Futuristic sailing ships enable production of green hydrogen at sea

The British start-up DRIFT Energy’s sailing vessel is reminiscent of science fiction from the turn of the last century. But whereas those old visions of the future envisaged rotating blades propelling the vessels forward, DRIFT does the opposite – the blades are used to capture energy.

The vessels, which are scheduled to be built from 2027, are 60-metre-long catamarans equipped with hydro turbines and an on-board hydrogen production facility. As the vessel moves forward, the turbines spin and generate electricity, which is converted via electrolysis into hydrogen. The hydrogen is then delivered to ports around the world as a fuel or energy source. DRIFT’s proprietary routing software, called GOLDILOCKS, constantly searches for the right conditions to create an optimised route. Wherever the right wind and lowest waves are found, that is where it sails.

"Most people agree that the world needs more renewable energy. There are several advantages to our solution. Firstly, we are not connected to the grid, so we have no grid constraints. In the UK, there is a waiting list of around 8 years to get a grid connection. We can sell a vessel directly to anyone who wants to start generating green energy", says Dylan Binding, Senior Performance and Dynamics Engineer at Drift Energy.

Found RISE through a research report

The hydro turbines are a crucial link in the energy production chain for DRIFT Energy’s solution. Magnus Wikander, who is responsible for strategic development in maritime hydrodynamics at RISE, describes the challenge as follows:

"A standard turbine, such as a propeller on a boat, takes energy from an engine and pushes it into the water so that the boat moves forward. DRIFT Energy’s turbine is designed to do the opposite – it is intended to capture energy to store it as hydrogen, but without capturing so much energy that the vessel cannot sail at high speed. To achieve this, we need to understand how water flows around the turbine blades."

Dylan Binding points out that there are few examples of underwater motion driven turbines in operation today, and just as few people with experience of the technology. However, some of this rare expertise can be found at RISE. RISE has been conducting research into underwater systems – ranging from propellers to underwater vehicles – since 1940. Many of the findings have been published in scientific journals, which has highlighted the resources within the maritime sector to an international audience. Among them is DRIFT Energy.

Simulations – A key tool for turbine optimisation

DRIFT Energy benefited from RISE's expertise in CFD (Computational Fluid Dynamics) analysis and turbine modelling to quickly begin testing designs in DRIFT’s proprietary simulation suite. Their models simulate the entire vessel's performance based on approximately 3,000 performance parameters and millions of simulated kilometres sailed in GOLDILOCKS.

"Interestingly, this work also raised several questions about how the underwater turbines could be best used", says Dylan Binding.

During the simulations, it became clear that DRIFT Energy can achieve certain operational benefits by selecting times when the turbines’ capacity should be maximised, and when it should not. In marginal conditions, running the turbine in “sub-optimal” configuration can lead to a global performance gain, and the energy yields in this regime are extremely sensitive to how you design the vessel and turbine together.

"Marrying the turbine’s performance with the vessel design was another area where RISE was of great help. We had a great deal of confidence in their expertise from the very beginning, which meant we could focus on our other challenges. We had time to focus on difficult problems to solve like the hydrogen plant, GOLDILOCKS routing algorithm and global performance optimisation, as we trusted RISE to handle the shaping of the turbine", says Dylan Binding.

“Has achieved tangible performance improvements”

The turbine, which was designed in collaboration with RISE, is now part of the final design for a vessel capable of producing more than 100,000 kilograms of hydrogen per year.

"The turbines are one of the most important components on the ship. They form one of the first links in the energy chain, so any improvements made there have great returns in terms of efficiency. For us, the collaboration with RISE has led to a return on investment, which ultimately affects how much energy we can supply and how much good we can do for the planet."

The partnership also brings other benefits for the British company. 

"When we’ve spoken to people outside the company and told them about our collaboration with RISE, they’ve raised their eyebrows. It’s an impressive partnership. We have achieved tangible performance improvements and established a professional relationship that we hope to benefit from again in the future", says Dylan Binding.