Generator size calculator

Power rentals for oil and gas, utilities, mining, or an event need quick fixing. The site should not experience downtime.  

Choosing the correct generator size is key here. Why? A smaller generator size runs the risk of failure, while a bigger size means wasted cost and fuel.  

Calculating the generator size is the quickest way to make the right choice. This way your site never loses power, and you have a reliable estimate to begin with.  

While an online calculator is a good starting point, it’s always better to talk to the experts at Aggreko, as with our knowledge we’ll get the most efficient setup.

Generator sizing is a complex task, and recommendations may vary based on the project.  

Here are key steps to follow when renting generators for your next big project:    

• Estimate your total power needs  

  Start by estimating the total power requirements of the site. You should account for both the starting wattage and the running wattage.  

• Convert load to generator size  

  Your equipment’s power is rated in kilowatts(kW), while generators are rated in kilovolt-amps(kVA). Convert kW to kVA using this formula:  

  kVA = kW/Power factor  

  Most generators operate at a power factor of 0.8, but it can vary depending on the onsite requirements. Get in touch with our power team to get actual power estimates.  

• Allow a safety margin  

  In areas with demanding environments, keeping a buffer between the generator size and the total power need is important. This buffer improves efficiency and reduces carbon buildup.  

Every site is different, so before finalising the generator size, always check for: 

1. Ambient temperature and altitude: Harsh environments reduce generator performance, so you may need to size up  
2. Space and accessibility: Ensure there is enough room for delivery, ventilation, or refueling  
3. Load behavior & power continuity: For fluctuating loads, we suggest using multiple small generators or hybrid battery systems instead of one generator unit  
4. Fuel type and availability: Diesel is common, but alternate fuels such as biodiesel and HVO are increasingly becoming popular  
5. Noise restrictions: Silent generators may be required as per the project requirements  
6. Operating hours and maintenance: Longer operating hours may require larger fuel tanks or more frequent servicing.  

These smaller checks ensure your generator runs efficiently from day one.   

Proper generator sizing is not just about matching numbers. It’s about understanding the full picture of your power needs and site conditions.  

Rightsizing ensures that your generator system is tailored precisely to your operational demands, maximising performance and reliability.  

Here are the critical elements to consider:  

1. Evaluating operating parameters: Understand how your site consumes power. For example, a construction site may have peak loads in the morning and lighter loads later. Rightsizing accounts for these patterns.  
2. Understanding project-specific requirements: Each project is different. An event venue in Doha or a data centre in Dubai will have unique load profiles and environmental challenges. Aggreko customises sizing to your site’s specifics.  
3. Using specialised tools and expertise: This includes remote monitoring software that provides real-time fuel usage data, optimises energy consumption, and reduces running costs.  

Choosing the right generator size delivers far more than just power, it drives efficiency, cost savings, and sustainability. Here’s why rightsizing is a smart investment for your project:  

1. Lower operating costs: Reduced fuel consumption and fewer maintenance cycles.  
2. Maximum efficiency: Generators operate within their optimal load range.  
3. Reduced energy consumption: Power supply matches demand, eliminating inefficiencies.  
4. Minimal environmental impact: Efficient fuel use leads to fewer emissions.