What Does a Generator Run On?

by Anna

Generators are invaluable assets in modern society, providing backup power during outages and serving as essential components in various industries. Yet, understanding what fuels these machines can be surprisingly complex. Generators are designed to run on different types of fuel, each with its advantages and limitations. In this article, we delve into the diverse range of fuels that power generators, exploring their characteristics, applications, and environmental impacts.



Gasoline is one of the most common fuels used in portable generators due to its widespread availability and ease of use. It is a liquid petroleum product derived from crude oil through refining processes. Gasoline-powered generators typically feature internal combustion engines that convert the chemical energy in gasoline into mechanical energy, which is then converted into electrical energy through an alternator.


The advantages of gasoline as a generator fuel include its high energy density, quick ignition, and relatively low cost compared to other fuels. Gasoline generators are also highly portable and versatile, making them suitable for various applications, from powering outdoor events to providing emergency backup power for homes and small businesses.

However, gasoline has some drawbacks as well. Its volatility poses safety risks, particularly during storage and transportation. Gasoline also emits pollutants such as carbon monoxide (CO) and nitrogen oxides (NOx) when burned, contributing to air pollution and potential health hazards. Additionally, gasoline generators may require frequent refueling, especially during prolonged outages, which can be inconvenient and impractical in certain situations.


Diesel generators are widely used in both stationary and mobile applications, ranging from residential standby power systems to industrial facilities and construction sites. Diesel fuel is a petroleum distillate similar to gasoline but with a higher energy density and lower volatility. Diesel engines operate on the compression-ignition principle, where fuel is ignited by the heat generated from compressing air in the combustion chamber.

One of the key advantages of diesel generators is their fuel efficiency and longer runtime compared to gasoline generators. Diesel fuel is less volatile than gasoline, reducing the risk of accidents during storage and handling. Diesel engines also tend to be more durable and require less maintenance than gasoline engines, making diesel generators a popular choice for continuous operation in commercial and industrial settings.

Moreover, diesel fuel combustion produces fewer greenhouse gas emissions and particulate matter than gasoline, making diesel generators relatively cleaner and more environmentally friendly. However, diesel exhaust still contains pollutants such as nitrogen oxides and sulfur dioxide, albeit in lower concentrations compared to gasoline engines. Diesel generators also tend to be larger and heavier than gasoline generators, limiting their portability and requiring dedicated storage and installation space.

Natural Gas:

Natural gas is an increasingly popular fuel choice for stationary generators, particularly in urban areas with access to natural gas pipelines. Natural gas is a fossil fuel composed primarily of methane, with smaller amounts of other hydrocarbons and impurities. Natural gas generators utilize internal combustion engines similar to those used in gasoline and diesel generators but modified to burn gaseous fuels.

One of the main advantages of natural gas generators is the continuous and reliable fuel supply provided by natural gas pipelines, eliminating the need for onsite fuel storage and refueling. Natural gas is also cleaner burning than gasoline and diesel, emitting fewer pollutants such as carbon monoxide, nitrogen oxides, and particulate matter. Additionally, natural gas generators tend to be quieter and produce less vibration than diesel generators.

However, natural gas generators have some limitations. They may be more expensive to install initially due to the required infrastructure for gas supply, such as pipelines and regulators. Natural gas availability may also be limited in rural or remote areas without access to gas pipelines, restricting the feasibility of using natural gas generators in such locations. Furthermore, natural gas prices can be volatile, potentially impacting operating costs for natural gas generators over time.

Propane (LPG):

Propane, also known as liquefied petroleum gas (LPG), is a versatile fuel commonly used in residential, commercial, and industrial applications, including generators. Propane is a byproduct of natural gas processing and petroleum refining, consisting primarily of propane, butane, and other hydrocarbons. Propane generators operate similarly to natural gas generators but use propane as the fuel source instead of natural gas.

One of the key advantages of propane generators is their versatility and portability. Propane is stored in liquid form under pressure, allowing for convenient storage and transportation in portable tanks. Propane generators offer a reliable alternative for off-grid applications or locations without access to natural gas pipelines. Additionally, propane burns cleaner than gasoline and diesel, emitting fewer pollutants and greenhouse gases.

Propane generators also have a longer shelf life compared to gasoline, making them suitable for standby power applications where extended periods of storage may be necessary. However, propane generators may have higher upfront costs than gasoline generators due to the need for specialized fuel storage and delivery systems. Propane availability can also be limited in certain regions, particularly in remote areas far from distribution centers.


Biogas is a renewable energy source produced through the anaerobic digestion of organic materials such as agricultural waste, municipal solid waste, and wastewater. Biogas primarily consists of methane and carbon dioxide, with trace amounts of other gases and impurities. Biogas generators utilize internal combustion engines or fuel cells to convert the energy stored in biogas into electricity.

One of the main advantages of biogas generators is their environmental sustainability and renewable nature. Biogas production helps reduce greenhouse gas emissions by capturing methane, a potent greenhouse gas, and converting it into electricity. Biogas generators also provide a means of waste management by utilizing organic waste materials to generate energy, reducing the need for landfill disposal.

Moreover, biogas generators offer energy independence and resilience by diversifying the energy supply away from fossil fuels. They can be particularly beneficial in rural areas with abundant organic waste resources, such as agricultural operations and wastewater treatment plants. However, biogas production requires specific infrastructure for anaerobic digestion and gas capture, which may entail significant capital investment and operational challenges.


Hydrogen is a versatile energy carrier that can be produced through various methods, including electrolysis of water, steam reforming of natural gas, and biomass gasification. Hydrogen fuel cells are electrochemical devices that convert hydrogen and oxygen into electricity and water through a chemical reaction, with no combustion involved. Hydrogen generators utilize fuel cells to produce electricity from hydrogen fuel.

One of the key advantages of hydrogen generators is their high efficiency and zero-emission operation. Hydrogen fuel cells produce electricity with higher efficiency and lower emissions compared to internal combustion engines, making them a promising technology for clean and sustainable power generation. Hydrogen is also abundant and can be produced from renewable sources, such as solar and wind power, further enhancing its environmental benefits.

Hydrogen generators offer scalability and flexibility, with applications ranging from portable backup power systems to grid-scale energy storage and transportation. Hydrogen fuel cells can also operate silently and produce no harmful emissions, making them suitable for indoor use in residential and commercial settings. However, hydrogen infrastructure and storage technologies are still under development, posing challenges for widespread adoption and commercialization.

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Generators play a crucial role in ensuring reliable power supply for various applications, from emergency backup power to continuous operation in remote locations. The choice of fuel for generators depends on factors such as availability, cost, environmental impact, and specific application requirements. Gasoline, diesel, natural gas, propane, biogas, and hydrogen are among the most common fuels used in generators, each with its advantages and limitations.

While fossil fuels such as gasoline and diesel remain prevalent due to their energy density and infrastructure compatibility, renewable fuels like natural gas, propane, biogas, and hydrogen are gaining traction for their environmental sustainability and energy independence. As technology advances and renewable energy sources become more accessible, the future of generator fueling is likely to evolve towards cleaner, more efficient, and sustainable options, contributing to a more resilient and environmentally friendly power generation landscape.


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