What Cars Use to Run: Fuels, Electricity, and the Systems That Turn Energy into Motion

Cars run on energy sources—primarily gasoline, diesel, or electricity—converted into motion by engines or electric motors; some also use hydrogen or alternative fuels. Beyond energy, they rely on supporting fluids like motor oil and coolant, plus air for combustion in traditional engines. This article explains the main types of energy cars use, how those systems work, what consumables are involved, and how the landscape is changing in 2025.

The Main Energy Sources Cars Use

Most passenger cars rely on a small set of energy types. The items below outline the fuels and power sources in use today, along with where you’ll most commonly find them and what they imply for performance, emissions, and fueling/charging.

• Gasoline (petrol): The most common fuel for passenger cars worldwide. Used in spark-ignition internal combustion engines (ICE). Fast refueling, wide availability, higher tailpipe emissions than electric.
• Diesel: Common in light trucks and some cars, especially in Europe and for towing/hauling. Used in compression-ignition engines. Offers high torque and efficiency, but produces NOx and particulates; many regions are tightening rules and consumer demand has softened.
• Electricity (battery-electric vehicles, BEVs): Stored in rechargeable batteries and delivered to electric motors. Zero tailpipe emissions, quiet operation, lower routine maintenance; charging speed and infrastructure availability vary by region.
• Hybrid systems (HEV and PHEV): Combine gasoline (or occasionally diesel) with electric motors and batteries. HEVs self-charge via the engine and regenerative braking; PHEVs also plug in for electric-only driving on shorter trips.
• Hydrogen (fuel cell electric vehicles, FCEVs): Hydrogen reacts with oxygen in a fuel cell to generate electricity for an electric motor. Fast refueling and long range, but passenger-car hydrogen infrastructure remains sparse outside select regions.
• Alternative and renewable fuels: Ethanol blends (e.g., E10, E85), biodiesel and renewable diesel, compressed natural gas (CNG), liquefied petroleum gas/propane (LPG), and emerging synthetic “e-fuels.” Adoption varies by market and infrastructure.

While gasoline still dominates the global vehicle fleet, battery-electric and plug-in hybrids are rapidly growing; according to the International Energy Agency, EVs (BEVs and PHEVs) accounted for about 14% of global new car sales in 2023 and were on track to reach roughly the mid-to-high teens percentage in 2024, with continued growth into 2025.

How Energy Becomes Motion

Internal Combustion Engines (Gasoline and Diesel)

Combustion engines mix fuel with air (oxygen) and ignite it—by spark in gasoline engines or by compression in diesel engines. The resulting expanding gases push pistons connected to a crankshaft, producing rotational power that drives the wheels through a transmission. Exhaust systems, catalytic converters, diesel particulate filters, and selective catalytic reduction (DEF/AdBlue) manage emissions.

Battery-Electric Drivetrains

In BEVs, large traction batteries supply electricity to inverters and electric motors. Motors create torque directly, often enabling strong, immediate acceleration. Regenerative braking recovers energy when slowing. Thermal management systems heat and cool the battery for performance and longevity. Charging occurs via home or public chargers, from standard AC to high-power DC fast charging.

Hybrid Systems

Hybrids pair a combustion engine with one or more electric motors and a battery. Full hybrids can propel the car on electricity at low loads and use the engine for higher demand; plug-in hybrids add a larger battery that you can charge, enabling electric-only trips before the engine assists. Control software optimizes when to use electric vs. engine power for efficiency.

Fuel Cell Electric Vehicles

FCEVs generate electricity onboard by combining stored hydrogen with oxygen from the air in a fuel cell, emitting only water vapor from the tailpipe. A traction battery buffers power and captures regenerative braking energy, similar to BEVs. The main constraints are hydrogen production, distribution, and refueling station networks.

Other Things Cars “Use” to Keep Running

Energy is essential, but reliable operation also depends on other consumables and components. The items below highlight common needs that vary by powertrain.

