fossil fuels were formed before and during the time of the dinosaurs – when plants and animals died. Their decomposed remains gradually changed over the years to form coal, oil and natural gas. Fossil fuels took millions of years to make. We are using up the fuels formed more than 65 million years ago. They can't be renewed; they can't be made again. We can save fossil fuels by conserving and finding ways to harness energy from seemingly "endless sources," like the sun and the wind.
We can't use fossil fuels forever as they are a non-renewable and finite resource. Some people suggest that we should start using hydrogen.
Hydrogen is a colorless, odorless gas that accounts for 75 percent of the entire universe's mass. Hydrogen is found on Earth only in combination with other elements such as oxygen, carbon and nitrogen. To use hydrogen, it must be separated from these other elements.
Today, hydrogen is used primarily in ammonia manufacturing, petroleum refining and synthesis of methanol. It's also used in NASA's space program as fuel for the space shuttles, and in fuel cells that provide heat, electricity and drinking water for astronauts. Fuel cells are devices that directly convert hydrogen into electricity. In the future, hydrogen could be used to fuel vehicles (such as the DaimlerChryslerNeCar 4 shown in the picture to the right) and aircraft, and provide power for our homes and offices.
Hydrogen can be made from molecules called hydrocarbons by applying heat, a process known as "reforming" hydrogen. This process makes hydrogen from natural gas. An electrical current can also be used to separate water into its components of oxygen and hydrogen in a process called electrolysis. Some algae and bacteria, using sunlight as their energy source, give off hydrogen under certain conditions.
Hydrogen as a fuel is high in energy, yet a machine that burns pure hydrogen produces almost zero pollution. NASA has used liquid hydrogen since the 1970s to propel rockets and now the space shuttle into orbit. Hydrogen fuel cells power the shuttle's electrical systems, producing a clean by-product – pure water, which the crew drinks.
You can think of a fuel cell as a battery that is constantly replenished by adding fuel to it – it never loses its charge.
Hydrogen Fuel Cell
Fuel cells are a promising technology for use as a source of heat and electricity in buildings, and as an electrical power source for vehicles.
Auto companies are working on building cars and trucks that use fuel cells. In a fuel cell vehicle, an electrochemical device converts hydrogen (stored on board) and oxygen from the air into electricity, to drive an electric motor and power the vehicle.
Although these applications would ideally run off pure hydrogen, in the near term they are likely to be fueled with natural gas, methanol or even gasoline. Reforming these fuels to create hydrogen will allow the use of much of our current energy infrastructure – gas stations, natural gas pipelines, etc. – while fuel cells are phased in.
In the future, hydrogen could also join electricity as an important energy carrier. An energy carrier stores, moves and delivers energy in a usable form to consumers.
Renewable energy sources, like the sun, can't produce energy all the time. The sun doesn't always shine. But hydrogen can store this energy until it is needed and can be transported to where it is needed.
Some experts think that hydrogen will form the basic energy infrastructure that will power future societies, replacing today's natural gas, oil, coal, and electricity infrastructures. They see a new "hydrogen economy" to replace our current "fossil fuel-based economy," although that vision probably won't happen until far in the future.
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