Gasoline Basics
from old Kid's Gasoline
Did You Know?
Gasoline changes with the seasons.
The main difference between winter- and summer-grade gasoline is their vapor pressure. Gasoline vapor pressure is important for an automobile engine to work properly. During cold winter months, vapor pressure must be high enough for the engine to start easily.
Gasoline evaporates more easily in warm weather, releasing more volatile organic compounds that contribute to health problems and the formation of ground-level ozone and smog. In order to cut down on pollution, the Environmental Protection Agency requires petroleum refiners to reduce the vapor pressure of gasoline used during the summer months.
Gasoline — A Petroleum Product
Gasoline is a nonrenewable fuel made from petroleum. Refineries in the United States produce about 19 gallons of gasoline from every 42-gallon barrel of crude oil that is refined. The rest of the barrel gets turned into other petroleum products like diesel fuel, heating oil, jet fuel, and propane.
Gasoline Is Refined From Crude Oil
Most gasoline is made from crude oil, formed from the remains of plants and animals (diatoms) that lived hundreds of millions of years ago. These remains were covered with layers of sediment over time. With extreme pressure and high temperatures over millions of years, these remains became the mix of liquid hydrocarbons (an organic chemical compound of hydrogen and carbon) that we call crude oil. Refineries break down these hydrocarbons into different products. These "refined products" include gasoline, diesel fuel, heating oil, jet fuel, liquefied petroleum gases, residual fuel oil, and many other products.
Uses of Gasoline
A Gallon a Day Per Person
Americans use about 380 million gallons of gasoline every day. With about 304 million people in the United States, that equals more than a gallon of gasoline every day for each man, woman, and child. The United States does not produce enough crude oil to make all of the gasoline used by U.S. motorists. Only about 34% of the crude oil used by U.S. refineries is produced in the United States. The rest is imported from other countries.
Gasoline Is the Number One Transportation Fuel Used in the United States
Gasoline is one of the major fuels consumed in the United States and the main product refined from crude oil. Consumption in 2008 was about 138 billion gallons, an average of about 380 million gallons per day. Gasoline accounts for about 62% of all the energy used for transportation, 46% of all petroleum consumption, and 17% of total U.S. energy consumption. About 44 barrels of gasoline are produced in U.S. refineries from every 100 barrels of oil refined to make numerous petroleum products.
Source: Stock photography (copyrighted)
Most gasoline is used in cars and light trucks. It also fuels boats, recreational vehicles, and farm, construction, and landscaping equipment.
While gasoline is produced year-round, extra volumes are made and imported to meet higher demand in the summer. Gasoline is delivered from oil refineries mainly through pipelines to an extensive distribution chain serving about 162,000 retail gasoline stations in the United States.
249 Million Vehicles on the Road
Today, gasoline is the fuel used by most passenger vehicles in the United States. There are about 249 million vehicles that use gasoline, and they each travel over 12,000 miles per year. There are about 162,000 fueling stations that provide convenient refueling for consumers. Nearly two-thirds of fuel used for transportation is in the form of gasoline.
Each gasoline station usually sells three grades of gasoline:
- Regular
- Midgrade
- Premium
Octane Ratings and Seasonal Differences
These grades have different "octane ratings" that reflect anti-knock properties. In addition to these different grades of fuel, gasoline sold by a single company may differ depending on location or season. Some areas of the country are required to use special gasolines that reduce the amount of pollution coming from cars.
History of Gasoline
from Kid's Gasoline, April 2008
The First Oil Well Was Dug Just Before the Civil War
Edwin Drake dug the first oil well in 1859 and distilled the petroleum to produce kerosene for lighting. Drake had no use for the gasoline or 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 were popping up everywhere.
Source: G.H. Eldridge, NOAA (Public Domain)
Higher Octane and Lead Levels
By the 1950s, cars were becoming bigger and faster. Octane levels increased and so did lead levels; lead was added to gasoline to improve engine performance.
Leaded Gasoline Was Taken Off the U.S. Market
Unleaded gasoline was introduced in the 1970s, when the health problems from lead became apparent. In the United States, leaded gasoline was completely phased out in the 1980s, but it is still being used in some parts of the world.
Gasoline & the Environment
from Kid's Gasoline, April 2008
Gasoline Use Contributes to Air and Water Pollution
Burning gasoline produces carbon dioxide, a major greenhouse gas. Scientists know with virtual certainty that increasing greenhouse gas concentrations tend to warm the planet.1
Gasoline is a highly flammable and toxic liquid. The vapors given off when it evaporates and the substances produced when it is burned (carbon monoxide, nitrogen oxides, particulate matter, and unburned hydrocarbons) contribute to air pollution.
Did You Know?
Burning a gallon of gasoline produces about 19 pounds of carbon dioxide.
In 2007, total U.S. carbon dioxide emissions from gasoline combustion were about 1,180 million metric tons, about 20% of total U.S. carbon dioxide emissions.
Laws Such as the Clean Air Act Reduce Environmental Impact
Americans use about 380 million gallons of gasoline every day. Reducing pollution from gasoline has been a focus of environmental laws in the United States.
The Clean Air Act is the major law aimed at reducing air pollution. The Clean Air Act (first passed in 1970) and its amendments have aimed to reduce pollution from driving by requiring both cleaner cars and cleaner fuels (gasoline and diesel). The Environmental Protection Agency (EPA) put these goals into action by requiring the following:
- Removal of leaded gasoline — Leaded gasoline was officially banned in 1996 as a result of the Clean Air Act. Lead from gasoline proved to be a public health concern. The move away from leaded gasoline originally 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; the presence of lead in the fuel damages the catalytic converter.
- Reformulated gasoline — The Clean Air Act Amendments of 1990 required the sale of a cleaner reformulated gasoline beginning in 1995 to reduce air pollution in certain metropolitan areas with the worst ground-level ozone pollution.
- Low sulfur gasoline — Beginning in 2006, refiners are now required to supply gasoline containing much less sulfur levels than in the past, reducing the sulfur levels in gasoline by 90%. Cutting the sulfur in gasoline reduces emissions from both old and new vehicles alike. In addition, the Clean Air Act requires all new cars to have new pollution control devices, which cannot work properly with higher sulfur fuels.
- Reduced risk of gasoline leaks — Gasoline leaks happen at gas stations every day. As we fill up our 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 where we can’t see them in pipelines or underground storage tanks. Beginning in 1990, all buried tanks are supposed to be replaced by tanks with a double lining as an additional safeguard for preventing leaks.
In some places where gasoline leaked from storage tanks, one of the gasoline ingredients called methyl tertiary butyl ether (MTBE) made its way into local water supplies. Since MTBE made water taste bad and many people were worried about drinking it, a number of States banned the use of MTBE in gasoline, and the refining industry voluntarily moved away from using it when blending reformulated gasoline.
1. U.S. Environmental Protection Agency, Climate Change State of Knowledge.