Petroleum. The black snake. Oil, that is – black gold, Texas tea. Love it or hate it, there’s no denying the significance of petroleum to global technology, economics, and culture. So, it’s worth it to clear away all the passion, narratives, and nicknames, and learn the facts.
Where does Oil and Petroleum come from?
The basic recipe for petroleum is the same as the other two fossil fuels, natural gas and coal: Take a swamp or ocean floor full of dead plants and animals, bury it under sand and rock, and compress it into the heat of the earth’s core for about 300 million years, give or take a few million. That recipe will get you a fossil fuel, but to make sure it turns out as liquid petroleum instead of a solid or gas, a couple other criteria need to be met. First, the organic material, or biomass, should be more animal than plant. Most petroleum reserves come from the prehistoric ocean floor, and the more of the biomass comes from marine animals rather than plants, the more likely it is to develop into petroleum. To make absolute sure your recipe yields petroleum, keep the heat on a low setting. The higher the heat, the lighter the oil – and if the heat is too high, you get natural gas.
How does it create energy?
When petroleum starts its journey in a refinery, it is a thick, molasses-like substance called crude oil. Refineries heat crude oil in a tall distiller. As it heats, it separates out into its heavier elements at the bottom, its lightest gases on top (like propane, which is used for heating and cooking), and in the middle, liquid oil. Almost all the liquid oil is processed into vehicle fuel like gasoline and jet fuel. A small amount of liquid oil is converted into electricity at power plants.
Power plants use the same three types of engine to convert the carbon in oil into electricity as they do its sister fuel, natural gas – conventional steam generation units, gas turbines, or combined-cycle technology.
In conventional steam generation units, the oil is burned in close enough proximity to water that the water boils. This creates steam, which spins a turbine and powers a generator. In gas turbines (also called combustion turbines), power plants cut out the middle man of steam. Instead, the oil is burned using both heat and pressure to produce hot exhaust gases which directly spin a turbine and power a generator. And in combined-cycle technology, power plants first burn oil using a gas turbine, powering a generator with exhaust gases. Then, the excess exhaust gases are recovered and directed into a boiler, where they heat water to generate steam and power a second turbine.
What’s the environmental cost of petroleum?
The environmental impact of petroleum production and use rivals that of natural gas, but is less harmful than coal. The first culprit here is the refining process. Oil refineries release toxins into the atmosphere in the process of turning crude oil into useful fuels. Once oil is processed into gasoline and used to power vehicles, it releases carbon dioxide into the atmosphere, the most common greenhouse gas that contributes to global warming. Finally, there is the pollution caused by mining and transporting oil. Drilling for oil damages ecosystems even when it’s done perfectly, with every precaution in place. When mining or transportation of oil goes wrong – which it does, often – oil spills cause major ecological damage. These spills harm wildlife and poison water sources.
What are its common uses?
While petroleum is the power source of choice for 40 percent of the United States’ energy needs, almost all of that petroleum is used as fuel for vehicles. In 2015, 47 percent of petroleum consumed in the U.S. was processed into and used as gasoline. 20 percent became heating oil and diesel fuel, and 8 percent became jet fuel. Refineries also process petroleum into materials for plastics, synthetic materials, and asphalt. A small amount of petroleum is still used to generate electricity.
How much does petroleum cost?
The global cost of oil increased sharply during the first decade of the 2000s, with high gas prices dominating the news cycle. Since then, the cost of petroleum has steadily decreased, but it’s still the most expensive fossil fuel.