CONS
■ Steady wind is required to make the investment in wind farms
economical; few places are suitable.
■ Backup systems need to be in place when the wind is not blowing.
■ Causes visual and noise pollution.
■ May interfere with the flight patterns of birds.
■ May interfere with communication, such as microwaves, TVs, and cell
phones.Other (Future) Renewable Energy Sources
HYDROGEN FUEL CELLS
Nine million tons of hydrogen is produced in the United States each day—
enough to power 20 to 30 million cars or 5 to 8 million homes. Most of this
hydrogen is used by industries in refining, treating metals, and processing foods.
The hydrogen fuel cell operates similar to a battery. It has two electrodes—
oxygen passes over one and hydrogen passes over the other. The hydrogen reacts
with a catalyst to form negatively charged electrons and positively charged
hydrogen ions (H+). The electrons flow out of the cell to be used as electrical
energy. The hydrogen ions move through a membrane where they combine with
oxygen and the electrons to produce water. Unlike batteries, fuel cells never run
out.