Do You Know The Differences Between Diesel And Petrol Generators?

August 26, 2019 11:13 am

Do you know the difference between a diesel and a petrol generator? If you’re looking to buy a generator, it pays to know the difference. 

As with cars, everyone seems to have an opinion on which one is better, but the truth is, the things that separate them, are getting fewer and fewer. But there are still some ways they differ. Here’s how:

The Environmental Differences

Diesel engines haven’t always had the best reputation. In the past, they were thought of as noisy, dirty, and polluting things that cough out black smoke. However, things have moved on dramatically in recent years. Modern, UK made diesel engines are much quieter and cleaner. And, when it comes to thinking about the planet, diesel generators are much more fuel-efficient than they ever have been.

Petrol engines have lower compression, meaning they need to work harder to produce the same amount of power. The result is that more fuel is required to run them. So, while petrol generators produce less CO2, because of fuel efficiency, diesel engines will produce less CO2 in the long run.

How Long Do The Engines Last?

UK made diesel engines last longer than petrol engines which is why, wherever you go in the world, you will see diesel power trucks, construction vehicles, and industrial-sized generators. One reason for the longevity of diesel engines comes back to the fact that a diesel engine does not have to work as hard to produce the same amount of power as a petrol engine.

The knock-on effect of this is that diesel engine parts last longer as well. Plus, there are fewer parts to go wrong in the first place. Diesel is self-lubricating, so no problems with fuel delivery systems. Finally, diesel engines don’t need an ignition system, so nothing to go wrong or wear out there either.

The Drawbacks Of Diesel

If you feel like the arguments here are only going one way (extolling the virtues of diesel generators), hang on, as they do have their drawbacks too. One big difference between petrol and diesel generators are their cooling systems. Generators can be air-cooled or liquid-cooled and which one you choose depends much on what you are going to use it for.

If you’re looking for a portable generator to use during brief power outages or other short periods of time, then an air-cooled petrol generator is almost certainly the way to go. However, if you are looking for more of a workhorse generator that will stay in-situ, then a liquid-cooled generator is likely to be a better choice.

How Much Do The Generators Cost?

This is a tricky one to answer because when it comes to buying a generator, petrol generators are generally cheaper, which is why many people prefer them. In addition, diesel fuel is more expensive to buy than petrol, which is another major drawback for some people when looking at the differences between the two. However, you may not be surprised to hear that it’s not as simple as that.

You also need to consider all the ways diesel engines trump petrol engines: Diesel engines last longer, they have fewer moving parts, they are easier to maintain, and they are more fuel-efficient

So, even though the initial cost of a petrol generator may be cheaper and buying fuel will be gentler on the wallet, in the long run, you may well end up paying more for parts, maintenance and overall fuel costs. It really boils down to how much you are going to use the generator.

How Safe Are the Two Types of Generator?

Fortunately, this is a much easier question to answer. Without a doubt, diesel is a much safer fuel. Not only is it less volatile, but it is much safer to store. If you are planning to have it constantly running, having hundreds of liters of petrol lying around the place is a recipe for disaster. Plus, there is a difference in the way the two engines work.

Petrol engines require an ignition system to get them started, which means they need a spark. And, of course, this means any kind of spark is dangerous around petrol. Diesel fuel does not have the same dangers. All in all, therefore, diesel generators are a far safer option.


In summary, when looking at the differences between petrol and diesel generators, diesel takes the prize. However, remember that what you want the generator to do also plays a part. If you’re looking for something you can move around for light usage, petrol is probably the better choice. For more prolonged and more constant use, you should consider a diesel generator. 

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