The sun beams down enough energy every hour to satisfy the whole planet’s global energy needs for an entire year.
Solar energy is the technology used to harness the sun’s energy and make it productive. However, we are only utilizing solar energy to provide only one tenth of one percent of all the global energy demand.
Most people are familiar with solar panels, or photo voltaic cells, used on things like spacecraft, rooftops and handheld devices like calculators. The cells are made up of semiconductor materials like those found in computer chips.
When the sunlight shines on the cells, electrons are knocked loose from their atoms. The electrons then generate energy, as they flow through the cells.
On a much larger scale, solar thermal power plants use various techniques to concentrate the sun’s energy as a heat source. The heat is then used to boil water to drive a steam turbine which generates electricity in much the same way as coal and nuclear power plants, supplying electricity to thousands of people.
One technique uses long troughs of U-shaped mirrors that focus sunlight on a pipe of oil that runs through the middle. The hot oil then boils water to provide electricity generation.
Another technique uses movable mirrors to focus the sun’s rays on a collector tower where a receiver sits. Molten salt, flowing through the receiver, is heated to run a generator.
Solar energy is an inexhaustible source of fuel that is pollution and often noise free. The technology is also very versatile. For example, solar cells are capable of generating energy for out of the way places like satellites in the Earth’s orbit and homes in the middle of nowhere, as easily as they can power buildings in large cities and futuristic vehicles.
However, there are drawbacks to solar energy, it doesn’t work at night without a storage device like a battery. Cloudy weather can also make the technology unreliable during the day. Solar technology is also expensive and requires a lot of space to collect enough of the sun’s energy to be useful to a lot of people.
However, despite these drawbacks, solar energy use has surged roughly 20 percent, year over year, for the past 15 years This is due to the rapidly falling prices of the technology and the gains in efficiency.
Japan, Germany and the United States are currently major markets for solar cells. With tax incentives, solar electricity can often pay for itself in five to ten years.