What did we learn from Energy Observer’s round-the-world renewable energy voyage?
On 14 June 2024, Energy Observer completed her round-the-world voyage and arrived home to St Malo, seven years after setting sail. The Energy Observer laboratory vessel is the world’s first autonomous vessel to navigate the oceans using a mix of renewable energies and hydrogen produced on board from sea water.
Founded by Victorien Erussard, a merchant marine officer and offshore sailor, Energy Observer sailed the globe with the aim of championing the sharing of knowledge and sustainable solutions for the future of our planet. Erussard gathered a team of sailors, scientists, engineers and journalists to travel onboard during the voyage and trials.
Over the course of Energy Observer’s 68,000 nautical miles voyage, the latest cutting-edge technologies – hydrogen, batteries, solar and wind power – have been tested to breaking point, and optimised, with the support of several manufacturing partners.
Erussard talks to MIN about this ground-breaking project and how Energy Observer has laid the framework for sustainable marine and green power across the globe.
Which sustainable technologies worked onboard and which didn’t make the grade?
The OceanWings
VE: As a first prototype of this technology at this scale, the OceanWings brought few challenges in terms of integration and implementation. However, the concept itself has been validated with great success.
When only using the sails as propulsion, Energy Observer reached a peak speed of 16.6 knots and often steadily maintained 8-9 knots with 25 knots of apparent wind with the right angles. For 62m2 of sails and for a 34-ton boat, that’s a very good result, even above expectation. The small area of sails and their vertical position allowed for a very limited shading impact on the boat’s photovoltaic system which remained the main input of energy for the control and life onboard.
The vertical wind turbines and kite propulsion system
VE: Prior to the installation of the OceanWings in 2019, two other technologies had been tested for wind energy:
• The vertical wind turbines, converting wind power into electrical power
• A kite system, for direct propulsion, converting the wind power directly into movement of the boat
These two systems were not kept on the boat. In the case of the vertical wind turbines, the energy balance of the turbine was not positive. When the apparent wind was from the front of the boat, the wind turbines turned well but the electrical power needed to supply the electrical motor to overcome the loss of speed caused by the drag was superior to the electrical power converted by the wind turbine. When the wind was from behind, they actually worked almost as sailing, which was causing drag in the other way and pushing the boat. But the apparent speed of the wind was in consequence low and the electrical production was not as good as expected.
As for the kite system, after a few tests, the technical team concluded that the prototype was not ready in terms of autonomous use.
Variable pitch propellers
VE: In 2019, after the installation of the OceanWings, variable pitch propellers replaced our classical propellers in order to limit the drag when using the sails only. They actually provided a very good solution for this purpose. However, they decreased the capacity for hydro-generation using propellers as hydro turbines. It was a compromise to prefer sailing to hydro-generation.
Toyota fuel cell
VE: The Fuel Cell was installed in 2019 and is the result of collaboration between Toyota Motor Europe and EODev teams. This work led to the development of the electro-hydrogen generator GEH2, the flagship product of Energy Observer Developments | EODev, which is now one of the world leaders in this field.
Integration optimisations have been made over the years in response to initial feedback. With output power set at 30kW, the system’s electrical efficiency is 58 per cent. This fuel cell is highly reliable, and shows good efficiency and behaviour, even in rough seas. The heat exchange interface developed by the technical team of Energy Observer also allowed for the use of the cell for heat usage for onboard use (air and water) as a by-product of the electrical supply from the hydrogen.
Hydrogen production and storage
LONDON, ENGLAND – OCTOBER 04: The future of renewable energy solutions sails into London
The Energy Observer, in 2019 as part of its world tour. Photo courtesy of Lloyd Images/Energy Observer.
VE: On the hydrogen production part of the system, the electrolyser has been very reliable and didn’t require any curative maintenance. However, the two compressors used to increase the pressure of the hydrogen from 30 bar (hydrogen pressure at the output of the electrolyser) up to 350 bar (pressure of the hydrogen in the tanks when they are full), were the weakest link in the chain. They required lots of adjustments in the early years of the project after many membrane failures. These failures were never completely overcome but the adjustments made allowed for fewer issues. It was nothing dangerous but limited the hydrogen production time.
How will the innovations tested onboard trickle down into the leisure marine and commercial sectors?
VE: Feedback to Solbian, our photovoltaic solar panel technical partner, allowed for the evolution of its products. We tested different types of panels, in diverse and harsh conditions (high temperature, high humidity, lots of people walking on the panels, etc.),
By being the first vessel to use OceanWings at this scale, Energy Observer provides proof that this concept is efficient and therefore is a promising technology for wind propulsion in the marine sector.
Feedback on usage and data were made to the OceanWings provider, Ayro and the technology has since been adapted for a commercial marine vessel, La Canopée, and for another project in the leisure marine sector with the Zen50 vessel.
