Sun is ours closest star and directly or indirectly source of almost all available energy on Earth. Sun’s energy originates from nuclear fusion in its core, where temperature reaches 15 millions °C. Nuclear fusion is process of joining two light atoms into one heavier atom.
Thanks to nuclear fusion on Sun, every second about 600 million tons of hydrogen is transformed into helium, having 4 million tons of hydrogen transformed into energy as side effect.
Solar energy facts:
- The Sun has been producing energy for billions of years now and by current estimations it will continue to do that for next five billions of years. Solar energy is part of energy produced on the Sun that reaches the Earth.
- Solar energy can be directly converted into thermal energy or into electrical energy which are useful forms of energy. Electrical energy is most useful form of energy because it can be easily converted into useful work.
Solar energy can be directly converted into thermal energy or into electrical energy.
- Solar energy is “the engine” beyond almost all renewable energy sources. Secondary solar energy powered resources such as wind energy, wave power, hydroelectricity and biomass, account for most of the available renewable energy on earth. Geothermal and tidal energy are not considered as secondary products of solar energy because they exist even without solar radiation.
- At nights and on very cloudy days solar energy is not fully available and energy storage systems are very important to save energy when it is available. Solar energy can be stored in many forms, but most common are conversion to thermal energy, storing electrical energy in rechargeable batteries and pumped storage systems – pumping water to higher elevation when solar energy is available and using this water when solar energy is not available.
Solar energy is renewable energy source because it cannot be depleted like fossil fuels. Solar energy is also very clean source of energy after installation because there are no harmful emissions or pollution caused by using solar panels or solar cells.
- There are three basic types of solar energy usage:
- Solar panels – Direct conversion of solar energy into heat. Mostly used for water heating.
- Concentrating solar power – Focusing solar radiation using arrays of mirrors to superheat some fluid. Superheated fluid is then used to generate electricity. This is the main method used in today’s solar power plants.
- Solar cells – Conversion of solar energy directly into the electricity.
- We can roughly estimate that earth surface is receiving around 100,000 TW of solar power at each moment (upper atmosphere receives around 174,000 TW, but gases, clouds, pollution and other factors decreases available power on the surface). Whole population of earth uses 400 qbtu of energy each year – to get this energy we need constant power source of 13.38 TW – about 8000 times less than we get from the sun at each given moment. From numbers above we can calculate that in only 71 minutes we receive enough solar energy to satisfy energy needs of entire population for one year.
- Solar power is the main energy source for satellites and spacecrafts after launch. For example, latest GPS satellites (Block IIR) use solar cells generating 1136 watts. Solar cells are almost always used in combination with batteries to avoid power outages when satellite or craft is not in the direct view of the Sun.
We can significantly reduce energy dependence just by using cheap solar panels.
- About 30% of total energy consumption is used to heat water. From that we can see that we can significantly reduce energy dependence just by using cheap solar panels for that purpose. There is no need for expensive solar cells to generate electricity and then use this electricity to heat water.
- Solar energy is very clean energy source after installation, but there are some concerns how clean the manufacturing process for solar cells is. Solar panels are in many ways directly descended from semiconductors, and making them produces toxic byproducts that could endanger living beings and also greenhouse gases are released.
- Solar power will be used at much larger scale in the future because of new scientific researches that should decrease the costs and increase the efficiency of the solar power systems.
- In his years in the Vatican, Leonardo Da Vinci (1452 – 1519) planned an industrial use of solar power, by employing concave mirrors to heat water. In modern days this principle is used in solar power plants and it is called concentrating solar power (CSP). Da Vinci planned that because he worried about the destruction of the earth’s vast forests in humanity’s search for fuel. Sound familiar?