Solar Energy Essay

Solar Energy

Introduction:

The Earth captures around 342 W/m2 of energy from the sun. This energy is in the form of solar radiation, which the atmosphere reflects about 77 W/m2 and will absorb around 68 W/m2 of solar radiation annually. Therefore, the Earth’s surface is receiving, on average, about 197 W/m2 of solar radiation annually. This amount of energy received is roughly more than 10,000 times the amount of all energy humans consume per year. This energy can be used to produce electricity or heat. This energy source is not being used to it’s potential considering how much effort would come into effect to store and transport this energy.

Of course, during the daylight hours only, solar energy is directly accessible. Depending on the weather conditions and the season, the intensity of the energy varies at different locations. The solar radiation that reaches the top atmosphere is equivalent to 1366W/m2. At the equator, the radiation that reaches the ground is about 1000W/m2. In the lower atmosphere, the energy is about 0.5 W/m2 due to the thicker atmosphere. Conditions like clouds, pollution and aerosols can also reduce the amount of radiation that reaches the ground. In North America, the average solar energy available varies from 3000 to 9000 Wh/m2 per day. In Northern Europe, solar energy varies from 2000 to 3000 Wh/m2 per day. In contrast, the tropics receive around 6000 Wh/m2 per day. There are a lot of different ways to use solar energy. Some technologies are used to produce heat from solar energy. Other technologies use solar energy to produce electricity.

Thermal Solar Energy

Hot Water Heaters: The easiest way to exploit solar radiation is as thermal energy. One way to harness this solar energy is to heat water. Aro...

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...ct solar radiation onto a single point above the mirror. The parabolic dish receiver is ran by a computer and uses a dual-axis system for tracking the sun. A Stirling engine is used for some of these systems to generate electricity. With these receiver focal points, temperatures can reach higher than 100°C. At this temperature, energy created is efficient.

Photovoltaic Systems

The photovoltaic effect, electricity can be created directly from sunlight. Some semi-conductor materials that are exposed to sunlight can create electron-hole pairs, which can be collected to produce electricity. This occurs when photons have energy above a certain threshold. These photons have shorter wavelengths. In silicon, the threshold for electron-hole production is in the infrared region of the electromagnetic spectrum.

Silicon:

Electricity Storage

Economy and Environment

Conclusion