Coal power is still irreplaceable in China

China's coal power is currently in a very awkward position. In terms of energy conservation, coal and electricity are best combined with heat and power, and the energy utilization rate can be increased to 80%. In terms of coal saving, it is better to build a single unit with a million kilowatts of ultra-supercritical units. However, in terms of peak regulation, frequency regulation and reserve capacity for hydropower, nuclear power, wind power and photovoltaic power generation, the minimum technical output of coal power should be reduced to 10% or even lower, the large coal-electric unit undertakes the deep peak adjustment and frequency modulation unit, and the efficiency of the ultra-supercritical unit is immediately reduced to subcritical.

China's gas and electricity are also in a very awkward position. In terms of energy conservation, gas and electricity are best to engage in distributed energy systems, distributed cogeneration of heat and power, and the energy utilization rate can reach 80%. In terms of energy saving benefits, gas and electricity are best built into a gas-steam combined cycle power plant. However, in terms of peak regulation, frequency regulation and reserve capacity for hydropower, nuclear power, wind power and photovoltaic power generation, gas and electricity are best built into a single-cycle gas turbine power plant, although the power generation efficiency is not very high, but as hydropower, nuclear power, wind power, photovoltaic power generation peak, frequency modulation, backup power supply is handy.

2 Classification of thermal power in China

China classifies thermal power into coal power, gas power, oil power and others (including ① residual temperature, residual gas and residual pressure power generation, ② waste incineration power generation, ③ straw, bagasse and forest wood power generation). Among them, coal power, gas power and oil power should be classified as fossil energy power generation. Coal, oil and electricity is also known as high carbon, high pollution energy power generation, gas power is also known as low carbon clean energy power generation. The other three types of power generation can be classified as non-fossil energy generation. It can be seen from this classification that gas power and the other three types of power generation should be advocated. Oil power is very small and negligible. Only coal power is to be phased out. In 2015, the 8th issue of "energy" magazine proposed that the downward thermal power should be changed to the downward coal power. But whether coal power should go down is up for debate. China's thermal power classification is very clear, foreign countries have not divided thermal power so clearly. According to the statistics of 20 major power countries, only the thermal power generation is divided into coal power, oil power, gas power and biomass power generation for statistics. Although it is not as detailed as China's, it is roughly clear. However, the installed capacity of thermal power cannot be clearly distinguished, because the fuel used includes single fuel (such as solid, liquid, gas and biomass) and mixed fuel (such as solid/liquid, solid/natural gas, liquid/natural gas, and solid/liquid/gas). The power generation can be calculated according to the amount of solid, liquid and gas used, however, it is difficult to calculate the installed capacity of solid, liquid and gas with the installed capacity of mixed fuel power generation. Therefore, in the electricity statistics of the United Nations, the electricity of the 20 countries in the world is only the total installed capacity of thermal power, the total power generation of thermal power and the classified power generation of coal power, oil power, gas power and biomass power generation, and accordingly only the utilization hours of thermal power equipment. there is no utilization hours of coal power, oil power, gas power and biomass power generation equipment.

3 Power structure of major power countries

As mentioned earlier, electricity is a very complex complex, including the dirtiest power source-coal power, clean fossil energy (natural gas) power generation, and new energy power such as waste incineration power generation and biomass energy. Coal power is to control the development, gas power and new energy power generation is to encourage the development. Generally speaking, new energy power generation such as wind power and solar photovoltaic is intermittent, random and unstable, and requires flexible power sources to cooperate with operation, including natural gas power generation, pumped storage power stations, and large and medium-sized hydropower stations with good regulation performance. when flexible power sources are insufficient, coal-fired power plants can also be used as a matching power source for new energy, and of course there are energy storage facilities. What power supply is used as a flexible power supply for new energy power generation depends on the power supply structure of each country.