• Air (oxygen): Required for combustion in gasoline and diesel engines; engines draw filtered air through an intake system.
• Motor oil and lubricants: Lubricate and protect moving parts in ICEs; EVs still use gear oil and greases for driveline components but no engine oil changes.
• Coolant/thermal fluids: Manage temperatures in engines, batteries, motors, and power electronics to maintain efficiency and durability.
• Transmission and brake fluids: Hydraulics for braking; automatic transmissions or dedicated reduction gears require proper lubrication.
• Fuel-system fluids: Diesel exhaust fluid (DEF/AdBlue) for many modern diesels to reduce NOx emissions.
• Electric power (12-volt/low-voltage systems): Regardless of powertrain, cars rely on a low-voltage system for computers, lighting, and accessories; in EVs and hybrids, DC-DC converters maintain this system from the traction battery.
• Tires and filters: Tires, engine air filters (ICE/hybrids), cabin air filters, and in some cases fuel filters, require periodic replacement.

Keeping these systems in good condition—through regular maintenance and software updates where applicable—ensures the energy you use is converted into reliable, safe motion.

Choosing the Right Energy Source

The best choice depends on your driving patterns, local infrastructure, climate, and policy. Consider the factors below when deciding among gasoline, diesel, hybrid, battery-electric, hydrogen, or alternative fuels.

• Total cost and availability: Fuel/charging prices, incentives, resale value, and access to home or workplace charging.
• Range and refueling/charging time: Long trips favor fast refueling or high-power charging access; daily commuting can suit overnight charging.
• Emissions and regulations: Local emissions rules, low-emission zones, and tax policy affect operating freedom and costs.
• Maintenance and reliability: EVs have fewer routine service items; ICEs are well-understood with widespread service networks.
• Climate and performance: Cold or hot weather affects battery range and engine efficiency; thermal management matters.
• Use case: Towing/hauling, urban driving, or fleet duty cycles may favor different powertrains.

Matching your typical driving profile and local infrastructure to a powertrain usually yields the best mix of cost, convenience, and environmental impact.

Trends in 2025

As of 2025, gasoline remains dominant in the global fleet, but electrification is accelerating. Battery-electric and plug-in hybrid sales continue to grow, supported by maturing charging networks and improving battery chemistries such as LFP for cost and durability. Hydrogen fuel cells remain niche for passenger cars, with greater momentum in heavy-duty applications and specific regional corridors. Biofuels and synthetic e-fuels are supplementing existing ICE fleets, primarily via blends. Policy measures and automaker commitments are steering the market toward lower emissions, while consumers weigh charging access, energy prices, and vehicle availability.

Summary

Cars run on energy—most commonly gasoline or diesel, with rapidly growing use of electricity and limited but important roles for hydrogen and alternative fuels. Engines and motors convert that energy into motion, supported by fluids, filters, and electronics that keep systems operating safely and efficiently. The right choice for any driver depends on cost, infrastructure, range needs, and environmental goals, all against a backdrop of fast-evolving technology and policy in 2025.

What kind of fuel do cars run on?

gasoline
Currently, the majority of motor vehicles worldwide are propelled by internal combustion engines powered by petroleum-based fossil fuels such as gasoline, diesel or autogas.

Do cars run on gas or oil?

Our vehicles consume both fuel and oil; oil enters the combustion chamber and burns along with the fuel. Both your vehicle’s engine design and your driving style determine just how much oil it consumes. As your vehicle is running, the engine oil consistently circulates around the combustion chamber.

What does a car use to run?

A gasoline car typically uses a spark-ignited internal combustion engine, rather than the compression-ignited systems used in diesel vehicles. In a spark-ignited system, the fuel is injected into the combustion chamber and combined with air. The air/fuel mixture is ignited by a spark from the spark plug.

What does a car require to run?

Without this spark, the three things an engine needs to run – air, fuel, and ignition – couldn’t combine to create the combustion process. The battery, alternator, and starter make up the three main components of the electrical system.