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Oil (petroleum)


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Gasoline Basics

Gasoline—a petroleum product

Gasoline is a fuel made from crude oil and other petroleum liquids. Gasoline is mainly used as an engine fuel in vehicles. Refineries in the United States produce about 19 gallons of gasoline from every 42-gallon barrel of crude oil that is refined. Refineries and companies that produce the finished motor gasoline sold in retail gasoline fueling stations may add various liquids so that the gasoline burns cleaner and meets air pollution control standards and requirements. Most of the motor gasoline now sold in the United States also contains about 10% fuel ethanol by volume. This is required by a federal law intended to reduce the amount of oil that the United States imports from other countries.

A gasoline pump showing different grades of gasoline
Many cars on the road

Source: Stock photography (copyrighted)

There are three main grades of gasoline sold at retail gasoline refueling stations:

  • Regular
  • Midgrade
  • Premium

Some companies have different names for these grades of gasoline, like unleaded, super, or super premium, but they all indicate the octane rating, which reflects the anti-knock properties of gasoline. Higher ratings result in higher prices.

Before 1996, lead was added to gasoline as a lubricant to reduce wear on engine valves. Leaded gasoline was banned for sale in the United States on December 31, 1995. Manufacturers recommend the grade of gasoline for use in each model of a vehicle. However, most gasoline-fueled vehicles will operate on regular gasoline, which is usually the least expensive grade.

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Uses of Gasoline

Americans use more than a gallon of gasoline per person each day

Americans used about 375 million gallons of gasoline per day in 2014. With about 319 million people in the United States in 2014, that calculates to more than a gallon of gasoline every day for each person.

Gasoline is the primary transportation fuel used in the United States

Gasoline is one of the major fuels consumed in the United States, and it is the main product refined from crude oil. About 10% of the volume of finished motor gasoline now consumed in the United States is ethanol. In 2014, gasoline (including fuel ethanol) accounted for about 65% of all the energy used for transportation, 47% of all petroleum consumption, and 17% of total U.S. energy consumption. About 45 barrels of gasoline are produced in U.S. refineries from every 100 barrels of oil refined to make petroleum products.

Most gasoline is used in cars and light trucks
Hundreds of cars in a traffic jam

Source: Stock photography (copyrighted)

Gasoline is used in most cars, sport utility vehicles, and light trucks. Gasline is also used in boats; recreational vehicles; small aircraft; and farm, construction, and landscaping equipment.

Most of the gasoline consumed in the United States is used in light-duty vehicles

Light-duty vehicles (cars, sport utility vehicles, and small trucks) in the United States account for about 90% of all gasoline consumed. The total amount of gasoline these vehicles use is determined by the number of vehicles, how many miles they travel, and the fuel economy of the vehicles. The U.S. Energy Information Administration (EIA) estimates1 that there were about 227 million light-duty vehicles in use in 2014, and the average number of miles traveled per vehicle was about 11,750 miles. The average fuel economy of all light-duty vehicles was about 22.25 miles per gallon.

1. Estimates from the Annual Energy Outlook 2015, reference case tables 2, 37, 40, 41, and 42

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History of Gasoline

Gasoline was initially discarded

Edwin Drake dug the first oil well in Pennsylvania in 1859 and distilled the oil to produce kerosene for lighting. Although other petroleum products, including gasoline, were also produced in the distillation process, Drake had no use for the gasoline and other products, so he discarded them. It wasn't until 1892 with the invention of the automobile that gasoline was recognized as a valuable fuel. By 1920, there were 9 million vehicles on the road powered by gasoline, and service stations selling gasoline were opening around the country. Gasoline is the fuel used by most of the light-duty vehicles in the United States.

The Ford Model T ran on gasoline and ethanol
Photograph of a Ford Model T

Source: Stock photography (copyrighted)

Gasoline octane and lead levels increased over time

By the 1950s, cars were becoming bigger and faster. Gasoline octane increased, and lead was added to improve engine performance.

Leaded gasoline was eventually taken off the U.S. market

Unleaded gasoline was introduced in the 1970s when health problems from lead became apparent. In the United States, leaded gasoline for use in on-road vehicles was completely phased out as of January 1, 1996. Most other countries have also stopped the use of leaded gasoline in vehicles.