There are also the following reasons for clarifying the structure of thermal power: ① The efficiency of coal-fired power generation is low, while the efficiency of gas-fired power generation is high. In developed countries, the proportion of coal-fired power is small, and the proportion of gas-fired power is large. All kinds of indicators use thermal power, so it is difficult to distinguish which energy has high power efficiency. In particular, China is mainly coal power, gas power is very few, the so-called thermal power economic indicators, in fact, coal power indicators, China's most advanced coal power can not compare with backward gas power, so it is best to classify thermal power clearly, easy to compare. The role of coal power and gas power in thermal power plants is different, the former is used to bear the base load and waist load, the latter is used for peak regulation and frequency modulation. In the United States, the utilization hours of the two equipment are more than double. For example, in the past 10 years, the utilization hours of coal and electricity equipment in the United States are as high as 6000h instead of the average utilization hours of thermal power of 3000~4000h. The reason is that the utilization hours of coal and electricity are calculated in a unified way. After the utilization hours of coal and electricity are averaged by gas and electricity, the average utilization hours of thermal power is lower. It seems that the composition of thermal power should be clarified, and coal power, gas power and new energy power generation should be counted separately. However, the gas and electricity in the United States have only gone up in the last 10 years or so. According to statistics, in 1990, the proportion of coal and electricity in the United States was 53.07 per cent, while that of gas and electricity was only 11.92 per cent. In 2000, the proportion of coal and electricity was 52.9 per cent and that of gas and electricity was 15.76 per cent, with little change. It was only after the shale gas revolution that the U.S. replaced coal with shale gas, and it was only in 2012 that U.S. coal power fell to 38.31 percent and gas power rose to 29.83 percent, a big change. Therefore, it is also a matter of recent years for U.S. coal and electricity to bear the base load and waist load, while gas and electricity to bear the peak load and frequency modulation. Without gas and electricity, coal and electricity have to bear the peak load, waist load and base load, just like the current situation in China.

The structure of thermal power in the world is different, and the power supply structure is very different. In the power structure of the 20 major power countries (see table 1), some countries are dominated by coal power, such as South Africa with 93.77 per cent, Poland with 84.33 per cent, China with 70.45 per cent, Australia with 69.70 per cent and India with 67.94 per cent. Some countries have a relatively large proportion of gas and electricity, with only Mexico (52.22 per cent) accounting for more than 50 per cent of total power generation; three countries have more than 40 per cent of gas and electricity, 41.2 per cent in Japan, 49.31 per cent in Russia and 46.15 per cent in Italy. Some countries are dominated by hydropower, such as Norway, which accounts for 96.63 per cent, Canada for 58.86 per cent and Brazil for 80.60 per cent. The only country that dominates nuclear power is France, accounting for 76.65 percent.

Coal power is still irreplaceable in China

Countries in Europe and the United States develop new energy power. Spain, Italy, the United Kingdom, and the United States can use gas power as flexible peak shaving, frequency modulation, and backup power sources. For example, Germany has a small number of gas power, and the development of new energy power has increased, and it has to rely on coal power. Peak shaving, frequency modulation and backup. The situation in China is similar to that in Germany, where there is very little gas and electricity, accounting for only 2.1 per cent, and hydropower and new energy electricity are regulated mainly by coal and electricity.

