What is a Diesel Generator? Working, Benefits & Limitations


In Brief: What is a Diesel Generator

A diesel generator is a machine that produces electrical energy with the help of an alternator and a diesel engine by combusting diesel. Benefits of diesel generators are they are cost-effective, readily available, versatile, and fuel-efficient, can handle heavy loads, needs less maintenance, have an efficient cooling system, last long, and are safe.

A generator is a device that combusts fuels, and the energy obtained is used to produce electrical power.

They are great backup devices when you are experiencing a power outage or need extra power to use specific tools.

A diesel generator produces electricity by converting the energy obtained from the combustion of diesel.

In this article, we will let you know the working mechanism of a diesel generator, followed by its pros and cons, and help you decide if you need a diesel generator for your home.

How Diesel Generator Works

An alternator and an inbuilt diesel engine are essential for the working of the diesel generator.

The engine rotates the generator with the help of the mechanical energy produced by the combustion of the diesel.

The alternator uses this energy and generates electric power based on the principle of electromagnetic induction.

When the diesel fuel is injected into the generator after introducing compressed air, it produces the heat to ignite the diesel and starts the generator.

The fuel system supplies the diesel to the engine, which can be in-built or in a separate tank. The voltage regulator levels the voltage and amperage of the alternating current generated.

The electric current generated is directed through copper wires to external power machines, devices, or entire electrical systems.

The exhaust gases released due to the combustion of diesel fuel is vented out through the exhaust system.

Diesel generators have high power output and hence preferred mostly for industrial, medical, and construction applications.

Benefits of Diesel generator

Diesel generators have many advantages over other conventional fuel generators, and in this section, we will let you know some key benefits of a diesel generator.


One of the key points to look at fuel generators is the fuel price itself. Diesel generators are less expensive when compared to other conventional generators as diesel is cheaper than fuels like gasoline.

The fuel prices might vary according to the fluctuations in the market.

Further, diesel generators need less maintenance, are quite efficient, and have fewer parts to replace regularly than other generators. All of these contribute to the low operating and maintenance cost of the diesel units.

Fuel is Easily available

Diesel is readily available throughout the USA at many gas stations, hardware stores.

You can also store diesel in a tank or containers up to a certain period making it readily available even if you don’t want to go outside to buy some.

It is also easy to get diesel during calamities and emergencies as it is a prevalent and significant fuel used in industries, agriculture, and military applications.

Versatile in nature

One of the most significant advantages of diesel generators is, they are versatile as they find their applications in various industries and households alike.

They can be used as a temporary backup solution or to supply power full time because of their ability to handle heavy loads and provide continuous power.

They can also run various tools and high-end machinery, depending on the model. They can be even used to supply energy in the absence of power grids.

Mostly, diesel generators are often used as a backup power supply for offices, hospitals, and industries.


Diesel is known to have a higher thermal efficiency than gasoline or other fuels. On average, diesel generators consume less fuel around 50% lower than the petrol units.

Because of this, it is possible to get a massive amount of energy and have a longer running time when compared to other generator units operating at the same capacity.

This makes diesel a highly fuel-efficient generator unit than gas-based units. Further, due to the fuel-efficiency, diesel generators are good at supplying continuous power.

Keep in mind that the more amount of diesel you provide to the system, the more power it produces.

The fuel efficiency of diesel generators also reduces operating costs and saves you energy and money in the long run.

Handle heavy loads

Diesel generators can handle heavy loads effectively for an extended period.

This makes them ideal to power up areas that don’t have a power grid connection for more extended periods.

They can take the load of an entire power grid, and in the case of a temporary network shut down, they can be used for an Uninterrupted Power Supply (UPS) till the grid is back to function.

The ability to handle heavy loads allows diesel generators to find its use in powering up complicated medical equipment at hospitals, airports, and ships, large households, and construction work.

Efficient cooling

Diesel generators have an inbuilt cooling component that handles the heat built up during the combustion of diesel effectively.

Because of this, diesel engines can achieve peak effectiveness very fast without requiring extra coolants, water pumps, radiators, or temperature gauges.

Low maintenance

A diesel generator needs less maintenance than any other fuel generators. They also don’t need spark plugs or wires for support, therefore, decreasing maintenance costs.

A water-cooled diesel can operate up to 12,000 to 30,000 hours at a speed of 1800 rotations per minute before any major maintenance is necessary.

While water-cooled gas unit running at the same speed can only operate for 6000-10,000 hours before it requires maintenance.

At most, all you have to do is change the oil in the diesel generator regularly to ensure a longer life span of the system.


Diesel generators have a longer life span than gasoline ones as they are sturdy and reliable and can settle well even in harsh conditions if maintained correctly.

On average, the diesel generator lasts three years more than other alternatives.

Safe fuel

When compared to fuels like gasoline and propane, diesel is less inflammable, less explosive, and hence diesel generators are relatively more harmless.

Limitations of a Diesel generator

There are also certain disadvantages associated with diesel generators, and here we are listing a few of them.

Higher initial and repair costs

Diesel generators are generally more expensive to buy than other generator units.

Repairs and parts replacements for a diesel generator could be a costly business compared to other fuel generators.

Complex installation

The installation of diesel units takes more time than conventional fuel generators sometimes.

Also, it costs around the quarter of the whole amount of money needed to buy the entire system.
Because of this, the startup cost of the system goes up.

Higher Noise Levels

One of the significant downfalls of diesel generators is they produce lots of noise when they are functioning.

This is a considerable inconvenience for you and your neighbor, especially if you are running the generator unit at night, you can kiss goodbye to your good night’s sleep.

If you are running the unit in a working environment, you might need a soundproof enclosure. Some diesel generators have an inbuilt sound blocking canopy; however, such units could be expensive.

Weight and size

Diesel generators are bulky and weigh more than their counterpart petrol generators.

They have heavy components and system parts. Because of this, servicing for a diesel generator is a hassle.

Many times weight and size depending on the model.

Less Portable (as generally heavy)

Owing to their heavy parts and bulky size, diesel generators are one of the less preferred portable generator types.

If you use heavy containers or tanks to store diesel, the overall portability of the unit is limited further.

Less environmentally friendly

Diesel is considered a pollutant in many areas as it is not a clean source of energy. The emissions produced by combusting diesel are not the most environmentally friendly.

When to buy a Diesel generator

If your area doesn’t have a power grid supply or if your home needs a plentiful backup supply for heavy loads, you need to consider buying a diesel generator.

Diesel generators are versatile and find it’s applications in many sectors.

If you are looking for a cheaper fuel to reduce the operating costs of your generator, it’s time for you to get a diesel generator. Diesel is also readily available as it is one of the standard fuels used in many industries.

Further, diesel engines have a beneficial cooling system; they often have a longer life span and safer than gasoline counterparts.

If you don’t want to waste your time and energy doing maintenance chores for your generator, a diesel generator is for you as it requires less or no maintenance.

Finally, diesel offers a great contingency backup option in the case of emergencies as diesel can be stored up to many months without any degradation


There are many things to consider when you decide to get a generator power back up for your home.

With lower running and maintenance costs, high fuel and output efficiency, and less maintenance, diesel generators could be the best fit for your home’s backup needs.

But at the same time, they also have some disadvantages that should be looked into before buying one.

Here, we have tried our best to explain the diesel generator’s functioning along with its pros and cons.

We hope this will help you in your final decision if you are considering getting a diesel generator for your home.

About Michelle

Michelle has been fascinated with machines and tools since her childhood. She contributes with articles on how things work, repairing, and troubleshooting. She holds an engineering degree and pursuing her passion for travel.