Exploring energy efficiency

On March 28th, the Yacht Club du Monaco hosted La Belle Classe Superyachts Environmental Symposium, chaired by the Club’s Secretary General, Bernard d’Alessandri. Attended by more than 50 guests that included yacht owners, designers, brokers, suppliers, builders and other select industry representatives, the theme of the dinner-debate was the superyacht industry: can energy efficiency and comfort on board go hand in hand? Special attention was paid to reducing energy consumption while berthed in marinas, a subject of particular relevance to the port of Monaco. The timing of the debate was especially appropriate, as the solar-powered vessel Planet Solar was due to arrive in Monaco after completing its global circumnavigation.


The opening presentation by chief mate Michael Zerr, staff captain aboard 105m Lady Moura, was the most revealing and set the tone of what was a stimulating – and at times passionate – discussion. Michael highlighted the fact that the largest single energy consumer while in port is the HVAC system, which usually relies on diesel generators. During the winter season the yacht is berthed in Palma de Mallorca where it can draw electrical power from its own land-based transformer station, consuming 1000-1500 amps of electricity per day for a total of around 990,000 kW/hrs over a three-month period. But over the course of the year, Lady Moura’s four generators are fed around 1500 tonnes of fuel, which equate to a cost of over one million euros.

“Lady Moura is over 20 years old and some newer yachts have energy-saving technologies such as recycling exhaust gases to provide hot water,” Michael pointed out. “But on the whole, I don’t think vessels of similar volume have significantly lower energy costs. For a yacht of 6000 gross tons, 2000 amps per day is representative.”

Michael’s sobering statistics served to present the scale of the challenge, which is multiplied many times over in the summer season, especially during events such as the Monaco Yacht Show when up to 100 superyachts might be berthed in the marina, each relying on diesel generators to supply air conditioning and other hotel services.

German eco-industrialist and yacht owner Guido Krass is founder of the Hanseatic Marine yard in Western Australia, which he set up specifically to build the Silver series of superyachts designed by Espen Oeino (also present at the evening debate). These long, slim-hulled vessels go against the trend for high-volume, beamy boats, providing high speed while reducing fuel consumption by maximising hull efficiency. Krass reminded the audience that his business background is in green energy and joked that perhaps owners should consider buying a sailboat and travelling by train if they really want to be eco-friendly. “More seriously,” he continued, “I love motoryachts and Silver was built to be energy efficient from the hull up, and this premise has made all the difference.”

Krass confirmed that diesel generators represent a significant portion of the onboard running costs, especially as the yachts he has owned were rarely in port long enough to switch to shore power. With this in mind, he downsized from 235kW gensets on the original Silver to 165kW on Silver Zwei and the third in the series, M/Y Smeralda – more than enough for daily hotel needs and anchor operations, with the third generator only kicking in during manoeuvres with the bow thruster and other peak periods. Moreover, he attempts to maintain AC at reasonable temperature levels, perhaps by opening doors and windows for natural ventilation. The result is an annual energy bill that is significantly lower than the crew wages and, depending on the mileage, might be as low as 20 per cent of the total budget. But the main problem that Krass identifies is a lack of genuine innovation in the superyacht industry. “Compared with the construction industry, there are very few efficient AC solutions available for yacht building,” he points out by way of example. “We’re looking into the latest innovations, but it’s not always easy to gain Flag or Class approval for new equipment.”

The full article will appear in Issue 2 of The Superyacht Owner magazine, out in May.

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