Why Is It Important to Size Your Generator Hire Correctly?
Date: 26/06/26
There is much more to sizing your site generator hire than simply making sure it gives you enough power. Correct generator sizing can improve fuel efficiency, significantly cutting operating costs and reducing carbon emissions. It also protects your people and your equipment, and keeps your project on schedule by reducing downtime and power outages.
In this article, we’ll look at why it is important to size portable generator hire correctly, and what could go wrong if you choose the wrong-sized generator. Remember, the friendly team of technical experts at Think Hire is always on hand with advice to help you if you need it. Just give us a call, and we’ll be happy to help
The Risks of an Undersized Generator
If costs are important to you, then you may be tempted to go for a smaller generator than you really need. However, while this may be cheaper to hire in the short term, the resulting costs can be significant.
Site generator hire should be sized to cope with both total running load and peak starting loads, as many items of equipment demand much higher power during start-up. If you use an undersized generator, your power demand will inevitably exceed generator capacity, leading to overloads. This can cause a number of problems, including:
-
Overheating and fire risks
-
Mechanical stress and damage
-
Reduced generator lifespan
-
Dangerous power fluctuations
-
Tripped breakers and power outages
-
Damage to connected equipment
-
Increased fuel consumption and emissions
Disruptive power outages can seriously delay your project. This will incur high costs in paying an idle workforce, and it could result in penalties for late delivery.
The risks of an oversized generator
With the risks of undersizing your portable generator hire in mind, you may think that the best approach is to allow plenty of extra margin on top of your power needs. However, oversized generators can also be unnecessarily costly, and it’s often the case that less is more.
Oversized generators often run at less than 50% of capacity. This can cause a serious problem called wet stacking, where unburnt fuel and carbon from exhaust gases cause damage to generator motors. Running a larger generator than you need can also result in:
-
Wasted fuel through inefficient idling
-
Excess carbon emissions
-
Higher noise levels
-
Increased hiring and transport costs
What Are the Financial and Operational Benefits of Correct Generator Sizing?
Choosing a site generator hire that is too large or too small causes significant problems and additional costs. That’s why the team at Think Hire work with our clients to ensure that they get the right size generator for every project, both now and in the future as they grow.
Choosing the right sized site generator hire gives you:
-
Maximum Fuel Efficiency – generators work most efficiently at 70-80% of capacity, so it’s important that they are not running at significantly more or less than this level. Finding the right balance can save thousands of pounds in fuel costs.
-
Extended Lifespan – correctly sized portable generator hire will result in lower maintenance costs, fewer breakdowns and outages, and prolonged life of the generator unit.
-
More dependable power – choosing the right sized portable generator hire means your team can count on consistent, uninterrupted power whenever they need it.
How a BESS Can Find the Balance
One of the easiest ways to find the balance between too much generator capacity and too little is to include a battery energy storage system in your energy grid.
With a BESS, you can reduce the size of your site generators without compromising on the energy available. BESS stores energy for use during peak demand, reducing the need for higher capacity generators. BESS helps to even out demand through peak shaving and load shifting, so you can run a smaller generator for less time and achieve the same results.
Find the Right Generator Hire With Think Hire – the Site Energy Experts
Think Hire has been powering sites across the UK for years with efficient, effective site generator hire. For expert advice on the best size for your generator, get in touch today. From solar and diesel generators, to hybrid generators and battery energy storage systems, Think Hire has the power solution you need
Frequently Asked Questions About Generator Sizing
Running a generator at 100% capacity will cause it to overheat, leading to premature wear and tear along with the risk of fire and catastrophic failure. For optimal performance and longevity, generators should run at no more than 70 to 80% of maximum load.
Yes. If a generator is too big, it will run well below capacity, often at 30% or less. This prevents it from reaching the ideal operating temperature and leads to ‘wet stacking’, which can damage the engine. Oversized generators are also more expensive to hire, cost more to run and produce excessive emissions.
Ideally, you should have your generator requirements calculated by a qualified electrician. You can also get help from your portable generator hire company. The expert team at Think Hire are always happy to help you find the optimum generator size for your site.
Yes. Because a BESS stores energy for use during peak demands, such as equipment start-up, you may not require as large a generator. Battery energy storage systems can smooth out the peaks and troughs in demand, so a smaller generator is needed to maintain supplies.
Download the Think Hire Brochure
We have over 60 years combined experience in the design, manufacture, hire and sale of innovative products, with an environmentally considerate power supply.