Study: Feeder Containerships Ready to Benefit from Hybrid Power Systems

Container feeders, with their frequent port visits and increased time in port, are ripe for efficiency gains through the use of hybrid power solutions, Hans Anton Tvete, DNV GL, believes. 

Hybrid power systems often achieve significant efficiency gains and emission reductions in operation modes in which a ship’s power demand fluctuates, for example when major energy consumers, such as cranes or thrusters, are utilized. This typically happens in connection with port visits.

A review of historical AIS data showed that container feeders are a ship type meeting this requirement, and thereby are potentially a good case for hybridization, according to a new study conducted by MAN Energy Solutions, Corvus Energy, and DNV GL.

What is more, as the feeder fleet is aging, new ships are likely to be ordered in the future.

Speaking at the CIMAC conference in Vancouver recently, Alexander Knafl, MAN Energy Solutions, presented the results of the study which examines the potential of hybrid power solutions in light of tightening regulations on greenhouse gas (GHG) emissions.

The study, entitled HYCAS, examines the cost effectiveness of hybrid power solutions on a 1,700 TEU container feeder vessel. The vessel design used for the study is Neptun Ship Design’s CV Topaz.

The pressure is on for the world to reduce its GHG emissions to avert a climate crisis. The IMO has set the maritime industry the ambitious task of reducing shipping emissions by 50% by 2050, as compared to 2008.

To work towards this challenge, the trio studied the potential of using batteries in a container feeder vessel, to assess if it is possible to both reduce emissions and save operational costs.

“There were several factors that went into the selection of a container feeder vessel for the study. We were looking at where hybrid systems could offer significant efficiency gains, which pointed to operational states with fluctuating power demand. This typically occurs with large consumers such as cranes, pumps, ventilation fans, or manoeuvring equipment, especially in port,” Tvete explained.

“Focusing on a container feeder vessel we were able to generate a typical propulsion power profile from vessel speed data, as well as an artificial time-resolved electrical load profile from the according electrical load table… Together with the specific battery and engine characteristics, it is possible to optimize the size of a battery in a hybrid propulsion system for the 2020 and 2030 scenario as an optimum of additional CAPEX and OPEX savings,” Carina Kern, MAN Energy Solutions, added.

The study explored two main scenarios, a vessel built in 2020 with a 500kWh battery system replacing one genset used for peak shaving and as a spinning reserve, and a vessel built in 2030, using a much larger 11MWh hybrid system for zero-emission port entry and exit.

Under the first scenario, with the hybrid power train resulting in an approximately 13% total cost for the vessel, payback times are as low as two to three years. However, the larger system increases the costs of the vessel significantly, meaning that only with a combination of lower prices for the battery system and higher fuel costs than today would the system be economically attractive.

“It is our hope that these study results will increase cargo shipowner confidence in seeking out new energy solutions, as a good economic rationale already exists for supporting auxiliary loads with a hybrid configuration,” Sean Puchalski, Corvus Energy, pointed out.

“As for the future propulsion scenario, perhaps we will not have to wait until 2030. We are already seeing strong demand for high capacity energy storage systems in passenger vessels. With the right leadership from cargo owners, we may see this translate to the merchant sector sooner than later.”

“Energy storage has proven to be a highly successful way to reduce emissions for several categories of ships. If we speed up the adoption of green technology for vessels transporting goods, then we will really get results!” Tommy Sletten, Corvus Energy, noted.

“Container vessels are often ‘low cost’ vessels and there is a reluctance to invest in green technology without other initiatives in place.”

He further said that in order to achieve the global goal of 50% carbon emission reduction by 2050, regulations and governmental initiatives are needed. Initiatives such as funds for newbuilds, slot priority in harbors and reduced port fees for green vessels will help greatly, according to Sletten.