When choosing a diesel generator, many people have a similar question: should you go for Prime Power or Standby Power?
These terms may sound technical, but the difference is actually simple. Today, Voltgent will explain it in an easy-to-understand way so you can make the right choice with confidence.
Prime Power (PRP) VS Standby Power (ESP):
| Feature | Prime Power (PRP) | Standby Power (ESP) |
| Use Case | Used where there is no reliable utility power, such as remote construction sites, mines, or islands. Serves as the primary source of electricity. Long-term supply. | Used where utility power exists, but occasional outages may occur, such as factories, hospitals, or data centers. Serves as emergency backup. Backup only. |
| Run Time | Can run continuously for long hours, typically 8–12 hours or more per day. Long continuous operation. | Only runs during power outages as emergency backup, typically operating less than 200–500 hours per year. Occasional operation; <500 hours/year. |
| Load Capacity | Can sustain rated power long-term. The “main workhorse” – primarily relied on for everyday power needs. | Suitable only for short-term rated power |
Cost | Higher investment; higher fuel and maintenance requirements | Lower cost; simpler maintenan |
International Standard Reference (ISO 8528)
ISO 8528 defines global generator power ratings to ensure consistency and clarity. The main types are:
| Power Rating | Type Description |
| Emergency Standby Power (ESP) | Max power during outages or test conditions, ≤200 hours/year, 24h average ≤70% of ESP rating |
| Prime Rated Power (PRP) | Max continuous power under variable load, unlimited hours/year, 24h average ≤70% of PRP rating |
Selection Tips:
Picking the correct power rating isn’t just about matching size to power output. It's about matching the diesel generator to your actual usage profile, including:
1- Load factor: What is the average power demand?
2- Peak load: What’s the maximum power needed?
3- Run time: How many hours per year will the generator run?
4- Connection type: Will it run with or without the utility grid?
Voltgent Commitment
Whether you need a Prime Power generator or a Standby Power generator, we can provide the right solution for you. Our team will evaluate your specific needs and help you choose the most economical and reliable option.
Contact us today to get the power solution that best fits your requirements!
Email: info@voltgent.com
