AC-DC power switch cuts ship fuel use by up to 25%

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Fuel savings on ships can come from many sources. Ship's paint can prevent barnacles from attaching to the hull and creating drag. Reducing speed by half can generate 30% fuel savings. And some operators have even been experimenting with kite sails to augment their diesel engines with wind power.

Now Business Green is reporting that engineering giant ABB is claiming up to 25% fuel savings from changing how ships generate and distribute electricity onboard:

The Swiss company announced this week that it has completed trials of its DC energy distribution system, called the OnBoard DC Grid, on the Dina Star, a 93-metre long, 5,000-tonne multipurpose supply and construction ship. Ships typically use alternating current (AC) systems to distribute power from diesel generators to key electrical components such as propulsion systems. However, one disadvantage of AC is that the generator engine must be kept running at a constant speed to provide a steady voltage to components around the ship. In contrast, installing a DC distribution system allows the diesel engines to run at variable speeds, according to the power required by the ship's electrical system, leading to reduced fuel demand.

Initial projections suggested fuel savings would be 25%, but initial trials on the Dina Star actually resulted in a 27% reduction.

AC-DC power switch cuts ship fuel use by up to 25%
Changing how ships generate onboard power can have a significant impact on overall fuel use.

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