Solar energy is energy that is collected from the sun and converted into a form of thermal or electrical energy. Many people think of solar panels when solar energy is mentioned. However, in addition to solar panels, solar energy also includes wind power, hydropower and others. Wind power is caused by fluctuations in temperatures where hot and cold air masses will move. The movement causes wind, which can lead to wind power. Ocean and water currents are also affected by sunlight. When areas of different temperatures interact, waves or water movement can happen. Solar energy includes any type of energy that is created or collected because of the power of the sun. Solar energy can be broken down into four categories: direct, indirect, active, and passive.
Direct Solar Energy
When sunlight is collected in only a single step and then transformed into energy, this is known as direct solar energy. Some examples can include the following methods. Sunlight striking a photovoltaic cell and converted to electricity is one example. Another happens when sunlight is absorbed by a dark surface and then warms water stored in a solar thermal collector. Sunlight can be directly absorbed by a fiber optic cable placed outside a building and the light is transmitted inside along the cable.
Indirect Solar Energy
When there is more than one-step involved in collecting and converting sunlight into energy, it is known as indirect solar energy. Plants exhibit indirect solar energy because they collect sunlight, convert it into chemical energy, and become bio fuel. After billions of years, these plants turn into fossil fuels. Another example is hydroelectric energy that relies on turbines. Oceans are another source of indirect solar energy where differences in water temperatures cause wave movement.
Active Solar Energy
Any systems that require the aid of other energy besides the sun are considered active forms of solar energy. Some of these forms may have tracking devices to help the collector remain aimed at the sun or may involve the use of pumps, blowers, and other materials.
Passive Solar Energy
Passive forms of solar energy are the most common forms of solar energy. Passive forms require no other aid in order to generate solar energy. When a home is warmed by sunlight passing through a window (termed daylighting), this is an example of passive solar energy. Some water heaters that are solar based also use sunlight to heat the water but have no pump to circulate the water.
Early Uses of Solar Energy
Solar energy has been in use by Mother Nature since the planet began. Plants use photosynthesis to survive. The plants store the energy collected and over many millions of years, the plants become fossil fuels, which are in such demand today. Because of the extreme length of time involved in recreating new fossil fuels, alternatives are actively being sought out. Ancient Greeks and Romans built their homes to take advantage of passive solar energy. The Romans were the first to introduce glass for windows to allow its people to use the sun to warm their homes more efficiently. A law was even put in place that made it illegal to block a neighbors access to sunlight. Rome was also the first to build great greenhouses that allowed the right conditions to be created for growing of plants from all around the Roman Empire's lands.
In the early 1900s, the solar hot water heater was first discovered. In 1950, several Americans working on the development of transistors found that the use of silicon allowed the creation of a solar cell (also known as photovoltaics - PV cell).
Modern Usage of Solar Energy
Today, new technologies are constantly being introduced that are making solar energy more efficient and easier to use. Solar energy has become more popular with the introduction of the 'green' movement. Finding ways to reduce our dependence on fossil fuels and exploring alternative clean renewable sources of energy is the primary goal of the green movement. Many homes and business now have solar roof shingles, solar paint, and even solar nanotechnology to help reduce a home or business' need for electricity. Many skyscrapers are being built with powerglass instead of normal glass windows. The powerglass is a thin polymer photovoltaic layer, which is applied to the glass being used in windows, walls, and on roofs. Entire office buildings can become power plants that gather electricity throughout the day and store excess power for later use.
Advantages of Solar Energy
Solar energy has many advantages to its use. It is non-polluting and environmentally friendly; no emissions are generated when using solar energy. Unlike fossil fuels, energy from the sun is renewable and will not run out any time soon. The power of solar energy comes from our sun and does not damage or harm the environment during its collection.
Solar energy is an economical alternative to fossil fuels. Electricity generated through solar power is cheaper per kilowatt-hour than any other type of energy currently generated. One can begin to see immediate returns when investing in solar power.
Solar power is very easy to access because the sun shines on the entire planet. No one controls where sunlight falls so everyone can access sunlight for use in creating electricity generated by solar power. Because the sun provides the solar energy free, no one has to worry about supply and demand changing the cost of solar power.
So many reasons exist why solar energy is the alternative fuel method that the entire planet should be using. Many governments have tax rebates and incentives for homeowners to implement solar energy including the installation of solar panels. Any excess power that is collected can also be sold back to the energy concerns to help further reduce electrical cost. Many third world countries can leap past the pollution that other industrial countries experienced by moving directly toward solar power and avoiding the use of fossil fuels.
Disadvantages of Solar Energy
As with most things, some disadvantages currently exist concerning solar power. The primary disadvantage is that not every part of the planet's surface receives the same amount of sunlight as others. This can make it difficult for some areas to take advantage of solar energy. Storing the power collected by solar collectors is another shortfall that technology is making great strides in.
Most devices or systems that collect and convert solar energy do have some working pieces that need to be maintained. Although the number of parts continues to decrease as new technologies are implemented. Solar power is not always consistent enough to run on alone. Depending on the weather and other conditions, one might have to rely on current electrical methods to make up the difference. This lack of reliability will decrease as better collectors and improved storage solutions are created.
Methods of Solar Conversion
Two primary ways exist to convert solar energy into energy that can be readily used by humans. The two methods include solar thermal and photovoltaic. Solar thermal involves taking sunlight and using it to generate heat directly. Some examples include allowing sunlight to heat water panels that will spread the heat throughout a building to keep it warm. Sometimes the water is replaced with a non-toxic anti-freeze liquid. The energy gathered can be stored and released later in the day or the night after the sun has set.
Photovoltaic describes the method of converting the energy of the sun into electrical power. Solar cells are often used to help absorb the sunlight but not the heat of the sun. Solar power will excite the electrons of the solar cell and this will allow the production of electricity. The current provided is known asdirect current (DC) and has to be transformed into alternating current (AC) to be used by most systems. This is accomplished by sending the DC energy into aninverter.
Focusing Solar Energy
Three types of focus are possible concerning solar energy. Some applications or systems will require point focus, line focus, or non-focus types. A point focus type refers to dishes or saucer-shaped devices that concentrate or focus sunlight into a single point of solar radiation. Then a solar thermal collector device of some sort uses concentrated heat. A line focus type is a great deal like the point focus except that instead of a round dish, an elliptic or elongated dish is used. Instead of concentrating radiation at a center point, an area in the middle often in the shape of a line is used (which can concentrate the heat on a pipe to heat its contained liquid, for example). Non-focus types are the most commonly recognized forms. They can include solar collectors, solar thermal panels, and solar cell panels. This last group requires little or no focusing in order to take advantage of the power being generated by the sun.
A Reminder
As a reminder, everyone needs to be more energy conscious and we all need to improve our green related activities. Fossil fuels have a limited life and they will take many millions of years to replace. Exploring new technologies that allow us to use the limitless power of the sun are the best chance we have for solving our energy problems.
