NONRENEWABLE FOSSIL FUELS

I.

Petroleum or crude oil (oil as it comes out of the ground) is a thick liquid consisting of hundreds of combustible hydrocarbons (organic compounds made of hydrogen and carbon), along with small amounts of sulfur, oxygen, and nitrogen impurities. This fossil fuel was produced by the decomposition of buried dead organic matter from plants and animals that were subjected to high temperatures over millions of years.

Oil reserves are identified deposits from which oil can be extracted profitably at current prices with current technology. The 11 countries that make up OPEC have 67% of the word's crude oil reserves, which explains why OPEC is expected to have long-term control over world oil supplies and prices. OPEC was formed in 1960 so that developing countries with much of the world's known and projected oil supplies could get a higher price for this resource. Today its members are Algeria, Indonesia, Iran, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, United Arab Emirates, and Venezuela. Saudi Arabia with 26%, has by far the largest proportion of the world's crude oil reserves, followed by Iraq, Kuwait, and Iran, each with 9 ¾ 10%. Currently, Russia has 13%of the world's oil reserves, and the United States ¾ only 2.3%.

Identified global reserves of oil should last about 53 years at the current usage rate and 42 years if usage increases as projected by about 2% per year. Undiscovered oil that is thought to exist might add another 20 ¾ 40 years to global oil supplies, probably at higher prices. Thus, known and projected supplies of oil are projected to be 80% depleted within 42 ¾ 93 years, depending on the annual rate of use.

Using conventional oil as an energy resource has its advantages and disadvantages. The advantages include its ample supply for 42 ¾ 93 years, low cost (with huge subsides), high net energy yield, easy transportation within and between countries, low land use. But at the same time we need to find substitute within 50 years, then artificially low price encourages waste and discourages search for alternatives. It pollutes air and releases CO₂ when burned and pollutes water and coast when spilled.

Some analysts contend that rising oil prices (when oil consumption exceeds oil production) will stimulate exploration and lead to enough new reserves to meet future demand through the nest century or longer. Other analysts argue that such optimistic projections about future oil supplies ignore the consequences of the high (2 ¾ 5% per year) exponential growth in oil consumption. Even assuming that we continue to use crude oil at the current rate, Saudi Arabia, with the largest known crude oil reserves, could supply all the world’s oil needs for only about 10 years. In short, just to keep on using oil at the current rate, we must discover and add to global oil reserves the equivalent of a new Saudi Arabian supply every 10 years.

Once crude oil has been extracted, it is transported to a refinery by pipeline, truck or ship (oil tanker). There it is heated and distilled in gigantic columns to separate it into components with different boiling points, such as diesel oil, heating oil, aviation fuel, gasoline, grease, wax, asphalt. Some of the products of oil distillation, called petrochemicals, are used as raw materials in industrial organic chemicals, pesticides, plastics, synthetic fibers, paints, medicines, and many other products.

Refining crude oil. Based on their boiling points, components are removed at various levels in a giant distillation column. The most volatile components with the lowest boiling points are removed at the top of the column.

II.

Natural gas is a mixture of 50 ¾ 90% by volume of methane (CH₄), the simplest hydrocarbon; smaller amounts of heavier gaseous hydrocarbons such as ethane (C₂H₆), propane (C₃H₈), and butane (C₄H₁₀); and small amounts of highly toxic hydrogen sulfide (H₂S).

Conventional natural gas lies above most reservoirs of crude oil. Unconventional natural gas is found by itself in other underground sources. So far it costs too much to get natural gas from such unconventional sources, but the extraction technology is being developed rapidly.

When a natural gas field is tapped, propane and butane gases are liquefied and removed. The rest of the gas (mostly methane) is dried to remove water vapor, cleansed of poisonous hydrogen sulfide and other impurities, and pumped into pressurized pipelines for distribution.

Russia and Kazakhstan have about 42% of the world's natural gas reserves. Other countries with large known natural gas reserves are Iran (15%), Qatar (5%), Saudi Arabia (4%), Algeria (4%), the United States (3%), Nigeria (3%), and Venezuela (3%). Geologists expect to find more natural gas, especially in unexplored developing countries.

The outlook for natural gas supplies is much better than for oil. At the current consumption rate, known reserves and undiscovered, potential reserves of conventional natural gas are expected to last for 125 years.

Using natural gas as energy source has a lot of advantages. First, it will last for 125 years at the current consumption rate. Second, it has high net energy yield. Other advantages are less air pollution and lower CO₂ emissions than other fossil fuels, moderate environmental impact and low land use, easy transportation.

In fairly new combined-cycle natural gas systems, natural gas is burned in combustion turbines, which are essentially giant jet engines bolted to the ground. This system can produce electricity more efficiently than burning coal or oil or using nuclear power. These systems can also provide backup power for solar energy and wind power systems. Smaller combined-cycle natural gas systems being developed could supply all the heat and electricity needs of an apartment building or office building. Most of the more than 200 new power plants, which are to be built in the United States between 2000 and 2015, will use natural gas turbines systems.

Because of its advantages over oil, coal, and nuclear energy, some analysts see natural gas as the best fuel to help make the transition to improved energy efficiency and more renewable energy over the next 50 years.

III.

Coal is a solid fossil fuel formed in several stages as buried plant remains are subjected to intense heat and pressure over many millions of years. Coal provides about 22% of the world's commercial energy, it is used to generate 62% of the world's electricity and to make 75% of its steel.

About 66% of the world's proven coal reserves and 85% of the estimated undiscovered coal deposits are located in Russia, the United States, China, and India. Coal is the world's most abundant fossil fuel. Identified world reserves of coal should last at least 225 years at the current usage rate, and 65 years if usage rate rises 2% per year. The world's unidentified coal reserves are projected to last about 900 years at the current consumption rate and 149 years if it increases 2% per year.

Coal is very abundant, but it has the highest environmental impact of any fossil fuel from 1) land disturbance, 2) air pollution, 3) CO₂ emissions (about 43% of the world's annual emissions), 4) release of particles of mercury when burned, 5) release of thousands of times more radioactive particles into the atmosphere per unit of energy than does a normally operating nuclear power plant, and 6) water pollution.

Each year in the United States alone, air pollutants from coal burning kill thousands of people (with estimates ranging from 65.000 to 200.000), cause at least 50.000 cases of respiratory disease, and result in several billion dollars of property damage. However, new ways, such as fluidized-bed combustion, have been developed to burn coal more cleanly and efficiently and may be phased in over the next several decades.

Many analysts project a decline in coal use over the next 40 ¾ 50 years because of its high CO2 emissions and harmful health effects and the availability of safer and usually cheaper ways to produce electricity such as burning gas and combined-cycle gas turbines and wind energy.

Date: 2016-01-14; view: 558