Transportation uses a huge amount of energy—powering our cars, boats and planes and getting us where we need to go. We even transport energy sources themselves—for example, delivering crops to the plants that make biodiesel and then shipping the biodiesel to the companies that use them! But how is fuel for transportation created—and what is it created from? Energy for transportation is created from a variety of sources, including solar, biofuels, petroleum and more.
Vehicles using solar power include cars, bicycles and even spacecraft (which use solar panels in conjunction with electric propulsion)! Solar-powered cars use photovoltaic cells to turn sunlight into electricity. Solar vehicles are not currently a viable option for everyday transportation, because PV cells are expensive to create and it’s difficult to create solar panels that are big enough to collect the sunlight vehicles need to run regularly. Vehicles that combine solar power with electric power could prove to be successful for transportation—the future will tell.
Biofuels have a long history in transportation—the first diesel engine ran on peanut oil in the late 1800s, and Henry Ford’s Model T was designed to run on ethanol in 1908—and it has been gaining in popularity in recent years. The biofuel ethanol is created by fermenting starch or sugar crops such as sugarcane, barley, rice and other grains. Biodiesel is made by mixing cooking grease, vegetable oil or animal fat with alcohol. Both these biofuels are usually added to other fuels to cut down on vehicle emissions, but they can also be used in their pure form in some engines.
Algae can also be used to create biofuels. California-based company Sapphire Energy aims to produce 1 million gallons of algae-based diesel and jet fuel by 2011 and 100 million gallons a year by 2018. Algae can be grown in areas that are deemed unsuitable for growing plants or crops. This is a benefit over other biofuels, which are produced on farmland that could be used for food crops or forest land that has been cleared of trees (causing environmental concerns).
Even coal can be used as a fuel for transportation! Coal liquefaction, the process of converting coal to liquid, can create fuels for cars and jets. The only commercial coal liquefaction industry in the world is located in South Africa, and it has been producing fuels since 1955.
Of course, by far the most common fuel for transportation is petroleum. In the United States, 97% of the energy that moves the transportation sector (cars, buses, subways, railroads, airplanes, etc.) comes from fuels made from oil. Auto manufacturers are developing cars to run on alternative fuels such as hydrogen and ethanol or even powered by electricity. But the batteries in electric cars need to be charged, and the fuel to generate the electricity comes from oil or gas. Also, the hydrogen needed for fuel cells may be generated from natural gas or petroleum-based products. Even as alternative fuels are developed, oil will be crucially important to assuring that people can get where they need to be and want to go for many years.