The hidden cost: eliminating redundant generator usage in maritime fleets
Eliminating redundant generator usage: where profit, people, and planet meet
In the maritime industry, pressure to optimise vessel performance is increasing on all fronts. While much of the focus tends to fall on main engines and hull efficiency, auxiliary power systems, particularly generators, often represent an overlooked opportunity for meaningful savings.
Generators run continuously to support onboard systems, but when operated inefficiently, they can quietly drive up fuel consumption, emissions, and maintenance costs. At ZeroNorth, we believe that turning operational data into clear action is one of the most effective ways to improve vessel performance and support the industry’s transition toward greener global trade.
From periodic monitoring to operational insight
To improve, we must first understand the current state of our operations. For decades, the industry has relied on traditional methods like manual daily noon reports and periodic inspections to track performance. These processes have served as the foundation of maritime reporting, providing essential data that has helped fleets manage their journeys.
However, the maritime data landscape is maturing. While traditional reports offer a valuable daily snapshot, they are often less suited to capturing the high-frequency fluctuations of complex systems like auxiliary generators. ZeroNorth brings guidance and clarity to help our customers navigate this evolution, harnessing expertise, technology, and trusted data at scale to build upon these established practices.
Understanding generator inefficiency at sea
In the complex ecosystem of a modern vessel, generators serve as the lifeblood of onboard operations, powering everything from navigation systems to crew accommodations. Yet, these systems remain a primary source of untapped efficiency.
Common patterns of redundancy
Vessels typically operate multiple generator sets to ensure redundancy and safety. This practice can sometimes lead to what is known as "spinning reserve"—extra capacity that consumes fuel without providing proportional benefits. This often occurs in a few common scenarios:
- Overestimated power requirements: engineers may run more capacity than strictly necessary to ensure a safety buffer, which can lead to fuel waste.
- Improper load distribution: when multiple units run at low loads, each becomes less efficient, consuming more fuel per kilowatt-hour produced.
- Established routines: crews may follow traditional patterns of running specific units based on habit rather than real-time demand.
The measurable upside of optimisation
Addressing these patterns creates a cascade of benefits. Beyond direct fuel savings, reducing unnecessary running hours lowers maintenance requirements and lubricant consumption, extending the lifespan of your assets. For a typical vessel, optimising generator usage can reduce auxiliary fuel consumption by 2-5%. This is a meaningful step that supports your "profit, people, and planet" by lowering costs and emissions while improving the work environment for your crew.
Smarter generator management with SmartShip
ZeroNorth’s SmartShip platform is designed to make these efficiencies visible and actionable. Using industrial-grade IoT technology, SmartShip connects onboard systems across the fleet to provide high-resolution operational insight.
High-frequency data for high-impact decisions
The transition to high-frequency data collection represents a quantum leap in monitoring. Instead of a single daily data point, SMARTShip can process over **5,000 data points** from various onboard systems. This granularity reveals the complete operational profile of auxiliary systems, including:
- Load fluctuations during different operational modes.
- Start-up and shutdown efficiency.
- Real-time response to changing power demands.
This data, combined with weather overlays and regulatory information, allows users to harvest unique insights that boost performance. For example, SMARTShip can evaluate over 80 million combinations to calculate the most effective fuel consumption for a voyage.
Implementing a collaborative approach to management
Technology is a powerful tool, but true optimization is a collaborative effort. We believe in being inclusive and curious, focusing on the needs and perspectives of the people on the frontline.
Standardising for consistency
Well-designed standard operating procedures (SOPs) for generator management create consistency across fleets. These should be living documents, regularly updated based on performance data and crew feedback. The goal is to provide intuitive applications that allow crews to monitor and diagnose issues in real time, making the complex clear through easily digestible insights.
Training and engagement
Engineering crews are the key to unlocking efficiency. Effective training programs help teams understand the "why" behind data-driven decisions. When crews see how their actions impact fuel consumption and equipment longevity, they become active participants in the journey to make global trade green.
Preparing for regulatory requirements beyond 2026
As regulatory frameworks tighten, auxiliary systems are coming under increased scrutiny.
