Ride the wave

Sam Leighton, Managing Director, Bombora Wave Energy, UK,

details how harnessing wave energy could aid the world’s transition to a net zero future, highlighting technologies such as wave energy converters and hybrid wind and wave systems.

ounded in Perth, Western Australia, in 2012, Bombora Wave Energy has developed a solution to harness the power of ocean waves. Now on the cusp of delivering a powerful wave energy converter (WEC) – through its flagship 1.5 MW Pembrokeshire demonstration project, Wales – the firm’s utility scale solution is helping to accelerate the energy transition on route to a net zero future.

The word ‘bombora’ comes from the Australian Aboriginal language, meaning an area of large sea waves breaking over a shallow reef some distance from the shore. Now operating from headquarters in Pembrokeshire, it remains a symbolic masthead illustrating the company’s proud heritage and connection to the Noongar people as traditional custodians of the land on which it was founded.

Following a decade of intense research and development, Bombora is now ready to harness one of the world’s largest untapped energy sources – ocean waves – which contain approximately 2 TW of energy, enough to satisfy today’s entire global electricity demand.

Through its novel ‘mWave’ technology, Bombora will combat two key challenges which have hampered wave energy development in the past – the cost of energy production and the ability to withstand mighty ocean forces. Crucially, it has also been designed to capture wave energy at utility scale, producing consistent and cost-competitive renewable energy for commercial power generation.

Maximising energy capture

The mWave structure comprises of a series of air-inflated concave cell modules, fitted with flexible rubber membranes, mounted onto structures below the ocean surface. The cell modules are arranged at an angle to the incoming waves to maximise energy capture.

As waves pass overhead, air is squeezed out of each cell module in sequence, passing through one-way valves and into a duct system fitted with an axial turbine before being recirculated to refill each of the cell modules once the wave has passed. The flexible membrane is made from industrial grade rubber, which is renowned for its reliability and longevity following long-standing use across a range of other marine applications.

Containing no external parts, aside from the flexible and robust rubber membrane, mWave extracts power simply without the need for complex mechanical systems.

The replaceable modular design also helps streamline maintenance processes, minimising downtime and maximising power output. In addition, mWave’s cell modules have a unique ability to shut down in extreme storm events, helping limit design loads and reduce capital costs while improving the all-important cost of electricity.

In terms of site location, the cell modules can be configured to suit either fixed-bed nearshore foundation systems or floating offshore ocean environments.

Delivering powerful wave energy converters

In July 2022, Bombora entered the final test and assembly phase of its Pembrokeshire Demonstration Project, as it prepared to validate its WEC.

The £20 million initiative has been financially supported by the European Regional Development Fund (ERDF) via the Welsh government. It will catapult the region to the forefront of the global wave energy race, with plans to establish a sustainable industry, engaging local supply chain partners, and creating highly skilled employment opportunities.

Rigorous testing is currently being carried out on key sub-systems as the project progresses at pace, with the specialist mWave cell membranes undergoing extreme inflation and deflation cycles. This is the culmination of a full-system testing process involving detailed instrumentation, operation of the valve systems, and powering of the power take-off (PTO) module. Throughout the process, Bombora has applied acute attention to detail, pushing its technology way beyond the expected operational limits to ensure high performance levels, robustness, and durability.

In the coming months, the final assembly phase will begin quayside in Pembroke Dock before loadout to the operational site at East Pickard Bay, Wales, where the mWave technology will be validated in the open ocean, advancing it to technology readiness level (TRL) 7/8. The final 1.5 MW mWave device will weigh in at 900 t, with structural dimensions of 75 m long, 15 m wide, and 6 m high.

Hybrid wind and wave systems, and future multi-megawatt wave energy projects

Once operational, the Pembrokeshire demonstration project will provide Bombora with a blueprint for its future multi-megawatt wave energy projects, proving both

Figure 1. Bombora has developed a patented membrane-style wave energy converter, mWaveTM. mWave is unique among wave energy converters as it simultaneously addresses the cost of energy and ocean wave survivability challenges. This new approach proffers a new era for wave energy. In deep waters, mWave integrated with a wind turbine on a floating platform greatly increases seabed lease area capacity and output.

the reliability and competitiveness of its novel mWave technology. The project test plan involves operating mWave for a period of 6 – 12 months, after which it will be removed. While in situ, it will deliver key optimisation data to inform Bombora’s other initiatives, including the InSPIRE project, which is under development with global EPC contractor, TechnipFMC.