Jérôme Delafosse, Geneviève Van Rossum, Kitack Lim, Francesco La Camera, Victorien Erussard, onboard the Energy Observer in London on its 47th stopover, the final in 2019 as part of its multi-year world tour. The vessel was nominated as the French ambassador for the UN’s 17 Sustainable Development Goals. Photo courtesy of Lloyd Images/Energy Observer.
The use of the Toyota Fuel Cell on-board has been the starting point for the development of Energy Observer Developments | EODev REXH2, a marine compliant integrated fuel cell system using Toyota Fuel Cell technology.
A few boats are already equipped with the REXH2 in the leisure and competition marine sector (Hynova, Fastboat America’s Cup, Fontaine Pajot) and more projects are expected to rollout in the commercial marine sector, as auxiliary electrical power supply from hydrogen or even as the main source of power in the case of the Energy Observer 2 cargo project.
We wouldn’t advise having a full production hydrogen chain onboard as it’s too complex and it’s not the most efficient way of producing and using hydrogen. But for Energy Observer it was actually necessary as hydrogen was not available to refuel at stop.
Why does hydrogen energy polarise the renewable energy debate?
VE: The debate between renewable energy (or better, electrification) and hydrogen occurs when we mistakenly and simplistically think of the two as rivals.
On the one hand, hydrogen has been gaining momentum in recent years as a clean energy vector: it burns cleanly, it is incredibly versatile and has the best energy density in terms of mass. But as any energy it comes with some challenges:
• About 95 per cent of it is currently produced by steam methane reforming – a very polluting process
• Converting hydrogen into electricity is less efficient than using electricity directly through batteries (the efficiency of producing green hydrogen and reconverting it to electricity is about 25 per cent, versus more than 95 per cent for Li-ion batteries)
• The production, storage and distribution infrastructure is still lacking and this holds back large-scale adoption and makes it much more expensive than batteries
On the other hand, with electrification, batteries are an obvious solution for energy storage. Their price has dropped significantly, and their capacity has improved.
Yet, there are some hurdles to overcome too: their performance degrades over time (which limits their long-term storage capability), recycling processes are still under development, and ethical concerns arise regarding the mining of cobalt, a key component, particularly in the Democratic Republic of Congo, where mining practices like child labour occur.
Electrification is indeed already well-established, and it is efficient, but electrification is not a panacea. Rapidly expanding renewable energy and electrifying as many sectors as possible is the fastest and most cost-effective path to decarbonisation.
Electric is a clear choice for most applications, especially light duty vehicles and low-temperature heating in buildings and industry. However, hard-to-abate and hard-to-electrify sectors such as aviation, shipping, fertiliser production and long-term storage are not practical and too expensive to electrify.
There’s where we need hydrogen. Hence, electrification and hydrogen are not competitors but are largely complementary. Instead of focusing on one technology over the other, we should embrace both because the polarisation between these two only slows down the pace at which we can solve the climate crisis.
What has the Energy Observer project proved when it comes to hydrogen power?
VE: The primary goal of our project was to demonstrate the feasibility of using a mix of renewable energies onboard a vessel for self-sufficiency. While hydrogen is a very important part of the mix, offering long-term energy storage, it’s not the sole focus.
Our voyage served as a real-world testing ground for hydrogen technologies at sea. By submitting them to harsh conditions we demonstrated the technical viability and the environmental advantages of hydrogen as a maritime fuel.
The potential of hydrogen goes beyond powering smaller vessels: its scalability and versatility make it an attractive option for a wide range of maritime applications – from ferries to cargo ships, yacht and pleasure crafts – but also for land applications.
In fact, the benefits of using this molecule in a fuel cell – namely an electrochemical device that uses hydrogen as a fuel to generate electricity through chemical reactions – are diverse:
• No GHG, NOx, Sox or PM are produced. The only resulting product from this reaction is water, and if the hydrogen itself is produced from renewable electrolysis of water (as we do onboard Energy Observer), the well-to-wake process does not produce waste, making it an attractive alternative for generating low-carbon electricity
• Hydrogen fuel cells result in quieter operations than traditional power sources
Yet, challenges need to be overcome before hydrogen can be democratised onboard ships.
While it has a very high specific energy density (1kg of hydrogen contains three times the energy of 1kg of diesel), which spares weight, its volumetric energy density is very low, making it bulkier to store. A challenge naval architects and engineers are trying to face.
In conclusion, it is necessary to federate all efforts – from governments to industrial players, from researchers to the public – to address these challenges. By making green hydrogen production more affordable, building the necessary infrastructure, improving the technology, creating supportive policies, and fostering public trust, hydrogen can become a key player in achieving a clean energy future.
This article was originally published in Marine Industry News magazine.
Images courtesy of Energy Observer, unless otherwise stated.
The post What did we learn from Energy Observer’s round-the-world renewable energy voyage? appeared first on Marine Industry News.
