A power outage can last longer than expected, whether due to storms, technical malfunctions, or energy supply bottlenecks. Those who own a backup generator have a choice between different fuels. However, gasoline, diesel, and gas differ in performance, handling, and safety. This article clearly explains which engine is suitable for which application, the advantages and disadvantages of each fuel, and what you need to consider for storage.
Gasoline engine – light, quiet, and mobile
Gasoline generators are often used for mobile applications and smaller consumers. Their strengths and weaknesses:
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Advantages:
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Very quiet operation.
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Low weight; therefore easy to transport.
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Relatively low acquisition costs.
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Especially suitable for short-term outdoor applications.
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Disadvantages:
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Gasoline is highly flammable and must not be stored indoors; therefore, stationary indoor installations are excluded.
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The fuel has a limited shelf life and ages faster. Gasoline lasts for several years in an airtight metal canister under optimal conditions, but only 2-3 months in a plastic canister; with stabilizers, up to 3 years.
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Higher consumption compared to diesel.
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For mobile use in the garden, for camping, or as a short-term emergency supply, gasoline generators are a good solution. However, they should be operated outdoors and only cover current needs.
Diesel engine – robust and economical
Diesel generators are considered the classic choice for a durable and reliable emergency power supply.
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Advantages:
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Very reliable and durable.
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Can be operated with heating oil or biodiesel.
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Starts reliably even at very low temperatures.
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Lower fuel consumption and high economic efficiency.
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Stationary diesel generators can automatically take over within a few seconds if the grid fails.
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Disadvantages:
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Larger and heavier; installation and maintenance require specialized knowledge.
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Noise and vibration are higher; exhaust gases must be safely discharged outdoors.
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Acquisition costs are higher than for gasoline models.
- Diesel has a shorter shelf life than gasoline (max. 6 months), as biodiesel components can promote bacterial growth and sludge formation (diesel bug). By using HVO, the storage period can be significantly extended (5 years shelf life).
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Diesel generators are suitable for continuous operation, for households with higher power demands, or when an automatic start in case of power failure is desired. With adequate ventilation, they can be installed stationary.
Gas operation – clean, but often dependent on electricity
Gas-powered backup generators (natural gas or LPG) offer a clean alternative with lower emissions. However, there are a few things to consider:
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Advantages:
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Very quiet operation and little odor.
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Low pollutant emissions.
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Liquefied petroleum gas (LPG) can be stored in bottles or tanks and has a long shelf life under normal conditions.
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Disadvantages:
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Natural gas appliances are tied to the supply network. According to the official planning guide of the state of Schleswig-Holstein, the gas supply is secured with emergency power for measurement and control technology, but the operation of gas heaters, gas stoves, and gas boilers is not possible during a power outage without their own emergency power supply, as ignition and safety devices are electrically controlled. In the event of a prolonged blackout, it is therefore unclear how long the gas network will remain functional.
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LPG requires its own tanks or bottles, the supply of which may be uncertain in times of crisis.
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Gas generators are less common and more expensive to purchase.
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Gas-powered devices are particularly suitable for short-term use and low power requirements, provided sufficient gas supplies are available. However, in the event of prolonged power outages, the supply is not guaranteed.
Fuel storage
The safe storage of fuel is regulated by law. In Germany, according to the garage ordinance, a maximum of 200 liters of diesel and 20 liters of gasoline may be stored in tightly sealed, unbreakable containers in small garages up to 100 m². In larger garages, the storage of fuels outside of vehicles is not permitted. Additional regulations apply to heating oil, gas cylinders, or other fuels. Important:
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Store fuel only in designated, unbreakable containers.
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Storage areas must be well-ventilated and protected from sparks or open flames.
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Regularly check the condition of the containers; old fuel can damage equipment.
Conclusion – finding the right generator
The choice of the right fuel depends on your requirements:
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Gasoline: Light and inexpensive, ideal for mobile, short-term outdoor use.
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Diesel: Robust solution for stationary operation, economical in consumption, suitable for automatic emergency power systems.
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Gas: Clean alternative, but dependent on gas supply and less common.
Remember that gas heating and appliances will not work during a power outage without their own emergency power source for safety reasons. Store fuels according to regulations and have stationary systems installed by professionals.
We at SEV GmbH will be happy to advise you on the selection of the right emergency generator and help you find the optimal solution for your home or business. Contact us – we are here to support you with our experience.