Importance of Proper Fuel Tank Sizing
Ensuring uninterrupted continuous operation
A power generator must ensure continuous operation, especially in applications that require reliability such as data centers, mining, agribusiness, energy companies, large-scale construction, or telecommunications systems. Properly sizing the fuel tank is crucial to avoid unplanned shutdowns for refueling, which may lead to operational failures and losses.

Factors to Consider When Sizing the Fuel Tank

Generator-specific fuel consumption
Each generator has a specific fuel consumption rate, typically expressed in liters per hour (L/h) at a certain load percentage. This data is provided by the manufacturer and is the starting point for tank sizing.
Example: If a generator consumes 10 L/h at 75% load, it will require 240 liters in 24 hours.

Desired operation time (autonomy)
Define how long the generator should run without refueling. In critical applications, the minimum recommended autonomy is 8 hours.

Safety margin
It’s recommended to add a 10% to 20% safety margin to the calculated volume to account for:

Load fluctuations

Environmental conditions (e.g., extreme temperatures)

Minor losses during refueling

Type of fuel used
The type of fuel affects storage. Liquid fuels like diesel require special care for long-term storage to prevent degradation or contamination.

Fuel Tank Volume Calculation

Basic formula:
Tank Volume (L) = Hourly Consumption (L/h) × Desired Operation Hours × (1 + Safety Margin)

Detailed example:

Consumption: 8 L/h

Continuous operation: 48 hours

Safety margin: 15% (1.15)

Required volume = 8 × 48 × 1.15 = 441.6 liters

Recommended tank capacity: ~450 liters

Adjustments for real operation
In cases of load variation during the day, calculate consumption based on the weighted average load.

Types of Fuel Tanks for Generators

Integrated tanks
Built into the generator’s base frame. Suitable for short/medium-duration operations or mobile generators.

External tanks
Additional tanks installed to increase autonomy. Can be aboveground or underground, usually with automatic fuel transfer systems.
Examples:

Infrastructure projects use 2,000–10,000 L tanks for large generators.

Specific sectors use redundant systems with large-capacity and automated refueling.

Regulations and Legal Requirements for Fuel Storage

Environmental regulations
Fuel storage is subject to strict environmental standards to prevent soil and water contamination. In Brazil, CONAMA and ABNT (e.g., NBR 13786) regulate installations.

Leak containment system
External tanks must be installed within containment basins capable of holding at least 110% of tank volume.

Inspections and periodic maintenance
Tanks must be periodically inspected for structural integrity, leak detection, and fuel quality.

Strategies to Increase Autonomy Without Oversizing the Tank

Optimize generator load
Eliminate unnecessary loads and operate the generator within its optimal efficiency range to reduce fuel consumption.

Use parallel generator systems
Deploying multiple generators allows shutdown of units during low demand, cutting total fuel use.

Alternative fuels or additives
In certain cases, fuel additives or blends can enhance engine performance and extend operational autonomy.

Proper Sizing Ensures Efficiency and Safety
Correctly sizing the generator’s fuel tank is essential to ensure operational continuity, reduce logistical costs, and comply with regulations. An undersized tank causes critical failures, while an oversized one increases costs unnecessarily.

By considering actual consumption, desired operation time, safety margins, and fuel characteristics, you can strike the ideal balance. Furthermore, compliance with environmental and safety standards ensures not only technical success but also sustainability and legal conformity.

At Geraforte, we offer customized tanks for power generators in various sizes and specifications. Contact us—our team of engineers and specialists is ready to help!