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Diesel generators and petrol generators are two of the most common types on the market. They both have benefits and drawbacks, and it can be difficult to know which one is better for your needs. In this blog post, we will compare diesel generators and petrol generators in terms of performance, cost, efficiency, and portability. We will also discuss the pros and cons of each type of generator so that you can make an informed decision about which one is best for you.


Petrol engines were invented by Nikolaus Otto in the late 1800s. Petrol engines convert energy from petrol fuel into electrical energy. They are internal combustion engines, which means they have several chambers in which fuel is ignited. The combustion of the fuel within the cylinder creates an expansion of the gases, which forces the piston to move. In petrol engines, spark plugs are used to ignite the fuel-air mixture in the cylinders.

The movement of the pistons turns a crankshaft, to which the pistons are connected. Whilst the pistons move in an up-down direction, the crankshaft rotates horizontally. The other end of the crankshaft rotates within an alternator – a device which converts the rotational energy of the energy into electrical power by using electromagnetic induction.

Petrol generators tend to be used for small projects and applications. For example, they are used to provide power for construction sites, agricultural, domestic and light industrial situations.


Diesel engines are much like petrol engines in their basic workings – they also use multiple cylinders in which pistons move, and which are attached to a crankshaft which rotates within an alternator, converting fuel energy into electrical energy. But there are some key differences.

Like a petrol engine, a diesel engine is an internal combustion engine. But instead of using a spark plug to ignite the fuel-air mixture, diesel engines use compression to heat the air within the cylinder until it ignites. Diesel engines were invented by Rudolf Diesel in the late 1800s, so “Diesel” describes the type of engine, not the type of fuel.

Diesel fuel is a type of petroleum derived from crude oil. Diesel generators are available in a wide range of sizes, from small portable units to large stationary units that can power an entire factory. They are used to provide electricity in many different situations, such as when utility power is unavailable, or when backup power is needed. They are also used to provide power for construction sites, agricultural operations, and industrial and commercial situations.

When a diesel generator is used as the main power source for an extended period of time, it’s known as a prime power source. Standby power is when a generator is used as backup power in case of an outage.

Generators can run on a surprising range of fuel types, including diesel oil, biodiesel, and 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.


Since fuel is the main cost-driver to keep the generator operational, 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 many 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.


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. 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.


Another issue with diesel generators is that they 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.


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. Petrol generators do not have these storage requirements, 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.


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.


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.


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.


The decision of whether to buy a diesel or petrol generator will be dependent on the 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.