At present, human beings are living in a society which is developing rapidly, facing a severe crisis of energy. As the population is increasing in a high speed, the ecological environment has been damaged by human activity. At the same time, with industry highly developed, the environment has been polluted seriously. Therefore, other alternative energies should be found instead of fossil fuels, which is green, efficient and renewable. Thus, people began to discover the importance of renewable energy sources, for instants, solar, biogas and water. In fact, the majority of renewable energy sources come from the solar energy, which means they can be exploited for centuries and even millennia. In this essay, wind energy and solar energy are put in a comparison. Both of them are clean energy and environmentally-friendly, although they differ in cost and efficiency.

The first important similarity of wind energy and solar energy is that both of them are renewable. Solar energy is the most abundant energy resources that human can make use of. It is estimated that during the past thousands of years the sun consumes only 2% of its own energy (Duncan, 2002). In the next few billion years there will not be significant changes to the sun, so the sun can be used as a permanent source of energy. Likewise, wind energy is also unlimited. Because it is generated by air flow on the Earth’s surface. Wind is everywhere, no matter it is in the vast grasslands or mountains. Wind power can be extracted by wind mills. As the wind makes wheels rotating, it is changing the wind power into electric power. Obviously, these two kinds of energy both come from the nature, which are totally recycled.

Another similarity is that both wind energy and solar energy cause almost no pollution to the environment. Compared to the environmental effects of traditional energy sources, the environmental effects of solar energy and wind energy are relatively minor. Coal, oil and other fossil fuels emit harmful gases and residue, while the use of solar energy will not bring about pollution. Moreover, it will not produce any adverse effects on the environment, which is a clean source of energy. Meanwhile, after the extensive use of solar energy, the temperature will be slightly increased, although this temperature will not cause adverse effects on the environment and the ecological balance (Friis-Christensen and Lassen, 1991). Wind power consumes no fuels, and emits no polluted air. Wind energy is abundant, almost endlessly used, widely distributed and clean. Furthermore, both of them don’t produce carbon dioxide, which do not cause the greenhouse effect. All in all, both of them bring peace to the environment.

In spite of these similarities, wind energy and solar energy are different in some aspects. At present, the use of solar energy technologies has the disadvantage of high cost. Topfocus (2007) stated that the cost of generating electricity by solar power is about 7-12 times higher compared to the normal electricity, and 6-10 times higher compared that of generating electricity by wind power. Furthermore, in many rainy areas with short period of sunshine, it is very difficult to completely rely on solar power supply. This means unless there are a large number of solar panels or there is a more sophisticated solar energy technology, it is still difficult to produce a large number of power supplies to meet the daily needs. In addition, solar panels have a limited lifespan, which is about 10-20 years. This means the cost to deal with the technical problems is extremely high (Brignall, 2010). In contrast, the wind turbines have longer lifespan, although it requires a lot of land to build. As long as the turbines have been built, it can be used for hundreds of years. In the short term, the base costs of wind turbines are relatively cheap. (Alvesta, n.d.)

Another difference exists in the efficiency. Using solar energy is more efficient than wind energy. According to Duncan (2000), about 70% of sun’ energy can be received by the earth. In order words, more power can be collected by the solar panels. Furthermore, the materials used on the solar panels are silicon, which has less resistance in the power generation process (Ffbing, 2009). Compared to the solar energy, wind energy has short effective time and need to be built near the sea. When wind power is transformed into electric power, the efficiency is only about 20 % (Chapo, 2006).

In conclusion, after comparing solar energy and wind energy, both of them have advantages and disadvantages. The solar energy solve the problem that human will not afraid there are no energy to use. However, the technologies still need to improve. Using wind energy is cheaper and more direct, although it needs high technology to be more efficient. At present, China’s environmental pollution problems highlight the fragility of ecosystems. A large number of mining and the use of fossil fuels make a great impact on the environment, especially in China’s energy consumption structure. The high proportion of coal, carbon dioxide emissions growing faster, which has a great impact on climate change. Development and utilization of renewable energy plays an important role in optimizing energy structure and protecting the environment, which reduces greenhouse gas and cope with climate changes. In my opinion, the renewable energy will play an important role in people’s life and let human have a better future.