can be implemented as required.

Marine animals can be affected by noise, primarily during the construction phase, depending on the type of foundations used. Fixed bottom foundations, installed using a driven pile, can create significant noise impacts as the noise from hammering travels substantially further underwater than in the air. We’ve seen several innovative solutions out of Europe for dissipating and dramatically reducing this noise, from physical barriers to ‘bubble curtains’. A thorough understanding of the baseline conditions paired with a detailed technical review of site conditions, considering relevant technological options, can provide a view into the potential impacts and mitigation options for installation at a particular site.

An exciting and emerging element in the sector is that we are now looking at how offshore wind farms can improve biodiversity. For example, many offshore wind farms don’t allow most forms of fishing or extensive marine traffic between the turbines and, by extension, effectively create a semi-protected area for marine life. The steel structures and rock armouring for scour protection can become habitats, stimulating feeding and providing sanctuaries for certain types of marine wildlife.

Want to learn more about offshore wind in Australia? Watch our webinar Making offshore wind a reality: a local and global perspective here