4 China's coal power development prospects

Electricity Demand and the Role of Coal Power in 4.1 China

China's electricity demand has grown more slowly in recent years, rising only 3.8 per cent in 2014, 1.3 per cent in the first half of 2015 and 0.8 per cent in January-July. The demand for electricity is growing slowly, and all new electricity installations have to generate electricity and generate income, so the contradiction is very prominent. From January to July 2015, power generation from power plants above designated size nationwide increased by only 0.4 percent, hydropower increased by 9.6 percent year-on-year, nuclear power increased by 3.5 percent year-on-year, and coal power decreased by 3 percent year-on-year. From January to July 2015, the cumulative average utilization hours of power generation equipment nationwide was 2293h, down 188h from the same period last year. Among them, hydropower was 1911h, an increase of 59h over the same period last year. Nuclear power 4183h, an increase of 114h over the same period last year; Wind power 1107h, down 10h from the same period last year; Thermal power 2535h, down 259h from the same period last year. It can be seen from here that when the demand for electricity is weak and the supply of electricity exceeds demand, we must first protect non-fossil energy power generation, let hydropower, nuclear power, wind power, and solar photovoltaic power generation give priority to power generation, and minimize water, wind, and light abandonment., Nuclear power generation increased significantly compared with the previous year, the utilization hours of hydropower and nuclear power generation equipment also increased, while the utilization hours of thermal power equipment decreased significantly. There are few gas-fired power plants in China and they are just developing. As the price of natural gas is several times that of coal, the on-line electricity price of gas and electricity in China is 0.8 yuan/kWh, which is more than double that of coal and electricity. The replacement of coal and electricity by gas and electricity is not smooth. Therefore, the utilization hours of thermal power in China have decreased significantly.

There are two reasons for the decline in the utilization hours of coal power equipment: first, coal power is used as a supporting power source for hydropower, nuclear power, wind power and solar photovoltaic power generation, and as a peak shaving, frequency modulation and backup power source for non-fossil energy power, so the utilization hours of equipment are reduced. In China, coal power is the best and cheapest matching power supply. It is said that using storage batteries as matching power supplies requires an investment of 40 thousands or 50 thousands yuan per kilowatt, which is 10 times that of coal power. The life span is only 5 years, which is 1/6 of that of coal and electricity. The loss is 30%, and there is no loss of coal and electricity.

Others, such as hydrogen energy storage and compressed air energy storage, have problems such as large investment, short life and large energy loss. It is now believed that the most mature pumped storage energy storage is originally low-valley energy storage and peak power generation, which can achieve the best positive benefits. However, when photovoltaic power generation prevails, pumped storage peak power generation is difficult to achieve, only thermal power cooperation is the most appropriate. China's coal power has created the most favorable conditions for the development of China's non-fossil energy power. Second, coal power as a motor power source, when the demand for electricity growth is slow, non-fossil energy growth is rapid, the power system can not be absorbed, coal power to give way to non-fossil energy power generation, coal power generation and utilization hours will drop sharply, and non-fossil energy power at any time there is no problem of production reduction. So when electricity demand is weak, the biggest impact is coal power. When the demand for electricity is weak, people ignore the role of coal power in the power system for non-fossil energy power, and all hope to reduce coal power, but if coal power does not match, then hydropower abandons water, wind power abandons wind, and photovoltaic abandons light will be more serious.

4.2 electricity demand forecasting

Under the above circumstances, it is hoped that power demand forecasting will lead power investment, but power demand forecasting is an extremely difficult thing. Some people once predicted that electricity demand will increase by 4% to 6% from 2014 to 2015, but in fact it will only increase by 3.8 in 2014. In 2015, electricity demand grew more slowly, rising 2.5 percent from January to February, 0.8 percent from January to March, 0.9 percent from January to April, and 1.1 percent from January to May, reaching 1.3 percent from January to June. Judging from the trend in the first half of 2015, it is thought that the demand for electricity will continue to rise in the second half of the year, reaching about 3% throughout the year. As a result, it will only increase by 0.08 from January to July.

