Energy Observer: From ocean runner to technological marvel


François Tregouet reports on Energy Observer, the former offshore racing catamaran converted into a “zero emission” scientific platform

Few boats have had such a rich and varied history over the past 40 years as this one, now known as the Energy Observer.

Nigel Irens and Mike Birch, the creators of the boat, would they still recognize it today? The slender arches of TAG formula, now Energy Observer, remain the identifying feature of this famous ocean racer, but much more has changed in the boat’s many lifetimes.

In 1983, the 80ft TAG formula was launched as part of a revolutionary new generation of multihulls designed for ocean racing and record breaking. At the time, it was the largest offshore racing catamaran of its type, built using aerospace technology. The following year, she broke the 24 hour record by covering 512.5 miles.

In 1993, she was purchased by Peter Blake and Robin Knox-Johnston for an attempt by Jules Verne, piloting a spinnaker decorated with bright red and green apples under the name ENZA (Eat New Zealand apples). The second attempt, in 1994, was successful and the boat set a 74-day crewed round-the-world record.

Then it became Alliance Royale & Soleil, skippered by Tracy Edwards. Although the Jules Verne Trophy proved elusive, Edwards and his team broke seven world records.

The Irens-designed catamaran was relaunched as Enza in 1993 for Peter Blake and Robin Knox-Johnston’s Jules Verne campaign, successfully taking five days less than the previous record. Photo: Ajax News / Alamy

Then Tony Bullimore took care of it, extending the hulls to 100 feet and running like Legato team to the race around the world organized by Bruno Peyron to celebrate the year 2000: La Course.

In 2010, off Cap Finistère, she capsized in 15 knots of wind. Many believed the boat would never recover from such an accident: too old to run, too damaged to repair.

A new purpose

However, French entrepreneur Victorien Erussard, who has sailed everything from Hobie cats and Formula 18s to Route du Rhum and Transat Jacques Vabre competitions, had a different idea.

Its goal was to build the first 100% energy self-sufficient ship. The frame of an old ocean racing catamaran would make the ideal platform, and the “recycling” of an existing boat perfectly matched the ambitions of the project.

The two Oceanwings developed by VPLP have a total surface area of ​​64m² and are 1.8 times more efficient than conventional sails and rigs. Photo: Productions Energy Observer

Since Energy Observer was launched in 2012, the project is constantly evolving and has so far covered more than 30,000 miles.

the Energy Observer The team believes that to be feasible as a truly zero-emission boat, capable of sailing from the Arctic Circle to the equator, the ship requires a mix of energy sources. The diversity of sources improves “reliability, performance and safety,” notes Louis-Noël Viviès, general manager of the project.

The main propulsion on board is provided by two 45 kW electric motors. These are generous in size and are not used at their maximum capacity, so they offer high efficiency. Opting for a single bank of batteries capable of powering them over a long period without recharging would have sent the project into a downward spiral in terms of weight. Instead of, Energy Observer has two smaller battery banks, with a combined total of 100 kW, which is also safer.

This hybrid solution still weighs 1.4 tonnes. In the future, with lighter batteries in development, this weight should be halved for the same capacity.

The batteries act as a buffer between the motors and the four different energy sources necessary to guarantee a 24/7 power supply. The most innovative of them is undoubtedly hydrogen.

Developed in partnership with Toyota, the two hydrogen fuel cells are capable of producing 10 times more energy than on-board batteries for the same weight, almost indefinitely. Photo: Productions Energy Observer

The battery was developed by the project partner Toyota, from the one used in their hydrogen car, the Mirai. “It provides 10 times more energy for the same weight as the other on-board batteries,” specifies Viviès. There are two hydrogen batteries, one in each hull, with a peak power of 80kVA.

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Although they are now three times cheaper than the first generation batteries originally installed, hydrogen batteries still cost twice the price of a generator of the same power. On the other hand, they are guaranteed for 80,000 hours, without maintenance, and have no associated fuel cost, since Energy Observer manufactures (by desalination, purification then electrolysis) and stores its own hydrogen from seawater in eight 64kg tanks.

Battery efficiency is 2.5 times that of diesel when you consider the energy required to extract, refine and transport it to the pump. The battery also generates 50% of the heat used on board, so the crew never ran out of hot water and were able to enjoy a warm and comfortable interior during the boat’s journey north to Spitsbergen.

An iguana swims under the large superstructure added to the original racing hull to support additional solar panels. Photo: Productions Energy Observer

The third source of energy consists of solar panels, which cover 202 m² of surface area and deliver a cumulative power of 35 kW. Solar panels use different technologies depending on their location on the deck or superstructure.

Some are double-sided to capture the rays reflected from the surface of the water. Elsewhere, they’re coated with a non-slip polymer that improves performance when the sun is not at its peak.

Wind power is an area that has evolved a lot since the launch of Energy Observer. After experimenting with vertical wind turbines and a traction wing, the catamaran now carries two Oceanwings, 32m² rigid wings developed by VPLP and inspired by their lessons from the America’s Cup.

Oceanwings are made from Hydranet, a sailcloth woven from Dyneema, and slide along the masts to reduce the sail. Photo: Productions Energy Observer

Oceanwings were developed with the ultimate goal of making maritime transport less polluting, and Energy Observer is an ideal experimentation platform to develop the system.

Almost twice as efficient as traditional sails, the wings can be used to increase speed or reduce power consumption in addition to electric motors. The wings also allow Energy Observer to use its fourth source of electricity production, hydrogenation from the propellers when the wind is favorable.

Adapt and refine

The basics TAG formula hull platform was light, just 15 tons. Although the catamaran no longer wears its original rigging, batteries, engines, etc. additional increased final displacement to 30 tonnes. It was therefore necessary to increase the buoyancy of the hulls, obtained by grafting on a second skin, adding volume below the waterline.

In addition to adapting all of these emerging technologies to the corrosive marine environment, the expertise of the Energy Observer team lies in the fine management of these different energies, optimizing yields.

During the coastal passages, Energy Observer made an average speed of 4.5 knots, but 6.34 on a transatlantic, with peaks at 10 knots. Photo: Productions Energy Observer

This ranges from selecting the most efficient mode of propulsion or power generation at a given time, to fine-tuning the wings or the pitch of the propellers.

With any innovation there is often a big leap from theory to practice, but the project creates the data to prove the concepts.

Energy Observer has been traveling the world’s oceans since 2017. In March 2020, he embarked on his final voyage, which will include the Tokyo Olympics and the Dubai World Expo in 2021, before returning to Paris for the 2024 Olympics.

Of the 2,134 miles traveled so far on the current trip, it has reached average speeds of 6.34 knots, with 83% of the energy produced being used for propulsion or navigation, and only 17% for systems. servants used by the crew of five on board.

In the last eight months, solar represented 56% of on-board production, hydrogen 7% and Oceanwings 37% of the equivalent consumption of the engines saved.

Hydro-generation has been little used in intertropical latitudes, but should be used more in windier regions.

Energy Observer Specifications:

Length: 30.50m 100ft 0in
Beam: 12.80m 42ft 0in
Rough draft: 2.10 m 6 feet 11 inches
Shifting: 30 tons
Sail surface: 64m² 700pi²
Designate: Nigel irens

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