From local authority buildings and airports to apartment developments, student accommodation and commercial facilities, reliable backup power plays an important role in keeping essential systems operational.
At Lance Power, we design, manufacture, install and commission generator solutions for a wide range of applications, including standard standby generators and more bespoke integrated power systems.
We are also an authorised supplier to YESSS Electrical, combining Lance Power’s generator expertise with YESSS Electrical’s nationwide network to support customers across the UK.
But one of the first questions when specifying a generator is simple:
Do you need standby power or prime power?
The terms are often used when comparing generators, but they refer to two different operating requirements.
What is standby power?
A standby generator provides backup electricity when the normal mains supply fails.
During normal operation, the building continues to use its usual electrical supply. If an outage occurs, the generator starts and supplies power to the required electrical systems until the mains is restored.
In many installations, an Automatic Transfer Switch, or ATS, monitors the mains supply and automatically transfers the electrical load to the generator when required.
Standby generators are commonly specified for:
Local authority and council buildings
Airports and transport facilities
Residential developments
Student accommodation
Public sector buildings
Critical infrastructure
Apartment buildings
In an apartment building or student accommodation development, for example, standby power may be required for systems including emergency lighting, lifts, access controls, fire safety equipment and pumps. Apartment buildings with a certain regulation need by law to have an emergency generator.
For larger sites such as airports or council facilities, the generator may need to support much more extensive electrical infrastructure.
The principle is the same in every case:
Standby power provides backup electricity when the normal supply is unavailable.
What is prime power?
Prime power is different because the generator is used as the main source of electricity, rather than simply providing backup during a mains failure.
A prime-rated generator is designed to operate for extended periods while supplying a varying electrical load, in line with the operating conditions specified by the manufacturer.
Prime power is typically used where:
There is no reliable mains supply
Grid connection is unavailable or impractical
A site is temporary or remote
Generator power is required for extended periods
Electrical demand varies throughout operation
This can include construction sites, remote facilities, temporary infrastructure and certain industrial applications.
So, in simple terms:
Standby power = backup power when the mains fails.
Prime power = the generator is the primary source of power.
Why can the same generator have different ratings?
One area that often causes confusion is generator output.
A specification sheet may show one kVA figure for standby power and another for prime power, even though it is the same generating set.
The standby figure is often higher.
This is because generator ratings are based on different operating conditions, including expected running hours, load profile and how frequently the generator is required to operate.
It is therefore important not to select a generator based purely on the highest kVA figure shown on the datasheet.
The intended application needs to come first.
What should you consider when specifying a generator?
Choosing between standby and prime power is only one part of the process.
A generator also needs to be sized and specified around the electrical requirements of the site.
Important factors can include:
Total electrical load
Starting currents
Essential systems
Expected operating hours
Load variations
Fuel storage
Acoustic requirements
Available installation space
Ventilation and exhaust requirements
Automatic changeover
Remote monitoring
Future power demand
The priorities can vary significantly depending on the application.
For apartment buildings and student accommodation, noise, space and integration with existing building services may be key considerations.
For airports, local authority sites and larger commercial facilities, resilience, automatic operation and system integration may be more critical.
More than just the generator
A reliable standby power solution often involves much more than supplying the generator itself.
Depending on the project, the complete system may also include:
ATS panels
Fuel systems
Control systems
Remote monitoring
Acoustic enclosures
Electrical installation
Planned maintenance
Testing and commissioning
This is particularly important on larger or more complex projects, where each element of the system needs to work together correctly when mains power is lost.
Lance Power supports customers from initial specification through to manufacture, installation, commissioning and ongoing maintenance.
Through our relationship with YESSS Electrical, we have also completed a wide range of projects together, from standard generator installations through to bespoke standby power systems for commercial developments, infrastructure and industrial facilities.
Choosing the right generator for your application
The correct generator is not simply the one with the highest output.
It needs to match the way the site operates, the systems that must remain powered and the length of time the generator may be required to run.
For a residential development, that could mean protecting essential building services during a power outage.
For an airport or local authority facility, it could mean maintaining critical operations and infrastructure.
For an off-grid or temporary site, prime power may be the more appropriate solution.
Understanding the application first allows the generator to be sized and specified correctly.
Need help choosing the right generator for your application?
Speak to the Lance Power team.
📞 +44 333 222 4368✉️ info@lance-power.com