A new ship project in the Philippines, a Bangka, hopes to represent a low carbon alternative, working powered by the waves. The ship is a hybrid model, which uses multiple internal combustion engines for initial propulsion but switches to wave energy during the open water cruise.
The trimaran (or Bangka, as it is called) is a common sight on Philippine waters. The country took advantage of this project already in its first warships, so it adopted it for its traditional sailing boats and fishing boats. As an island nation, the Philippines rely on boats, ferries and merchant ships to transport people and goods across its over 7000 islands. But its fleet of merchant and passenger ships is one of the country's largest contributors to greenhouse gas emissions. In 2012, transportation was the second largest source of greenhouse gas emissions in the Philippine energy sector, after heating and electricity.
Globally, 9% of all transportation emissions come from international and coastal shipping. This is a small figure next to 72% coming from road transport, but it puts transport on a level similar to aviation, which constitutes 10,6% of emissions transport. And with the volume of world maritime trade that is expected to increase from 3,8% per year to 2023, emissions from the maritime sector are also likely to increase.
Unless the growth of maritime traffic cannot be dissociated from emissions.
Power of the sea
This project was born from an idea of Jonathan Salvador, maritime engineer and owner of the shipbuilding company Metallica Marine Consultancy, Fabrication and Services. Jonathan was immediately inspired by the traditional bangka design. "The task of stabilizers is to provide stability so that the bangka does not tip over laterally", says Salvador. “But I also noticed that every time a wave hits the stabilizer, it constantly reacts to the up and down movement of the wave. What if we could convert this reaction, I asked myself, into electricity? "
The way the wave energy works will be familiar to anyone who has roamed the sea. Sometimes they are strong enough to push you to shore or high enough to push you further. The hybrid trimaran has a wave energy converter in the form of hydraulic pumps integrated into its stabilizers. As the pumps move through the waves, they collect the momentum of these waves, converting their kinetic energy into electrical energy. This energy will go to feed a generator that will supply electricity to the ship. The more waves the trimaran encounters, the greater the power it can produce from those waves.
Bangka, the genesis
Construction of the hybrid trimaran begins in 2018 and is completed in early 2020. A typhoon in 2019 delays the project, and the quarantine for Covid-19 has stopped it for a while. Despite these difficulties, the team aims to finish building the ship by the end of 2020, with a three-month sea trial scheduled for the first quarter of 2021. The ship is expected to be able to carry 100 passengers, four vans and 15 motorcycles.
It is hoped that the wave propulsion boat prototype will be the first of a series of increasingly ambitious projects that move away from fossil fuels.
The use by the hybrid trimaran of wave energy could be a significant step towards reducing the need for environmentally harmful fuels such as diesel in the Philippines. And with the wave energy that compensates for the use of gasoline, Salvador and his team aim to reduce the ship's carbon emissions one third compared to the most modern large-scale shipping lines.
The trimaran has the ideal shape
The wave energy converter benefits from the traditional Bangka trimaran design. "Wave energy requires movement of one part of the system relative to another," he says Rob Cavagnaro, mechanical engineer at the Marine Sciences Laboratory of the Pacific Northwest National Laboratory in the USA. "Having stabilizers that can be raised relative to the central hull may be suitable for this purpose."
In addition, the waves are dense with energy: they can be really powerful. On the coast, waves can reach power densities of 60-70 kilowatts per meter in areas with deep water. In the United Kingdom and the United States, for example, the average power density of waves is between 40 and 60 kW per meter. If you can translate that energy into other useful forms, you can do a lot with very little.
The challenges to face
Converting movement into energy efficiently can be a challenge. "There can be many leaks along the way, from friction in hydraulic systems to heat in the electric generator," says Cavagnaro. The engineering challenge that remains is to minimize these losses. Another obstacle would be the design of a wave energy converter small enough for the size of the ship. Wave energy converters generally develop more power than they are large, but if they are so large that the waves cannot move them, they cannot actually gather momentum.
Nonetheless, a private company in Boracay, a popular tourist island in the country, has already expressed interest in operating the ship once launched, he says Rachel Habana, senior scientist at the Philippine Council for Industry, Energy and Emerging Research and Development Technology, who oversaw the development of the trimaran. "We imagine that the future of public shipping in the Philippines is safe and green with fewer emissions, and we see the trimaran bringing that vision to life," he says.
Between saying and making a Bangka there is the sea
So far, I don't forget, the hybrid trimaran is still a prototype. "Since we have new technologies for the boat, we need a phase of technological verification before we can proceed with large-scale marketing," he says Yasmin Tirol, leader of the project. "We have already conducted some test models for the wave energy converter, but we need to examine its actual performance and optimize it."
Cost is another problem. Funding for the project is 76 million Filipino pesos (1,5 million euros), but Salvador estimates that commercial costs reach the equivalent of 5 million or more per ship. To keep expenses low, at least 80% of the parts of the trimaran are locally sourced, and the entire production and assembly process is performed within the country.
The current one is a "series one" prototype. More ambitious and less expensive series should follow, with the wave energy used to power the ship almost totally or totally. True, the stronger the wave, the more energy there is, but no one likes to surf at full speed in the midst of storms. Wave energy ships are a nascent technology, and the best way to draw energy from the sea is yet to be seen.