Ethanol is added to gasoline

In 2005, the U.S. Congress enacted a Renewable Fuel Standard (RFS) that set minimum requirements for the use of renewable fuels, including ethanol, in motor fuels. In 2007, the RFS renewable fuel use targets were set to rise steadily to a level of 36 billion gallons by 2022. In 2014, about 13 billion gallons of ethanol were added to the gasoline consumed in the United States. In most areas of the country, the retail gasoline that is now sold is about 10% ethanol by volume.

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Gasoline & the Environment

Gasoline use contributes to air pollution

Gasoline is a toxic and highly flammable liquid. The vapors given off when gasoline evaporates and the substances produced when it is burned (carbon monoxide, nitrogen oxides, particulate matter, and unburned hydrocarbons) contribute to air pollution. Burning gasoline also produces carbon dioxide, a greenhouse gas linked to global climate change.1

Did you know?

Burning a gallon of gasoline (that does not contain ethanol) produces about 19.6 pounds of carbon dioxide.

In 2014, total U.S. carbon dioxide emissions from gasoline combustion were about 1,077 million metric tons, approximately 20% of total U.S. energy-related carbon dioxide emissions.

Laws like the Clean Air Act reduce environmental impacts

Americans used about 375 million gallons of gasoline per day in 2014. Most gasoline is used in cars, light trucks, and motorcycles, but it is also used in small aircraft, boats, and water craft, and in landscaping and construction equipment. Reducing pollution from these sources has been a focus of environmental laws in the United States.

The Clean Air Act is a law that seeks to reduce air pollution in the United States. The Clean Air Act (first passed in 1970) and its amendments have aimed to reduce pollution from gasoline use by requiring the use of less polluting engines and fuels2, among other items. To meet its goals, the U.S. Environmental Protection Agency (EPA) implemented several changes following the passage of the act:

  • Required emissions control devices and cleaner burning engines—Emissions control devices on passenger vehicles were required beginning in 1976. In the 1990s, the EPA established emissions standards for other types of vehicles and for engines used in gasoline-burning off road equipment.
  • Removed leaded gasoline—Lead in gasoline proved to be a public health concern. The move away from leaded gasoline began in 1976 when catalytic converters were installed in new vehicles to reduce the emission of toxic air pollutants. Vehicles equipped with a catalytic converter cannot operate on leaded gasoline because the presence of lead in the fuel damages the catalytic converter. Leaded gasoline was completely phased out of the U.S. fuel system by 1986.
  • Required the use of reformulated gasoline—Beginning in 1995, the Clean Air Act Amendments of 1990 required the use of cleaner burning reformulated gasoline to reduce air pollution in metropolitan areas that had significant ground-level ozone pollution.
  • Required the supply of low-sulfur gasoline—Since 2006, refiners have been required to supply gasoline with 90% less sulfur content than they made in 2004. More reductions in gasoline sulfur content are planned to begin in 2017. Gasoline with lower sulfur content reduces emissions from old and new vehicles, and it is necessary for advanced vehicle emission control devices to work properly.
  • Reduced risk of gasoline leaks—Gasoline leaks happen at gas stations every day. As people fill up their gas tanks, gasoline drips from the nozzle onto the ground and vapors leak from the open gas tank into the air. Gasoline leaks can also happen in pipelines or in underground storage tanks4 where they can't be seen. Beginning in 1990, all underground storage tanks had to be replaced by tanks with double lining. The double lining provides an additional safeguard for preventing leaks.

Methyl tertiary butyl ether (MTBE), one of the chemicals added to gasoline to help it burn cleaner, is toxic, and a number of states started banning the use of MTBE in gasoline in the late 1990s. By 2007, the U.S. refining industry had voluntarily stopped using MTBE when making reformulated gasoline for sale in the United States. MTBE was replaced with ethanol, which is not toxic.

1. U.S. Environmental Protection Agency, Climate Change Science.

2. U.S. Environmental Protection Agency, Transportation: Mobile Sources.

3. U.S. Environmental Protection Agency, Nonroad Engines, Equipment, and Vehicles.

4. U.S. Environmental Protection Agency, Underground Storage Tanks.