Hydrogen is the simplest element. An atom of hydrogen consists of
only one proton and one electron. It's also the most plentiful element
in the universe. Despite its simplicity and abundance, hydrogen doesn't
occur naturally as a gas on the Earth - it's always combined with other
elements. Water, for example, is a combination of hydrogen and oxygen (H2O).
Hydrogen is also found in many organic compounds, notably the hydrocarbons
that make up many of our fuels, such as gasoline, natural gas,
methanol, and propane. Hydrogen can be separated from hydrocarbons
through the application of heat - a process known as reforming.
Currently, most hydrogen is made this way from natural gas. An
electrical current can also be used to separate water into its
components of oxygen and hydrogen. This process is known as electrolysis. Some algae and bacteria, using sunlight as their energy source, even give off hydrogen under certain conditions.
Hydrogen is high in energy, yet an engine that burns pure hydrogen
produces almost no pollution. NASA has used liquid hydrogen since the
1970s to propel the space shuttle and other rockets into orbit. Hydrogen
fuel cells power the shuttle's electrical systems, producing a clean
byproduct - pure water, which the crew drinks.
A fuel cell combines hydrogen and oxygen to produce electricity,
heat, and water. Fuel cells are often compared to batteries. Both
convert the energy produced by a chemical reaction into usable electric
power. However, the fuel cell will produce electricity as long as fuel
(hydrogen) is supplied, never losing its charge.
Fuel cells are a promising technology for use as a source of heat and
electricity for buildings, and as an electrical power source for
electric motors propelling vehicles. Fuel cells operate best on pure
hydrogen. But fuels like natural gas, methanol, or even gasoline can be
reformed to produce the hydrogen required for fuel cells. Some fuel
cells even can be fueled directly with methanol, without using a
reformer.
In the future, hydrogen could also join electricity as an important
energy carrier. An energy carrier moves and delivers energy in a usable
form to consumers. Renewable energy sources, like the sun and wind,
can't produce energy all the time. But they could, for example, produce
electric energy and hydrogen, which can be stored until it's needed.
Hydrogen can also be transported (like electricity) to locations where
it is needed.
Flowing water creates energy that can be captured and turned into electricity. This is called hydroelectric power or hydropower.
The most common type of hydroelectric power plant uses a dam on a
river to store water in a reservoir. Water released from the reservoir
flows through a turbine, spinning it, which in turn activates a
generator to produce electricity. But hydroelectric power doesn't
necessarily require a large dam. Some hydroelectric power plants just
use a small canal to channel the river water through a turbine.
Another type of hydroelectric power plant - called a pumped storage plant
- can even store power. The power is sent from a power grid into the
electric generators. The generators then spin the turbines backward,
which causes the turbines to pump water from a river or lower reservoir
to an upper reservoir, where the power is stored. To use the power, the
water is released from the upper reservoir back down into the river or
lower reservoir. This spins the turbines forward, activating the
generators to produce electricity.
A small or micro-hydroelectric power system can produce enough electricity for a home, farm, or ranch.
