After crude oil is extracted from the Earth, it is burned and used to boil water to produce steam, which is then pressurized and used to turn a turbine that is hooked up to a generator to transfer the mechanical energy into electrical energy. Oil is very combustible and gives off a lot of heat. When the oil is burned, exhaust gasses are produced along with the heat, and the gases are piped away from the boiler, filtered and released into the atmosphere.
Crude oil that is extracted from underneath the Earth's surface is made up of fossilized organic material. Because this oil is naturally occurring, it is technically a renewable resource. However, it takes millions of years to form and is depleting faster than it is being created, which means many consider it to be a nonrenewable and inefficient resource.
When the oil is extracted from the ground, it is piped into a burner. Burning the oil creates heat, which is used to boil water. When the water is boiled, it creates steam that expands in narrow pipes, creating a lot of pressure. The pressurized steam is then used to turn the blades of a large turbine. The turbine is hooked up to a generator which transforms the mechanical energy into electrical energy. Finally, that electrical energy is transformed into a very high voltage and stored in a national grid, which is hooked up to homes and businesses around the nation.