Piston less Power for LNG Fuelled Mega Box Ship


Piston Less Power For LNG Fuelled Mega Container Ship


A technical and feasibility study was released by GTT, CMA CGM (and its subsidiary CMA Ships) and DNV GL for a new mega container ship today – the Piston Engine Room Free Efficient Containership PERFECT.

The concept vessel will be

  • LNG-fuelled
  • Powered by a combined gas and steam turbine
  • Electrically driven.

The new propulsion concept combining the above criteria has the potential to offer a more efficient, more flexible and greener box ship design than current 20,000 TEU two-stroke diesel engine driven ultra large container vessels.

The advantages are:

  1. LNG enables the implementation of new propulsion concepts as demonstrated by the PERFECt design.
  2. It can increase a vessel’s efficiency
  3. Reduce fuel consumption
  4. Offer a cost-effective solution
  5. It will also increase the utilization of LNG as ship fuel over the next few years

The COGAS, which is a system for combined gas and steam turbine power generation, has the fuel-to-power efficiency ratios higher than conventional diesel engines, which can achieve up to 52 per cent.  A modern, land-based combined cycle LNG-fuelled power plant will reach of up to 60 per cent as the power density by volume and weight is much higher for a COGAS system.

“CMA CGM and its subsidiary CMA Ships position themselves as pioneers by contributing to this worldwide leading innovation by  rethinking the ship’s design.  The lower footprint of the machinery system and increased flexibility of the electric propulsion system increase the capacity of the vessel, despite LNG tanks requiring more space than traditional fuel oil tanks, thereby generating greater revenues and reducing the payback time for the additional CAPEX required.”

“Gas turbines associated with steam turbines are ideal for the efficient utilization of LNG as a fuel.  This new design saves even more cargo space compared to a conventional design,” says Arthur Barret, LNG Bunkering Program Director at GTT.

The two 10,960 m³ LNG fuel tanks are located below the deck house, giving the vessel enough fuel capacity for an Asia/Europe round trip.  With the gas and steam turbines integrated at deck level within the same deck house, the tanks  increases the cargo capacity significantly.

The dissociation of electric power generation from electric propulsion allows a great deal of flexibility dispensing with the engine room.  The three electric main motors, which are arranged on one common shaft, can be run fully independently of each other providing increased redundancy and reliability and a high level of safety.

The gas turbine-driven power production and the electric propulsion simplify the ship’s machinery systems leading to new maintenance strategies seen in the aviation industry.  It reduces the ship’s engine crew dramatically and save costs.  The next phase of the study aims to optimize the propulsion system and ship design to attain even greater efficiency and increased cargo capacity.

Source: DNVGL


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