The expansion of the EU ETS
The EU Emissions Trading System (EU ETS) has reached full compliance in 2026, with 100% of verified emissions subject to carbon pricing. For the first time, the scope now includes methane and nitrous oxide in the emissions accounting framework. This shift significantly impacts the cost of inefficient auxiliary operations, particularly for vessels with high "methane slip" or those using traditional marine fuels.
Enhanced IMO DCS reporting
The IMO Data Collection System (DCS) has also evolved. From January 1, 2026, data must be collected with an enhanced level of granularity. This includes reporting fuel consumption by consumer type (e.g., auxiliary engines vs. main engines) and distinguishing between "under way" and "not under way" status.
New emission control areas (ECAs)
Stricter standards are now in effect in new regions. On March 1, 2026, the Canadian Arctic and the Norwegian Sea became designated Emission Control Areas (ECAs). Ships operating in these sensitive waters must now meet Tier III standards for diesel engines larger than 130 kW, placing a premium on efficient engine performance.
Vessels equipped with SMARTShip can precisely document their performance across these categories, ensuring accurate reporting and helping to maintain a strong Carbon Intensity Indicator (CII) rating.
Building a culture of continuous improvement
Optimal efficiency is an ongoing process, not a one-time task. For maritime operators looking to stay competitive, establishing systematic monitoring is a strategic priority.
Shared success and vision
We lead, but we also listen. By sharing successful optimization initiatives across the fleet, organisations reinforce the importance of these efforts. This collaborative mindset, combined with trusted data, transforms generator efficiency from a technical goal into a shared organisational value.
ZeroNorth is here to provide the guidance and clarity you need to navigate this transition. By leveraging data to drive decision-making, you can create a virtuous cycle where environmental stewardship and financial performance reinforce each other. The future belongs to those who can harness data to navigate the dual imperatives of profit and planet.
FAQs
1. What exactly is "redundant generator usage" in maritime operations?
Redundant generator usage occurs when a vessel operates more auxiliary engines than are strictly necessary to meet the current electrical load. Often referred to as "spinning reserve," this practice is traditionally used as a safety buffer. However, it often results in generators running at low loads where they are least efficient. By using data to accurately match power supply with actual demand, operators can maintain safety while significantly reducing unnecessary fuel consumption and emissions.
2. How does generator loading impact specific fuel oil consumption (sfoc)?
Every generator has an "optimal sweet spot," typically between 70% and 85% of its maximum rated capacity. When a generator operates within this range, it achieves its best SFOC, meaning it produces the most power for the least amount of fuel. When multiple generators are run at low loads (e.g., two units at 30% instead of one at 60%), the engine's internal efficiency drops, leading to higher fuel burn and increased carbon intensity per kilowatt-hour produced.
3. Why is high-frequency data better than noon reports for generator monitoring?
Noon reports provide a valuable daily snapshot, but they often miss the fluctuations in power demand that occur throughout a 24-hour period. High-frequency data, such as that captured by SMARTShip, monitors performance every few minutes. This granularity allows technical managers to see exactly when an extra generator was started and whether the electrical load justified it. It turns "educated guesswork" into "trusted data," allowing for more precise operational adjustments.
4. How do auxiliary engines affect a vessel’s cii rating and eu ets costs?
While the main engine is the primary driver of emissions, auxiliary engines contribute significantly to a vessel's total carbon profile, especially during port stays or slow steaming. Under the 2026 EU ETS requirements, every tonne of CO2, methane, and nitrous oxide emitted by generators is subject to carbon pricing. By optimising generator usage, you directly lower your total emissions, which helps maintain a favourable Carbon Intensity Indicator (CII) rating and reduces the financial burden of carbon allowances.
5. Does running fewer generators at higher loads increase maintenance costs?
This is a common concern, but data suggests the opposite. Running generators at very low loads (under-loading) can lead to "wet stacking" or carbon build-up, which actually increases maintenance frequency and the risk of engine damage. By operating fewer units at their optimal load, you reduce total running hours across your equipment and ensure the engines operate at temperatures that keep components clean, ultimately extending the time between overhauls.