Current method of obtaining energy
Energy source plays a very important role in human’s life. For example, people need energy source to provide heat which is necessary for human. The main method to obtain energy is getting them from coal, fossil oil, natural gas and hydroenergy. Currently, some new methods are deveoped which are nuclear energy, solar energy and wind energy. But there is question here, although there are a lot of different ways to obtain energy, people still lack of energy source. What’s more, the pollution is a very big problem.
Energy shortage and pollution
In the last 20 years, the problem of energy shortage is very serious in the whole world. The reason why it happen is the main energy sources for people are still coal, fossil oil, natural gas, and these kind of sources need to take a long time to form and they are not renewable. What’s worse, during the development of human’s life, we will consume energy source more and more rapidly. For example, in order to meet the requirements for most people, the cars which need a lot of energy become more and more widespread in the world. In these process, the pollution issue should not be ignore. Global climate change a lot in these years, and carbon dixocide, sulfur dioxide, and nitrogen dioxide are the main elements to casue green house effect. Most part of these gas is coming from the heating or using the energy source which are coal, fossil oil and natural gas. If people continue using these kind of energy source, the global warming problem will become more and more serious. Glacier will melt, sea surface will rise, and some other unpredictable issue will happen. So it is time to make some change.
These years, scientists found a new method to obtain energy which is bioenergy. Bioenergy is a form of renewable energy and it will make less pollution than the tranditional energy sources. Alcohol is an example for bioenergy, it is an alternative energy source to fossil oils. There are some benefit here, alcohol can be used as a single energy source, and it can also be used with other source such as gasoline. Then alcohol can be produced by fermentation of sugar. Fermentation is easy to achieved and people already have a very effeincy way to do fermentation. What’s more, when we use alcohol as energy source, the pollution is very less than the tranditional energy source. But there are some draw back for using the alcohol. First of all, alcohol can't provide the enough amount of energy as the tranditional energy sources do. Secondly, people need more space to contain the alcohol. The last but not the least, the techonology of making alcohol is not perfect now. 
Plant is important
During this hard time, there is a challenge concept-- the tranditional sources fossil oil, coal and natural gas are not chemical material, they are biological product, so we can consider them as bioenergy and make them renewable. Because all of these source come from plants, and then we can get the energy source by planting. If we think from the start, the most important reason that plant can make energy is plant can transfer the solar energy to the energy that people can directly use. In this process, plant don't need many extra energy input, and it can make a lot of energy by consume a little energy. According to this idea, people may make a fundamental change of the method of getting energy source, and we can do a Green Revolution which means more energy and less pollution.
There is a problem here, we don’t have enough land for planting energy plants. Currently, the land is already used for human life and biodiversity. If we make more and more energy plant, we may damage the current biodiversity conservation. People need more information and analysis to find which kind of plant is more efficient of biomass to consume and use the least area of land. Although there are some disadventages and unpredictable issue may happen in the process of doing the research of energy plant, this method still have it’s value and I think it is worth to research in the future. I feel in the future, the energy plant will play a very important role, and we can use this method to make our world more beautiful and healthy. We should not look down upon our cute and useful plants.