More ‘natural’ approach manages propeller pitch to meet energy efficiency requirements, rather than needing costly engine derating or torque control
Bulkship Management, the Oslo-based ship manager with a specialty in geared vessels, has confirmed a significant contract to implement BERG Propulsion’s straightforward ‘EPL for EEXI’ power limitation solution across 10 ships trading in US Gulf and Caribbean waters.
Submitted to the class for approval, the new Berg Engine Power Limitation solution is of particular benefit to the many ships whose performance requires only moderate adjustment to meet IMO Energy Efficiency for eXisting ships Index (EEXI) needs. In force from January 1, 2023, EEXI means owners must verify that a ship’s attained energy efficiency matches its ‘required EEXI’ by its first subsequent survey.
Rather than using a governor for engine derating or ShaPoLi (shaft power limitation), Berg’s innovative EPL (engine power limiter) is a software-based solution which works with the supplier’s MPC800 control system to limit propeller pitch. Requiring no additional sensors, signals are sent by the BERG EPL to the ship’s controllable pitch propeller (CPP), where brake torque is reduced until the engine power reaches its approved range. The information can be used to verify that attained EEXI matches required EEXI, once entered into the IMO’s data collection system (DCS).
A pilot technical assessment of the 8,036 DWT Bulkship vessel Oslo Bulk 6 indicated that EEXI needs would be satisfied by derating its main engine to comply with the new regulations. Sea trials covering the BERG EPL’s limiting effect on the ship’s BERG MPP950 CPP brought DNV acceptance of the system’s performance as an effective EPL solution. Bulkship has now confirmed orders to install across nine more ships.
“On a CPP installation, it is more natural to limit the engine power output by the accurate governance of the propeller than by limiting the engine rpm setpoint,” said Magnus Thorén, Sales Manager Energy & Efficiency, Berg Propulsion. “We use the main engine signal interface to limit the brake torque created by the propeller. Although it’s for a different purpose, this is based on the well-established practice of using a propeller pitch setpoint for overload protection.”
Using the Berg EPL, crew are at liberty to override the function in cases where full power is needed on a password-protected basis, although exceeding the pre-set limit would result in automatic logging for later reporting purposes, said Thorén.
“Our newly released EPL adds to our growing portfolio of novel automation solutions integrated in our MPC800 control platform,” commented Jonas Nyberg, Managing Director – West, BERG Propulsion. “We are continuously developing new software solutions for our existing MPC800 control system, leveraging the platform already installed in the world fleet. Solutions include fuel optimization systems, hybrid controls and now EPL, among others.”
All 10 of the Oslo Bulk ships concerned feature Berg’s MPC 800 control system solution, which is required as a starting point for the BERG EPL solution. However, Thorén disclosed that the solution’s effectiveness had encouraged one buyer already upgrading its ship control systems to MPC 800 control to specify that BERG EPL for EEXI should also be included.
Berg Propulsion is a Swedish company providing a range of propulsion technologies, electrical integration solutions and energy efficiency optimization strategies for marine and offshore vessels. It designs and manufactures controllable-pitch propellers, azimuth thrusters and transverse thrusters, as well as vessel control and manoeuvring systems, and supplies both hybrid interface and integrated hybrid electric propulsion solutions.
Berg Propulsion has production facilities in Sweden, and direct sales & service offices in China, Singapore, Türkiye and United Arab Emirates. Furthermore, the company is supported by a global dealer & service network.