Diesel generators v. Petrol generators: which is the best?

Diesel generators v. Petrol generators: which is the best?
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When it comes to engines, there’s no greater grudge match then diesel generator versus petrol generator.

But this battle isn’t restricted to the road – it’s a battle that extends to, worksites, homes, businesses and farms across Australia. It’s a battle of the generators.

Here at My Generator, we know for a fact that diesel generator are some of the most cost-effective and fuel-efficient units you can buy. But petrol generators have come of age and are taking on diesel generators at their own game. So who will reign supreme? We’ll be the judge of that…

Diesel Generator Pros

For decades, people only knew diesel as a dirty, smelly truck fuel. But it’s done a complete 180 to give petrol a run for its money – literally. Because one of the biggest advantages of diesel engines is their fuel efficiency. This comes down to the diesel motor’s higher compression. So a like for like comparison of diesel generator and petrol generator will put the diesel ahead.

With diesel you also get a lower cost of ownership. That’s why so many industries rely on diesel fuel to run their business, whether it’s for generators, bulldozers, excavators or tractors.  Diesel engines, and therefore diesel generators, last longer, cost less to run and take longer to depreciate in value. Why do they last longer? Because diesel engines don’t have to work as hard as petrol engines to get the same power output. This means the engine parts are under less stress. Also diesel fuel is self-lubricating which means the fuel delivery system should last longer than that of a petrol engine – perfect if the generator hasn’t been used for a while.

Diesel generator

Diesel Generators are often more efficient and require less maintenance than their petrol counterparts

Another thing that gives the diesel engine the upper hand is the lack of an ignition system. It simply doesn’t need one, which means one less thing to fail. What’s more, they can operate at loads between 60% to 100% for prolonged periods, which is an advantage over its petrol counterparts.

While you can find diesel generators powering smaller loads, such as domestic appliances for back up or DIY tasks, the advantages are best seen in more heavy industrial and mining applications. In fact, diesel generators are the backbone of the mining and construction industries.

Diesel generator

Diesel Generators come into their own for Mine Specific Applications

Diesel Generator Cons

Diesel engines emit more noxious gases and CO2 per litre of fuel than petrol-powered engines. However, the upside is that because diesel engines use less fuel, they can also emit less CO2 over time. It all depends for how long you are using your generator.  Cost is another factor. Traditionally, diesel has been more expensive than petrol – about 10% more in Australia. But the balance is certainly tipping.

Even though diesel generators last longer and are less likely to fail, they may be more expensive to fix when they do.

Petrol Generator Pros

Besides the cost of petrol being lower than diesel, there are a few pros for petrol. There is more choice of models for petrol generators. Like cars, this is because petrol generators have been around for longer. But that said, you’ll find a growing selection of diesel generators for a whole range of applications and budgets these days; including home/business backup, trade/construction applications, solar set up backup, events and much more.

While diesel generator are lauded for their fuel efficiency, petrol generators are now being build with all kinds of economy modes and features to bridge the gap.

 

Petrol Generator Cons

Petrol is much more volatile than diesel fuel. So if you’re carrying lots of fuel for your generator, diesel is a safer option. Also, because of the way diesel engines work, they are much safer than petrol engines. There’s no spark ignition, which means no risk of explosion and less maintenance than a petrol generator. At the same time, with petrol generators today, a whole variety of safety features and checks are incorporated to ensure this isn’t an issue anyway.

Another downfall of petrol generators is that they reach a higher temperature than their diesel counterparts. This leads to more wear and tear on the generator parts over time, meaning more frequent maintenance and repair, and ultimately, a shortly life span. Consequently, petrol generators are not usually run at high loads for extended periods.

The verdict

It’s a pretty close match…we say that if you are looking to use the generator for heavy commercial use, then diesel is probably the way to go. But if you are already operating other equipment with petrol, then a petrol generator can do the job also – when you consider leading Australian brands from the likes of Powerlite, Gentech, Dunlite or Crommelins they all have first rate options in both petrol and diesel. It really comes down to which model suits your application the best. Has this given you fuel for thought? Check out the full range of petrol and diesel generators at My Generator.

 

 

Sean Connolly

Sean Connolly

Managing Director at My Generator
Sean is the co-founder and Managing Director of My Generator (mygenerator.com.au)
Sean Connolly

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Comments

  • Markus October 16, 2015, 7:35 am

    I have a large industrial diesel generator at my farm and run a small petrol version at my house. I couldn’t agree with you more the only thing i would like to add is i find that the diesel generator creates a lot more noise then the petrol version.

    • My Generator Admin October 19, 2015, 12:10 am

      Thanks Markus. Yes, some Diesel sets can be louder than petrol counterparts although it obviously all depends on size of course; generally speaking, smaller gensets will be quieter than larger ones on a like for like basis. However, many diesel generators designed for backup purposes now have soundproof canopies with sound absorbing technology to “silence” the generator during operation. Thanks!