Even the first half of the year cannot predict the second half of the year, so it is even more difficult to predict 10 or 20 years. Everyone is more cautious when the growth rate is weak in demand. If some units predict that the highest growth rate of China's electricity demand in the future will be more than 4%, less than 5%. According to research by relevant departments, the growth rate of electricity demand will gradually slow down from now to 2030, and the average growth rate will slow to 2.7 from 2020 to 2030. The direct consequence of changes in the market supply and demand situation is the decline in the number of hours of thermal power generation. Judging from the recent economic crises, such forecasts are unreliable and far from reality. China's electricity consumption grew by 4.8 per cent in the year of the East Asian economic crisis in 1997, compared with 2.8 per cent in 1998. At that time, China's fifteen power forecastPlanThe annual growth of power generation is 5.04 per cent, the annual growth of installed capacity is 4.08 per cent, and 15 per cent.PlanThe actual implementation results in an annual growth of 121.7 per cent in power generation and 10.1 per cent in installed capacity, more than double the actual growth plan. In 2008, the U.S. subprime mortgage crisis spread to China. In 2008, electricity consumption increased by only 5.6 percent. After 2008, annual power generation increased by 10.92 percent on average, and installed capacity increased by 10.96 percent on average. The growth rate recovered quickly. Although it is in a different historical period from the 15th and 12th five-year plans, it is impossible to have such a big difference. It seems that it is very difficult to determine the new power capacity based on the average supply and demand situation and guide the power investment based on the demand signal.

Electricity demand forecasting is better under planned economy conditions, but it is difficult to forecast under market economy conditions, especially at the turning point of the economy, such as the Southeast Asian financial crisis in 1997, the subprime mortgage crisis in the United States in 2008, and the new economic normal that began in 2014. If in accordance with the "Several Opinions on Further Deepening the Reform of the Electric Power System (Zhongfa [2015] No. 9)"Design, control the middle, let go of the two ends, large, small, and medium users all purchase electricity from power plants. Through the user's long-term contract, you can understand the user's long-term demand for electricity, and you can also know how many power plants should be built in the long-term. What kind of power plant, including

How many coal and gas power plants to build. However, since Zhongfa [2015] No. 9 has just been issued, the system relying on the power market mechanism has not yet been established, and users have not yet signed long-term contracts with power plants.

4.3 the Bottleneck of Developing Non-fossil Energy in China

In order to develop non-fossil energy power, gas power and coal power are still necessary to exist. Gas power and coal power will exist as peak shaving, frequency modulation and backup power sources for non-fossil energy power for a long period of time. Since they are necessary to exist, they should be provided with the conditions for their survival, that is, to assign thermal power to undertake the tasks of peak shaving, frequency modulation and backup and to provide corresponding benefits, that is, thermal power should be reasonably compensated for the reduction in equipment utilization hours due to the supporting role of non-fossil energy. This is what Zhongfa [2015] No. 9 proposes: the establishment of a new mechanism for the sharing of ancillary services. To adapt to the new demand for auxiliary services such as peak regulation, frequency regulation, voltage regulation and user interruptable load, and improve the new assessment mechanism and compensation mechanism for grid-connected and shared enterprise auxiliary services. According to the reliability and service quality of the power grid, and according to the principle of who benefits and who bears, the sharing mechanism of auxiliary services with user participation is established.

Although it is difficult to forecast power demand, the proportional relationship of power construction can be predicted, and China's power industry is characterized by a large proportion of thermal power generation and a large proportion of small thermal power without adjustment capacity in thermal power. The regulation performance of large and medium-sized hydropower stations is poor, and hydropower is the most dependent on coal power in China's non-fossil energy power. In recent years, China's new energy power and nuclear power have developed vigorously, which also puts forward high requirements for coal power. Natural gas power generation Because natural gas is more expensive than coal, the on-grid price of natural gas power generation is more than twice as expensive as coal power. Although natural gas power generation is more mobile than coal power, it lacks economic competitiveness, so natural gas power generation has been slow to replace coal power. In addition, coal power and natural gas power generation have the task of developing cogeneration and cogeneration, so coal power and gas power can really be used as supporting power sources for non-fossil energy power. For example, coal power claimed to have a power generation capacity of 0.82 billion kW in 2014, excluding 0.25 billion kW of thermal power units, 600000-1 million kW of supercritical and ultra-supercritical large units are used for basic power generation of about 0.35 billion kW, and only 0.22 billion kW can be used as supporting power supply. Natural gas power generation 0.055 billion kW, excluding 0.02 billion kW of distributed energy system, can be used for supporting power supply is 0.035 billion kW; In addition, there is pumped storage for supporting power supply. 0.02 billion kW. The total of the above 3 items is 0.275 billion kW. However, the required supporting power sources are regular hydropower 0.28 billion kW, nuclear power 0.02 billion kW, wind power 0.095 billion kW and solar photovoltaic power generation 0.026 billion kW, totaling 0.421 billion kW. According to the calculation that each kilowatt of non-fossil energy power is equipped with a matching power supply of 1kW, non-fossil energy power needs to be equipped with a matching power supply of 0.421 billion kW. The above three can provide a matching power supply of 0.275 billion kW in total, and the reduction of the two still lacks a flexible matching power supply of 0.146 billion kW. The matching problem of power transmission and transformation engineering department has not been considered here. This is the root cause of China's current abandonment of wind, water and light. Therefore, although the power demand cannot be accurately predicted, it is possible to measure whether the flexible supporting power supply can keep up with the development of non-fossil energy power. If coal power, gas power and pumped storage are not added, the development of non-fossil energy power should be properly controlled.

