The era of solar power

Resources stored on the earth such as coal and gas, rivers and water streams, uranium and thorium mines are being exploited to create thermoelectric, hydroelectric and nuclear power sources. will come to exhaustion. Only the wind and sunlight remain .

Sun: Endless energy source

Along with the wind, sunlight is a ' natural ' resource, too cheap or almost no price.

The light source or energy source emanating from the Sun is almost endless with the 'infinity' of the Sun itself. Because this energy source is generated by fusion fusion in the Sun, it will last until the fuel burns out, calculated from now until then, about . 5 billion years!

The Earth, though receiving only a very small fraction of the total solar energy emitted, but that 'small part' for the needs of all human beings is also extremely large. Indeed, the portion of the solar energy that reaches the planet is as large as 174 Petawatt (PW).

To visualize the magnitude of the figure, please recall the following energy power units: Kilowatt = 103 watts, Megawatt = 106 watts, Gigawatt = 109 watts (or 1 billion watts), Terawatt = 1012 and Petawatt = 1015 watts (or 1 million Gigawatt).

About 30% of the solar energy to the earth is reflected back into outer space, the rest is absorbed by clouds in the atmosphere, by the water in the oceans and the earth's surface layers.

The form of solar energy to the surface of the earth is light photons, in physics called electromagnetic photons, distributed in a wide spectrum, mainly in the form of visible light, followed by near-infrared light and a small part is near-ultraviolet light.

For many years, the methods of human use of solar energy have varied and plentiful, simple such as cooking, heating and cooling and complexity such as making balloons, storing heat with ordinary salt. or molten salt, etc.

The estimated total global solar energy exploits on such non-electrical applications, for a year; in 2007, for example, 150 - 200 Gigawatt (GW) was 200 billion watts.

But the most important way of using solar energy today and in the future is to produce electricity. Here, two types of solar power production technology are widely developed, namely: Technology for converging CSP solar (concentrated solar power) and SPV photovoltaic technology (Solar Photovoltaic).

SPV solar power technology

In Photovoltaic Technology, the energy of sunlight is converted into electric current, thanks to the photoelectric effect, through photovoltaic cells or tiny solar cells. Small batteries are assembled into large solar panels. These large panels are assembled together into modules or ranges.

Initially, solar panels were used for artificial satellites or spacecraft. Now, in the electric power industry, the main use of solar panels is to supply electricity to the common grid thanks to the converter from direct current in the battery to alternating electricity.

Currently, the cost of solar electricity is still much higher than the price of traditional electricity, but in some countries such as Japan or Germany with financial incentives, the output of the solar power industry has has made great progress in recent years. Worldwide, the estimated total solar power capacity using photovoltaic technology exceeded 100 Gigawatt (GW).

The number of solar power plants using photovoltaic technology with a capacity of 50MW or more has reached 38. In particular, the plant with the largest capacity (250MW) belongs to the Agua Caliente Solar Project, in Yuma County, AZ ( USA). But the country with the most of this type of factory is Germany with 14.

CSP solar power technology

CSP (concentrated solar power) solar energy technology is also known as STE solar energy technology (Solar thermal energy). This technology uses a system of multiple lenses, reflectors and tracking systems to focus sunlight on a large area into a small area.

In this area, water or other special liquid contained in tanks or pipes is heated to temperatures from a few tens of degrees or several hundred degrees depending on the intended use, such as pool heating, provided. Warm water for households, store room energy when there is no sun shining or forming strong steam streams that spin turbines to produce electricity in power plants.

Commercial power plants using CSP technology were first developed in the 1980s. There are now the largest factories such as Solar Energy Generating Systems in the world, located in the Mojave desert of California, USA, with a capacity of 354 MW. Estimated total solar power capacity with CSP technology in the world has reached 2,227 Gigawatt (GW) capacity.

Number of solar power plants using CSP technology with capacity of 100MW or more reaches 12. In which, the plant with the largest capacity (354MW) in Mojave Desert, California (USA). But the country with the most of this type of factory is Spain with the number 11.

Thus, Solar Power, a new form of clean energy because of no greenhouse gas emissions, is a strong trend in the world, especially in developed industrial countries such as Germany, America and Spain. , Italy, Japan.

Vietnam, our country in the tropics is sunny and windy, converging many conditions to develop this power source.