Diesel vs. Petrol Generators

Which type is best for continuous or backup use?

Diesel generators and petrol generators are the most common on the market with both types having benefits and drawbacks in terms of performance, cost, efficiency and portability.

As well as working out which is better for either a continuous supply or as backup use, you will also need to work out what equipment it needs to power, to decide which to choose. 

When deciding which type of generator is better suited for either continuous use or as back-up supply, you will need to think about your own usage. A diesel generator that is used as the main power source for an extended period is called a prime generator. When a generator is used as a backup supply, for example during a power outage, this is referred to as a standby generator and used as backup power.

Diesel generators

In general, a diesel generator is a better option in terms of fuel efficiency, larger load handing and for lasting longer than its petrol counterpart. For applications where a more extensive power supply is needed, a diesel option is your preferred power set.

What are petrol generators used for?

Petrol generators tend to be used for small projects and applications and can be used to power projects for construction sites, agricultural machinery, domestic use and light industrial situations.

What are diesel generators used for?

Diesel generators are used to provide electricity in many different situations including when utility power is unavailable, or when backup power is needed. For example, diesel generators can be used to provide power for construction sites, agricultural operations and industrial and commercial situations.

What other fuel types can a generator run on?

Generators can run on a surprising range of fuel types, including diesel oil, biodiesel and even recycled vegetable oil. Although, most generators will require modification before they can run on pure alternative fuel sources. Today, where biofuel is used in generators, it tends to be mixed with diesel at a ratio of about 80% diesel to 20% biofuel.

Why is fuel efficiency important?

Since fuel is the main cost driver in generator ownership, fuel cost and fuel efficiency is a key issue. A generator which is not fuel-efficient will end up costing more money in the long run.

Efficiency is affected by factors such as the type of engine, the load on the generator (how much power it needs to produce) and the operating conditions. It is measured in terms of fuel consumption per hour of operation. The lower the fuel consumption, the more efficient the generator is.

In general diesel generators are more fuel efficient than petrol.

Petrol Generator

Why are noise levels important when deciding on your generator type?

One of the main disadvantages of diesel generators is that they are noisy. Noise levels are measured in dBA (decibels) and depend on the size of the generator and the load on the generator. A larger generator or a generator with a higher load will produce more noise.

How to reduce noise from a generator?

Noise can be limited by housing the generator in an acoustic enclosure or acoustic canopy. These are specially designed housings built from materials which absorb much of the sound. Petrol generators are typically quieter than diesel generators.

Which type of generator causes more vibration?

Diesel generators tend to produce more vibration than petrol generators. This can be a problem if the generator is not mounted on a solid foundation. Vibration can be reduced by using vibration-damping materials, but this adds to the initial expense.

How do you store diesel fuel correctly?

Diesel fuel must be stored in a cool, dry place. It can degrade if it is exposed to sunlight, water or high temperatures, so it must be stored in a dark, airtight container, preferably a dedicated diesel fuel tank where the fuel can be kept free from contaminants. If the fuel degrades, it’s possible to remove some of the contaminants by filtration – a process known as fuel polishing.

Are there any storage requirements for petrol-fuelled generators?

Petrol generators do not have the same storage requirements as a diesel-fuelled generator, so they may be a better choice if you do not have a suitable place to store diesel fuel. Biofuels in fact have a much longer shelf life than standard diesel – they can often be stored for up to 10 years without degrading compared with diesel which may last one year.

Are petrol generators cheaper to run than diesel generators?

Diesel generators are usually more expensive to operate, due to the higher cost of diesel fuel. However, diesel generators are more fuel-efficient than petrol generators, so they will use less fuel over time. Also, because diesel generators have fewer moving parts which can be subject to wear and tear, they can require less maintenance.

How much space does a petrol generator require?

Petrol generators are typically smaller than diesel generators, so they take up less space. This can be important if you are tight on space or if you need to move the generator around frequently.

What is the average lifespan of a diesel generator?

Diesel engines can last for tens of thousands of hours with proper maintenance, while petrol engines typically need to be replaced after a few thousand hours of use. Because diesel generators are more fuel efficient, their lifespan can often be significantly longer than petrol generators because they simply have to do less work to generate the same amount of energy.

Should I buy a diesel or petrol generator?

The decision of whether to buy a diesel or petrol generator depends on your specific project requirements. If you need a generator for backup power, a diesel generator will be more reliable and have lower maintenance costs. If you need a portable generator for smaller applications such as camping or construction, a petrol generator will be less expensive and easier to transport.

Rehlko Here to Help

At Rehlko, we believe your diesel generator is at the heart of your operations. As a global manufacturer and distributor of a variety of critical power generators and equipment, Rehlko are well-equipped to help you with all your generator requirements.

To keep your diesel generator running in full working order, Rehlko also provide a range of diesel generator maintenance contracts to suit all businesses and all budgets. All of our maintenance projects are undertaken by teams of experts, including Engineers, Project Managers, Consultants and Logistics Coordinators, all of whom are directly employed by us.

To find out more about the services we provide, speak to one of our experienced team members today and see how we can help you and your organisation.