In a certain period and place, under certain conditions, it has development value and can satisfy or improve the sum of the natural environmental factors of the current and future survival and living conditions of human beings, called natural resources, sometimes referred to as resources. The natural resources on the earth generally include climate resources, water resources, mineral resources, biological resources, energy and so on.
Energy is a natural resource that can be converted into a certain form of energy for human use under certain conditions, including all fuels, flowing water, sunlight, geothermal, wind, etc., through appropriate conversion methods, it can provide for human production and life. The energy needed. For example, fossil energy such as coal and petroleum can provide heat when burned, running water and wind can provide mechanical energy, and sunlight can be converted into heat or electricity.
Common natural energy sources include solid fuels, liquid fuels, gas fuels, nuclear energy, hydropower, solar energy, biomass energy, wind energy, ocean energy, and geothermal energy. Among them, natural fuels, mainly coal, oil, and natural gas, are collectively referred to as fossil fuels or fossil energy. These natural energy sources can also be converted into electric energy and other more convenient energy sources under certain conditions.
All kinds of energy have advantages and disadvantages. The pros and cons of energy can be evaluated and compared from the following aspects.
①. Energy flow density
Energy flow density refers to the power that can be obtained from a certain energy in a unit space or unit area. The energy flow density of fossil fuels and nuclear fuels is large, and the energy flow density of various renewable energy sources is generally relatively small. Renewable energy such as solar energy and wind energy with low energy flow density, small-scale application technology has been quite mature, and large-scale development needs to arrange a larger receiving area. If the energy flow density is too small, it is not conducive to development and utilization, because the economy is too poor.
②. Development cost and equipment cost
Fossil fuels and nuclear fuels, exploration, mining, processing, and transportation require a lot of manpower and material resources, and they also consume energy. For renewable energy such as solar and wind energy, the development cost is mainly a one-time investment in the development of energy. However, the cost of equipment for the use of renewable energy is relatively high. The initial investment per unit capacity is relatively small for power generation equipment using natural gas and oil, as well as hydropower equipment.
③. Possibility of storage and continuity of energy supply
The possibility of storage and the continuity of energy supply refer to whether energy can be continuously supplied, whether it can be provided immediately when it is needed, and whether it can be stored in large quantities when not in use. Based on the characteristics of energy sources, fossil fuels are relatively easy to store, and they are also convenient for continuous supply. Renewable energy sources such as solar energy and wind energy are not easy to store, and energy supply may also be volatile and intermittent.
④. Transportation costs and losses
The distribution of energy resources and the demand distribution of energy utilization are often inconsistent. From the place of energy development to the place of use, the transportation process itself also requires investment and energy consumption. The cost and loss of long-distance transportation will affect the use of energy. Solar energy, wind energy, and geothermal energy are difficult to transport. Fossil fuels can be transported, but the cost and energy consumption of transport must be considered.
⑤. Impact on the environment
Environmental issues have become a major global issue affecting human survival and future development. Committed to the use of energy, we must also consider its possible impact on the environment. The process of burning fossil fuels emits carbon dioxide (CO2) and other greenhouse gases, and even some toxic or corrosive substances, which have a greater impact on the environment. Nuclear fuel has problems with radioactive contamination and waste disposal. Renewable energy is mostly clean energy, which has little impact on the environment.
As a long-term use of energy, the reserves on the earth must be abundant enough. In addition, the geographical distribution of energy also affects its development and utilization. The reserves of non-renewable energy sources such as fossil fuels are limited, and they are always used up. Renewable energy such as solar energy and wind energy can be recycled and continuously supplemented. Even if the number of updates each year is limited, it will be endless in the long run.
⑦. Energy grade
Energy grade reflects the convenience of energy utilization. Generally speaking, the energy grade of secondary energy is higher than that of primary energy. Energy sources that can be directly converted into mechanical energy and electrical energy (such as water power and wind energy) are of higher grade than those that must be converted through the heat utilization process (such as fossil fuels).