27 February 2018
Diesel Electric propulsion – Q & A
Over the last few years we have seen a dramatic increase in the acceptance of Electric technology, largely driven by growth in the automotive industry. Clients are increasingly knowledgeable about the Diesel Electric system although there are multiple questions which come up repeatedly in early discussions. We will look at some of these questions in this and forthcoming issues of Logbook.
1. Why does WIDER believe that Diesel Electric propulsion and the Direct Current (DC) grid solutions are the future?
Fundamentally, because Diesel Electric offers numerous advantages over the traditional system which, due to advances in production, are now readily available for yachts starting from 40m. The choice of DC grid – WIDER are the first builder of yachts to include this system although others have used AC grids and are now following suit - was based on a thorough consideration of the specific power requirements for yachts in this size range, from very low usage at night time at anchor, c. 50kW, through to high usage while steaming at full speed, cooking lunch for guests & crew with air conditioning on max, c.1200kW.
Generators convert mechanical energy (supplied by a diesel engine) into Electrical energy. The DC system involves running generators at variable speed (by adjusting the RPM of the diesel engine) and hence the output of electrical energy. Variable speed generators thus allow us to produce electricity to cater for the specific demands of the yacht at any given moment, no more no less. By contrast a standard generator will run the diesel engine at fixed RPM producing fixed output of power, ie they are binary: either ON or OFF, necessitating the inclusion of load banks to ensure smooth operation. These are essentially very inefficient given that the maximum power is produced irrespective of the specific power demands from Hotel & propulsion at the time.
The DC system ensures for a very efficient performance of the generators meaning savings in fuel consummation but also, more importantly, in terms of reduced noise and vibration and increased time between overhauls on the machinery (meaning reduced ownership costs). These are all qualities - readily available in their house and in their choice of cars - which appeal to the modern yacht buyer.
The WIDER 165 is currently in build and available for sale at €30m euro. She is scheduled to be launched in the Spring of 2018, with final delivery in time for the summer. See here for latest update.