When comparing Prime-rated with Standby-rated generators the wording may sound and look confusing as most contractors and end users do not know that there are different types of generators on the market. Different brands as well yes, but different types when comparing a generator that should only be running for an hour at a time vs a diesel Gen-set that was built to run continuously.
The difference could be in the ratio between the engine and the alternator, the size of the radiator and cooling equipment, silencers and exhausts, etc. Prime rated Generators are more expensive and have shorter warranties. With Solar systems being installed on sites where the diesel Generator is expected to also charge the batteries during emergencies, contractors may find themselves in a predicament with incorrectly sized generators that were never built to run for longer periods of time.
The 3-biggest mistakes in commercial Solar PV BESS applications
- Incorrectly Sized Generator
- Incorrectly Specified Generator
- Mains Supply too small
Size
Specification
Cheaper is not better when considering Diesel Generators and the cheapest quote will often buy an under-rated diesel Generator with the incorrect controller. For Diesel Generators to be integrated with Solar PV systems, you would want to have a controller that is intelligent enough to handle some of the requirements for Grid-Tied inverters that typically push excess power back into the electrical network. Although the warranty conditions for Stand-by generators may look more appealing, a Stand-by generator is typically only rated to run for about an hour in a 24-hour cycle.
Mains Supply
The “Mains Supply” would typically be the size of the “Mains isolator” as supplied by the municipality. It is not uncommon for commercial users to operate at the limit or the mains supply and start considering solar systems as a means to increase their connected capacity. Adding a solar PV system with a battery bank often means that the batteries will have to be charged during periods where there is no sunshine; this new battery bank could easily push the load demand over the available capacity resulting in mains circuit breakers tripping.
Increase profitability and reduce risk
We trust the information in this section has proven to be useful and that it can be used to assist you in system design by highlighting potential areas of risk. Our latest Commercial Solar PV Design course reduces risk even further by looking at other potential areas in an installation that could be detrimental to the success and viability of commercial and industrial solar PV solutions.
