Also, would be 130.6 billion. Compare to the cost

Also, more people are worried about the potential dangers of nuclear energy. Many people are opposed to its use. They are shifting their opinions by many accidents. For example, the 2011 Fukushima Daiichi nuclear disaster in Japan makes many people consider whether the nuclear power is safe or not. With the development of the technology of nuclear power, most of the problems will be solved. Therefore, nuclear power has great potential for development. However, it will take a long time for the technology to mature. Before the technology becomes mature, whether nuclear power should be used is still unclear due to political and social pressure. In addition, nuclear power devices are large, and cannot be used on most of the transports. For transportation, fossil fuels are the main sources. For the moment, fossil fuels still dominate most of the market and alternative energies cannot replace the fossil fuels effectively in the short term.  
Other than fossil fuels, there are other energy sources such as renewable energy. (????)Although renewable energies can be used for generating electricity, they cannot be the main sources in the next few decades. For wind power and solar power are huge, the prices of them are high, the locations of establish went limited,  power production is influenced by the weather, and they cannot provide sustainable power. For the solar power, PV Solar Electricity will be considered first. However, the efficiencies are only approximately 13 percent and it will on work on day. Once meet cloudy day, it needs more storage efficiency. There are still other problems we need to consider. The cost of  PV module cost. The cost of a generating plant 87 million square meters in area would be 130.6 billion. Compare to the cost of fired plants, the PV Solar option would cost approximately 47 times the cost of the coal option (Ted). In addition, there is no doubt wind power is free and abundant, but in fact, it is less than what scientists might think. The primary problem is that it is intermittent. It means the electricity supply will be intermittent. For people and some devices, it is impossible. Also, once the wind is blowing too strongly(above about 50mph), turbines must be shut down to avoid damage (the limits to renewable energy). The location of the wind turbines is also a limit. It must locate in the areas that have Enough space and rich source of wind power.  Without improving the technology, renewable energies still cannot replace the fossil fuels completely.
Some scientists believe that biofuel could be a main energy source that can help humans become less dependent on fossil fuels. Biofuel is an energy-producing substance made from biological materials that cab be regrown every year. Thus, biofuels are a form of renewable energy (Funk). Liquid biofuels can be used in transportation and industry (Funk). However, it is not feasible. The capacity of the soil is limited. To cultivate bioenergy crops will intensify competition of land because some of biofuels are made from food. For example, soybeans and oil palm are used to make biodiesel. There will be no enough food for people to keep daily life. Also, regional suitability is one of the limits. The biofuel feedstock should be grown in appropriate region. Once it grows in other regions that are not appropriate, it will causes invasive ness or other more serious accidents. At the same time, some place are not suitable with growing biofuel crops ( In addition, growing a lot of biofuel crops will cause the decrease in forest area. People do not have enough lands to growing crops. Once large amount of biofuel crops are planted, it means the forest area will decrease. Therefore, biofuels can be a source of fuels, but they cannot replace the fossil fuels at all.
There is no doubt that electricity consumption will increase rapidly in the future. The EIA’s International Energy Outlook 2013 project shows that world energy consumption will grow by 56 percent between 210 to 2040, from 524 quadrillion British thermal units(Bfu) to 820 quadrillion Btu ( Today, fossil fuels are the biggest source of energy supply and predictably, fossil fuels still play an important role in electricity supply in 2040. In the future, it must be a variety of energy sources that make up the energy supply, but the most significant source is fossil fuels. Renewable energy and nuclear power are the world’s fastest-growing energy sources, each increasing 2.5 percent per year. However, fossil fuels will supply nearly 85 percent of world power use in 2040 (  In order to satisfying the demand of electricity consumption, it is impossible to skip fossil fuels. To avoid the shortage of the electricity, humans are continuing to expand all of energies sources that we can find including fossil fuels, nuclear power, solar power, wind power and biofuels to satisfy demands the use of fossil fuels because there is no single energy source can meet humans needs for energy. Therefore, fossil fuels alternative energies cannot replace fossil fuels because fossil fuels still are most effective energies nowadays.
It is clear that the global energy  problem is not a new problem. It has already existed for a long time and cannot be solved in a shot time. It is nothing wrong with putting future expectation on alternative energies. However, shifting from existing energy system to a new system require lots of time and technology is a big obstacle. At this time, it is necessary to maintain the existing energy supply. Alternative energies still have a lot of problems need to overcome before they can make contribute to the world’s energy supply.
With the limit of technology, disadvantages of alternative energies and the needs for energy, alternative energies cannot replace the fossil fuels effectively in a short term