The energy sources mentioned above, including fossil energy, nuclear energy and various renewable energy sources, are all "primary energy sources" and are obtained from nature. Through artificial processing, they can obtain different forms of product energy, which are called "secondary energy". If the various secondary energy sources are classified, they can be divided into two categories: fuel energy and non-fuel energy. The former includes gas, hydrogen, coke, gasoline and various fuel oils; the latter includes electricity, steam, hot water, and lasers. Secondary energy is usually high-quality energy. They either have high calorific value, clean combustion, high thermal efficiency, or are easy to transport and use, and are easily converted into other forms of energy, or they can meet different process requirements. Most of these secondary energy sources are familiar to everyone. This article will focus on electric energy.
- 1 Multifunctional electric energy
- 2 China's electrification
1 Multifunctional electric energy
Electric energy is a kind of high-quality secondary energy because it is very convenient to transport, control, convert and use without polluting the environment. Electric energy has been deeply rooted in every aspect of modern production and life, and has become a multi-functional energy source.
Electrification has become the basis of modern industrial and agricultural production. Electric energy is widely used in industrial and agricultural production, not only can improve labor productivity and product quality, improve labor conditions, save raw materials and fuel consumption, but also open up broad prospects for the application of new technologies. According to relevant statistics, countries with electricity consumption accounting for about 35% of total energy consumption have an energy consumption of 0.5 to 1.0 kilograms of standard coal per dollar of GDP (China's GDP), and countries with electricity consumption accounting for about 18% of total energy consumption , The energy consumption per dollar of GDP is as high as 2.0 kilograms of standard coal. In other words, the degree of electrification in production varies greatly, and the intensity of energy consumption varies greatly, and the backward energy use methods directly lead to high energy consumption.
Electrification has also become the material basis for improving the living standards and civilization of modern society. The widespread use of household appliances has greatly reduced housework and improved people's quality of life. The popularization of telephones and televisions has improved the social and cultural level. The general electrification of life can be divided into three stages: the first stage, electric energy is only used for lighting and small household appliances such as radios and televisions that consume less power; the second stage is developed to use more power-consuming refrigerators and microwave ovens , Electric rice cookers, electric frying pans, electric water heaters and air-conditioning equipment; the third stage is developed to the full electrification of electric heating and family life. We can test ourselves to what stage we have reached. But in general, most of the developed countries are currently or are transitioning to the third stage, their daily electricity consumption accounts for about 20% to 50% of the total electricity consumption, and the per capita annual electricity consumption is more than 1,000 kWh. ; Most developing countries are in the first stage, with low electricity consumption for daily life. The per capita annual electricity consumption is less than 100 kilowatt-hours. Electricity is restricted in the field of transportation, which requires portable fuel as energy source. However, electric power is not doing nothing in the field of transportation. The trams in cities and more and more railway transportation have been electrified, using electricity as power; electric vehicles are on the rise, and they also have broad development prospects.
The proportion of electricity consumption has become a sign of a country's level of development and industrialization. The energy used for power generation in developed countries accounts for more than 50% of primary energy consumption. Except for transportation, which uses petroleum as a power source, almost all other energy sources are converted into electricity for use. The widespread use of electric energy has made countries all over the world prioritize the development of the electric power industry. Electricity is so cute, but also in the diversity of its sources. Almost all primary energy can be easily converted into electrical energy. Especially for the collection of various renewable energy sources, such as hydropower, wind energy, solar energy, tidal energy, and ocean current energy, there is almost no more effective method than converting it into electrical energy. Fossil energy, especially coal, is also very convenient to convert into electricity. Although the efficiency of converting coal into electricity is only about 33%, the high efficiency of electricity use is enough to make up for it. Moreover, coal-fired power plants with large boilers facilitate the use of efficient smoke and dust removal facilities and desulfurization devices, which greatly reduces environmental pollution.
2 China's electrification
Electricity is a barometer of the national economy, and economic development is inseparable from the development of the electric power industry. China's economy continues to grow, and the development of the power industry has been at the forefront. In 2001, the scale of the power industry, both in terms of installed capacity and annual power generation, ranked second in the world, second only to the United States. In 2001, the total installed capacity reached 336 million kilowatts, and the total power generation was 1.47 trillion kilowatt-hours. But this amount still cannot meet the needs of economic development. According to the ratio of primary energy consumed by electricity production to the total primary energy consumption of the country, it is only about 30%, which is far behind the developed countries. The per capita electricity consumption is only more than 140 kilowatt-hours, and the degree of electrification is still very low. Therefore, the development of China's power industry still has a long way to go. It should be noted that the development of China's power industry still has the following problems: the power supply structure is not yet reasonable. The proportion of thermal power is large, the utilization rate of hydropower development is low, and nuclear power has just started. Take 2001 as an example, thermal power installed capacity accounted for 74.8% of the total installed capacity, hydropower accounted for 24.5%, and nuclear power only 0.7%. China's hydropower resources rank first in the world, but the level of development is far below the level of developed countries, and it has not been able to better play the role of different energy sources to achieve complementarity. Second, the level of technical equipment is low and the economy is poor. Although China's power generation technology has made great progress, the standard coal consumption for power supply (including power plants’ own electricity accounted for 6% and network line losses accounted for 7.5%) has dropped from 605 g/kWh in 1962 to 385 g/kWh in 2001 , A decrease of 37%, but there is still a large gap with the advanced indicators of developed countries, 50~70 g/kWh higher. The main reason is that China's technology and equipment are backward, such as large-capacity, high-parameter thermal power units that account for a small proportion of thermal power equipment, and the lower voltage levels of transmission lines. In addition, it is also related to the management level.
The third is serious environmental pollution. China's power industry is dominated by thermal power, and coal-fired power plants have an absolute advantage. Coupled with tight investment, they are insufficient in pollution control, and thermal power plants have a greater impact on the environment. As the country pays more attention to environmental protection and implements the scientific development concept, it is imperative to control power plant pollution in depth. Especially desulfurization has become an unavoidable task of the power industry.