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Environmental Science Ch. 11 Section 3 to the end of the chapter

Key Concepts:

Terms in this set (29)

In contrast to petroleum, natural gas contains only a few different hydrocarbons: methane and smaller amounts of ethane, propane, and butane. Propane and butane are separated from the natural gas, stored in pressurized tanks as a liquid called liquefied petroleum gas, and used primarily as fuel for heating and cooking in rural areas. Methane is used to heat residential and commercial buildings, to generate electricity in power plants, and for a variety of purposes in the organic chemistry industry.

Natural gas as a fuel for trucks, buses, and automobiles offers significant environmental advantages over gasoline or diesel.

The main disadvantage of natural gas is that deposits are often located far from where the energy is used. Because it is a gas and is less dense than a liquid, natural gas costs four times more to transport through pipelines than crude oil. To transport natural gas over long distances, it is first compressed to form liquefied natural gas (LNG), then carried on specially constructed refrigerated ships

Natural gas is more plentiful than oil. Experts estimate that readily recoverable reserves of natural gas, if converted into a liquid fuel, would be equivalent to between 500 billion and 770 billion barrels of crude oil, enough to keep production rising for at least 10 years after conventional supplies of petroleum have begun to decline. However, if the global use of natural gas continues to increase as it has in recent years, then its supply will not last as long as current projections predict.

Large amounts of natural gas have recently been discovered in shale formations around the United States, and it is likely that similar deposits are waiting to be discovered elsewhere in the world. Removing shale gas can be more expensive and environmentally disruptive than the resources we have been accessing, but shale gas extraction is taking place in an increasing number of places around the country
As with coal, the burning of oil and natural gas produces CO2. Every gallon of gasoline you burn in your automobile releases an estimated 9 kg (20 lb) of CO2 into the atmosphere. As CO2 accumulates in the atmosphere, it insulates the planet, preventing heat from radiating back into space. The global climate is warming more rapidly now than it did during any of the warming periods following the ice ages, and the environmental impact of rapid global climate change could cause substantial human suffering in the future.

Another negative environmental impact of burning oil is acid deposition. Although burning oil does not produce appreciable amounts of sulfur oxides, it does produce nitrogen oxides, mainly through gasoline combustion in automobiles, which contributes approximately half the nitrogen oxides released into the atmosphere. Nitrogen oxides contribute to acid deposition and, along with unburned gasoline vapors, the formation of photochemical smog.

The burning of natural gas, on the other hand, does not pollute the atmosphere as much as the burning of oil. Natural gas is a relatively clean, efficient source of energy that contains almost no sulfur, a contributor to acid deposition. In addition, natural gas produces far less CO2, fewer hydrocarbons, and almost no particulate matter, as compared to oil and coal.

One of the concerns in oil and natural gas production is the environmental damage that may occur during their transport, often over long distances by pipelines or ocean tankers