Nuclear fusion: Energy of the next generatrion

The use of the fossil fuels dates back to the 1700s, the beginning of the Industrial Revolution. After exploiting fossil fuels for three centuries, human society has made great progress in development.   Fossil fuels power the power tools, fuel the vehicles, and produce electricity. The use of the fossil fuel facilitated the advance in technology and change human's lifestyle dramatically. Although our society has been benefited from the fossil fuel, we suffered from our dependence on it. As our demand for energy grows, the amount of fossil fuel burned per year grows each year. The carbon dioxide released by the combustion of the fossil fuel has broken the balance of the carbon cycle on Earth.
Consequently, the global temperature keeps rising and impacts the eco-system. If the use of fossil fuel is not cut down significantly within the next decade, the global temperature will be raised to a dangerous level. In order to restore the balance and achieve sustainable development, human society needs to seek for the low or non-carbon emission source of energy. At this moment, there are several types of zero carbon emission energy have been applied to electricity production, such as solar energy, hydropower, wind power, etc. Zero carbon emission energy, or green energy, has almost no impact on the environment. However, the energy production efficiency of green energy is usually low. Moreover, green energy is unstable and is limited to the natural resource. For example, solar power is not effective in the area that does not have a lot of exposure to sunlight. Even solar panels are built in the area that has a great sunlight exposure, the intensity of the sunlight is not consistent since it can be influenced by weathers and seasons. Therefore, green energy is not very promising in sustaining our demand for energy. Maybe there will be a significant improvement in green energy, but it does not look optimistic at this moment.
If the green energy cannot solve the problem, does it mean that we should give up? The answer is no. There is a type of energy that has a great potential for replacing fossil fuel entirely. This type of energy does not only exist in the dream or science fiction. In fact, we are feeling it and benefited from it every day. This type of energy is called nuclear fusion. Nuclear fusion is the source of the power of the sun. The nuclear fusion reaction is continuously occurring at the core of the sun and produces energy that is released in the form of light and heat. In the nuclear fusion reaction, two light atoms such as hydrogen are fused together and form a heavier atom such as helium. In this process, some masses are lost, which means that the mass of products is less than the mass of the reactance. The lost mass does not simply disappear, it is converted to the energy. The amount of energy converted can be calculated with the Einstein's formula: E=mc^2. Where m is the lost mass and c is the speed of light. From this formula, we can see that a large amount of energy is produced with a tiny loss of mass. The nuclear fusion reaction can happen between many different atoms. Among various possibilities, deuterium and tritium fusion is the most viable because it occurs most frequently. Nuclear fusion energy has many desirable properties such as producing an abundant amount of energy, zero greenhouse gas emission, and no long-lived radioactive waste production. If one ton of deutirium were to be consumed throught the fusion reaction with tritium, the energy produced would be 8.4*10^20 joules. This can be compared to the energy content of one ton of coal, 2.9*10^10 joules. The fuel for the nuclear fusion, deutirium, is abundant in the Earth ocean. Tritium, however, has to be bred from lithium or gotten from the deuterium cycle. 

To apply nuclear fusion on producing electricity, there are several engineering challenge have yet to be overcome. One of the challenges in controlling fusion reaction is controlling plasma with the temperature up to several millions degree celcius. The research on nuclear fusion energy is challenging, time-consuming, and requires lots of funding. Despite all the effort required, nuclear fusion is definitely worth pursuing due to its great potential. If the nuclear fusion energy were fully developed, it would be able to replace all the fire power plant and restore the balance of the carban cycle.