As we all know, the development of biofuels can not only alleviate energy shortage and solve environmental problems, but also form a new economic growth point, which has many benefits and attracted many countries. According to Kenyan media reports, some African countries believe that developing biofuel industry can increase fiscal revenue, support agricultural development, create employment opportunities and reduce dependence on fossil fuels. These African countries are actively seeking capital and technology to develop the biofuel industry. For example, Ghana, a West African country, will cooperate with Brazil to build Ghana's first sugarcane-based biofuel project in June.
It is reported that countries in Africa that have biofuel projects or are planning biofuel projects include Nigeria, Mali, South Africa, Kenya, Mozambique, Senegal, Democratic Republic of the Congo, Malawi, Zambia and Zimbabwe.
However, some experts believe that using corn and other crops as raw materials to develop biofuels will inevitably lead to the contradiction between energy and people competing for food, which is an urgent problem for relevant countries. In addition, although some other projects use cassava, jatropha curcas and other crops as raw materials, they also need to occupy cultivated land, and these raw materials are inefficient and have no obvious economic benefits under the current technical conditions.
In recent years, people's doubts about biofuels have gradually increased. On the one hand, people realize that although biofuels are much cleaner than fossil fuels, the process of producing biofuels is not so "clean", which consumes a lot of water and fossil fuels and even leads to the destruction of the ecological environment in some places; On the other hand, people are worried that the development of biofuels will crowd out cultivated land.
Because fossil fuel is the main part of primary energy in the world at present, its exploitation and combustion consumption are large, and its impact on the environment is also concerned.
The most typical impact of mining on the environment is coal mining, including the destruction of land, the destruction of villages and the impact on water resources. According to incomplete statistics, up to now, every time 1 10,000 tons of coal is mined, 0.2 hectares of farmland collapses, with an average annual collapse of 20,000 hectares. In China, more than 4.8 billion tons of coal are trapped under buildings, two thirds of which are trapped under villages.
In the plains of Shandong, Hebei, Henan, Anhui and Jiangsu provinces, there are 1 100 villages with more than one million villagers. The pollution of water resources by mining has a great impact on the ecological environment, with an average of 2 tons of sewage discharged per 1 ton of raw coal. What's more, in some areas, residents are short of water because of the serious pollution of water sources and rivers and lakes.
The impact of fossil fuels on the environment in the utilization process is mainly the pollution caused by various gases and solid wastes in the combustion process and the waste heat in the power generation process. Pollutants produced in the process of fossil fuels have two main impacts on the environment. First, global climate change. Carbon in fuel is converted into carbon dioxide and enters the atmosphere, which increases the concentration of carbon dioxide in the atmosphere, thus leading to the greenhouse effect and changing the global climate. Harm to ecological balance. Second, thermal pollution. The "waste heat" left by power generation in thermal power plants is discharged into rivers, lakes, atmosphere or oceans, which will cause thermal pollution in most cases. For example, when this waste hot water enters the water area, its temperature is 7 ~ 8℃ higher than that of the water area on average, which obviously changes the original ecological environment.