  • Ian Miscamble February 18, 2016, 12:33 pm

    My issue is a generator for Off Grid Solar back-up.
    The recommended generator is a Honda EU70is 4 stroke GX390 engine electronic fuel injection system max output 7000 w AC – rate output 5500w Recommeded as the quietest around from $6000 plus
    What can you recommend in either deisel or petrol that would be as good and pricing of same.
    The off grid solar is 5 kilowat capacity – house/shed – hobby farm usage

  • Abirami April 22, 2016, 12:38 pm

    An electric generator is a device that converts mechanical energy obtained from an external source into electrical energy as the output.It is important to understand that a generator does not actually ‘create’ electrical energy. Instead, it uses the mechanical energy supplied to it to force the movement of electric charges present in the wire of its windings through an external electric circuit. This flow of electric charges constitutes the output electric current supplied by the generator. This mechanism can be understood by considering the generator to be analogous to a water pump, which causes the flow of water but does not actually ‘create’ the water flowing through it.

  • Elight power August 8, 2016, 8:40 am

    Elight Power diesel commercial generators in Pakistan are for commercial uses which is beneficial to small scale as well as businesses operating on a large scale.

  • FPT Iveco Generators Dubai December 8, 2016, 10:45 am

    Its really an informative blog and can clear the differences between diesel and petrol generators for new buyers. We are leading suppliers of FPT iveco, Perkins UK and Lombardini generators in Dubai, UAE.
    https://www.adpower.ae/

  • Elight Power January 28, 2017, 6:52 am

    Elight Power Home Generators in Pakistan deal in Small Diesel Generators in Pakistan for commercial purposes. These diesel powered generators are perfect for commercial purposes such as schools, hospitals, super markets, banks etc.for more detail visit our website : http://elightpower.com/

  • Paul Hayes February 10, 2017, 5:32 am

    How about a discussion and or recommendation for a generator for grey nomads where – dare I say it – size matters.

  • Taf April 2, 2017, 2:54 am

    Hi there, I’m looking at a generator to power our home during blackouts such as the one we have just experienced following cyclone Debbie here in QLD Australia. We need to power a large fridge, water system, minimal lighting and TV/laptops so we can keep up with local news broadcasts. Would a diesel be suitable for sensitive electronic equipment?

    • L Adams April 3, 2017, 4:39 am

      Hi Taf, you’ve come to the right place. You have three main options in relation to types of generators (in both petrol or diesel) for your type of home backup power requirement. In terms of sizing, from what you’ve listed the only query would be the water system; water pumps can either be quite efficient or some can have significant start up (surge) requirements, so ideally you would know how much power your water pump system needs – often the best way is to get an electrician to take a meter reading on your home. Alternatively, for the main item in question, you can contact the pump manufacturer to get the maximum required power amount for your particular model. A large domestic fridge will typically require less than 2000 watts and your lights/TV/Laptops etc. will only draw a few hundred watts.
      So again, preferably you would know exactly how much power you need as you dont want to end up with a generator that is too small for your particular appliances. However, to help give you an idea, here is an outline of the different types you can choose from and some popular generator models for each option:

      Option 1: a portable inverter generator. These are petrol powered, lightweight, quiet, and suitable to run sensitive electronic equipment. You would just run a power board from the outlet of the generator and then plug your appliances in via extension chords. Popular models for your type of application are:
      Cromtech 2400w Inverter Generator
      Yamaha EF2800I Inverter Generator
      More options in this range here: http://www.mygenerator.com.au/inverter-generators.html

      Option 2: Have an electrician fit a manual transfer switch to your home; this will allow you to switch the power source to your home from mains power or to generator power. So, when a mains power blackout occurs, you can switch over to the generator source, plug the generator in and run either your whole home or certain parts of your home the electrician has isolated. Some people use generator models such as the ones listed above in Option 1, but more commonly, people opt for larger generator models with AVR (Automatic Voltage Regulation), such as:
      Yamaha Petrol 6kVA AVR EF7200E Generator
      Pramac Petrol Honda ES8000 7.2kVA Generator
      More options in this range here: http://www.mygenerator.com.au/avr-generators.html

      Option 3: An Auto-start generator that will automatically start up and restore power to your home when it detects a mains power failure. These units require a compatible accessory called an AMF (Automatic Mains Failure Panel) and an electrician to install to your main power switch board. Popular models include:
      Pramac Diesel 6kVA Auto Start Super Silenced Generator
      Pramac Diesel 8.8kVA Silenced Auto Start Generator
      More options in this range here (included gas powered gensets): http://www.mygenerator.com.au/auto-start-generators.html

      Overall, the more common approaches are Options 1 & 2 as they are cheaper and more straightforward. Option 3 has the benefit of automatically reinstating power to your home when a blackout occurs (even when you are not at home), but you’ll pay a bit more for this convenience. If you require further help, feel free to call us on 1300 400 122, thanks.

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