The InSPIRE project aims to unlock the enormous potential of hybrid wind and wave arrays, which are set to play a significant role in the future energy transition by combining complementary power profiles to deliver a more consistent and stable clean energy supply to the grid. Adding to the InSPIRE project, Bombora has worked with the offshore renewable energy (ORE) Catapult’s Marine Energy Centre of Excellence (MEECE) on the techno-economic appraisal of the mWave technology within co-located and integrated offshore renewable environments, providing more evidence to support future development.

A separate strategic partnership with Japan’s Mitsui O.S.K. Lines (MOL) is focusing on identifying and delivering wave energy projects across Asia, with funding already secured to conduct a feasibility study in Mauritius for the deployment of a utility scale wave farm leading to a 30+ MW project.

Transitioning to a net zero future

Transitioning to a net zero world is one of the greatest challenges humankind has faced, requiring a complete transformation of how people produce, consume, and move around. The energy sector ultimately holds the key to averting the worst effects of climate change, currently responsible for producing approximately three-quarters of greenhouse gas (GHG) emissions.

A growing coalition of countries, cities, businesses, and other institutions are pledging to reach net zero emissions. More than 70 countries, including the biggest polluters – China, the US, and the EU – have set a net zero target, covering approximately 76% of global emissions. More than 1000 cities, educational institutions, and over 400 financial institutions have joined the ‘Race to Zero’, pledging to take rigorous, immediate action to half global emissions by 2030.

However, commitments made by governments to date fall far short of what is required. Current national climate plans – for all 193 parties to the Paris Agreement taken together – would lead to a sizeable increase of approximately 14% in global GHG emissions by 2030, compared to 2010 levels.

Getting to net zero requires all governments – first and foremost the biggest emitters – to significantly strengthen their nationally determined contributions (NDCs) and take bold, immediate steps towards reducing emissions now. The Glasgow Climate Pact is calling on all countries to revisit and strengthen the 2030 targets in their NDCs by the end of 2022 to align with the Paris Agreement temperature goal.

United Nations Secretary-General, Antonio Guterres, is also calling for further commitments at the forthcoming COP27 climate conference in Egypt, in November 2022, to deliver a global reduction of emissions by 45% by 2030 in order to reach net zero emissions by mid-century.

Figure 2. mWave features a series of air-inflated rubber membrane covered concave cells mounted to a structure below the ocean’s surface, creating an air-filled volume. To maximise energy capture, the structure is arranged at an angle to the incoming waves. As waves pass overhead, air is pushed out of each cell through a series of valves into a one-way air-duct. The cells are refilled once the wave has passed. The flexible membrane is made from industrial grade rubber. The longstanding use of similar materials in a range of marine applications has demonstrated the material’s reliability and longevity.

Global potential of wave energy

It is now possible to look to the oceans with hope and optimism on the race to net zero. The International Energy Agency (IEA) believes the sea offers a vast, untapped natural energy resource which will deliver 10% of the world’s electricity needs by 2050, equating to approximately £75 billion annual CAPEX investment into the market.

Up until now, the adoption of wave energy has been slow due to poor survivability of past wave technologies and a relatively high projected levelised cost of energy (LCOE) compared with other renewables. However, a new era has arrived for ocean energy, and Bombora’s pre-eminent technology has been carefully designed to address the survivability challenge, and is projected to be cost-competitive with other marine renewables and fossil fuel energy options in the near-term.

When effectively harnessed, wave energy has the potential to provide continuous power 24-hours a day, with much higher predictability than wind and solar. As well as increasing power output from seabed lease areas through combined wind and wave arrays, it also diversifies the renewable energy supply, reducing the need for storage whilst minimising any impact on the environment.

According to the U.S. Energy Information Administration, the waves around the US coasts could provide 66% of the country’s electricity. And as Bombora now prepares to deliver a powerful WEC in the UK, many other countries around the world are ramping up their interest and support in wave energy projects – including Australia, China, Denmark, Italy, Korea, Portugal, and Spain – amounting to a tidal wave of fresh interest in the sector, and a clear vote of confidence in its potential contribution to the future clean energy mix.