Stricter emissions regulations on top of cyclically high bunker prices and downturns in the shipping market have pushed the industry to adopt new measures to improve energy efficiency and ultimately reduce emissions.
As bunker fuel comprises a sizeable part of a shipping company’s operating costs, many companies are making unprecedented efforts to optimise ship energy efficiency.
The global maritime industry is crucial to international trade. It transports more than 90 per cent of the world’s goods by volume and employs a million seafarers. One widely accepted method of improving ship energy efficiency is developing accurate models that predict ship fuel consumption rates under different scenarios.
By identifying operational improvement through accurate assessment, cost savings and profitability can be achieved, while environmental impacts can be mitigated by lowering carbon emissions and air pollutants such as sulphur and nitrogen oxides.
New carbon intensity measures now require shipowners to measure their energy efficiency and initiate the collection of data to report on their annual carbon intensity indicator and rating.
Ships running on low-carbon or alternative fuels will receive higher ratings than ships running on fossil fuels. There are also several other improvements that can be implemented to raise a rating.
Research literature has identified solutions that aim to improve ship energy efficiency as either technical oroperational. Technical solutions include upgrading propellers, optimising vessel size, and designing the hull shape to reduce vessel resistance; using lightweight materials to lower vessel weight; selecting efficient power systems and machinery; switching fuel type; using scrubbers; recovering waste heat; and using solar, wind, and shore power.
Operational measures adopted by the shipping industry include improving on-time arrival consistency using route optimisation tools, reducing routing decision errors and excessive vessel motions to minimise ship and cargo damage, increasing crew comfort, reducing the ship’s structural maintenance, and routing optimisation considering emission control areas.
GOOD BUNKER MANAGEMENT AN EFFECTIVE WAY TO BOOST SHIP EFFICIENCY
It has been claimed that technical measures currently available are struggling to steer the shipping industry toward an energy-efficient and low-carbon direction because their application requires engineering innovation and also carries a hefty price tag.
In contrast, operational measures are much less expensive, do not require initial investment, and when well designed, they can achieve promising savings. However, a study published in Logistics and Transportation Review pointed out that applying effective and efficient operational solutions was not trivial, since various factors could influence the actual fuel consumption of a ship, making it difficult to capture the relationship between the influencing factors and the fuel consumption rate.
The researchers said: “Ship design (main dimensions, propulsion system, propeller design, hull/steel structure and cargo arrangement), vessel operational performance (sailing speed, draft, trim, displacement, hull performance, and dry docking), and environmental conditions (wind, wave, and current conditions, water and air temperature, and water depth) all influence ship fuel consumption and therefore energy efficiency.”
BALANCING ACT OF BUNKERING COSTS
A study published last year investigated the impact of uncertain waiting times and fuel prices on the selection of bunker fuels tops for ships engaged in tramp shipping. Tramp shipping refers to sea cargo transport based on demand orders, rather than fixed schedules and predetermined routes typical of liner shipping.
Given their focus on maintaining schedule reliability, liner ships usually undertake bunkering during regular port calls, avoiding deviations specifically for bunkering.
Bunker management can be defined as three interrelated components – selecting a bunkering port, deciding on thebunker volume to order, and selecting the vessel’s speed.
The researchers explained that for a tramp vessel under a voyage contract, choosing where to bunker was a complex problem, since the decision needed to balance the trade-off between the local fuel price, deviation from the shortest route, and the time spent in each potential bunkering port.
They said: “The assessment of waiting times is relevant, as a shipowner might take on bunkers in a relatively faster port at the expense of paying a higher fuel price.“Thus, the bunkering management decision could help to avoid cheap but inefficient ports that would subsequently cause the vessel to speed up to pick up the cargo within the contracted window.
“In other words, the cost of the additional fuel consumption could outweigh the apparent savings of buying fuel in a cheap but inefficient port (where large deviations, long waiting times and/or slow pumping rates are observed).”
Fuel price and its variation from port to port are typically the primary factors in choosing a bunkering location. However, this analysis modelled waiting times and found that low-cost ports may be less favourable if they were significantly less efficient.
Despite competitive pricing, low-cost ports can incur losses from extended waiting time when adopting a risk-averse approach.
The researchers said: “In our case study, the observed empirical waiting times didn’t deter the initial decision to head to the bunkering port with longer waiting times.“A closer look at the data suggests that there isn’t a premium associated with faster service – this suggests that reduced waiting times, although favourable, isn’t something customers are willing to pay a premium for.”