5 The irreplaceability of coal power in China

There are various understandings of the energy supply revolution, and General Secretary Xi Jinping's interpretation of promoting the energy supply revolution is to promote the energy supply revolution and establish a diversified supply system. Based on domestic diversified supply insuranceSecurityVigorously promote the clean and efficient use of coal, focus on the development of non-coal energy, form a coal, oil, gas, nuclear, new energy, renewable energy multi-wheel drive energy supply system, and simultaneously strengthen the construction of energy transmission and distribution networks and reserve facilities. General Secretary Xi advocated the establishment of a diversified supply system in the energy sector, and did not mean to exclude coal. Coal is a kind of energy based on domestic energy in China's energy field, and it is also an important part of diversified energy supply, which can ensure domestic energySecurityThe important role of energy prices. On the one hand, General Secretary Xi proposed to vigorously promote the clean and efficient use of coal, on the other hand, he should focus on the development of non-coal energy. The meaning of non-coal energy should be broader than non-fossil energy, and it should include the clean and efficient use of oil and natural gas. General Secretary Xi Jinping's assertion is based on China's latest electricityTechnologybased on achievements.

China's coal power is closely related to China's energy revolution. China is a country dominated by coal, and the corresponding power generation energy is also dominated by coal. 60% of China's installed power generation capacity is coal power, and 70% of the power generation is coal power. If coal power is really replaced by other power sources like developed countries, it is a very important thing. China's coal power industry is determined to solve the pollution problem of coal-fired power generation. China has done what developed countries have not done. Through efforts in coal power desulfurization, dehydrogenation, dust removal, etc., China has achieved near-zero and ultra-low emissions of pollutants, which can be less than that of natural gas power generation. Now the coal power industry is working hard to solve the problem of CO2 emission reduction. Therefore, what General Secretary Xi Jinping said to vigorously promote the clean and efficient use of coal is to make coal power generation as clean and efficient as natural gas power generation, as clean and efficient as wind energy and solar energy, and to ensure the country's energy.Securityand access to cheap energy, which is exactly the right strategic decision.

On the other hand, the scale of coal-fired power is very large, with an installed capacity of 0.825 billion kW and an annual power generation of 3.9 trillion kWh at the end of 2014. It is difficult to replace it with non-fossil energy in a short period of time. China's thermal power has developed 0.3 billion kW. In terms of the amount of resources that can be developed, it can only develop 0.1 billion kW at most. China's nuclear power experts believe that China's nuclear power installed capacity should be controlled at about 0.15 billion kW, not more than 0.2 billion kW at most, and the pace of construction should be firmly grasped. This means that nuclear power will not exceed 0.2 billion kW at most, so the two resources with better conditions in non-fossil energy power are limited and cannot replace coal power. Due to the intermittent and random nature of wind power and solar photovoltaic power generation, wind power and solar photovoltaic power generation still have to rely on coal power and gas power as peak shaving, frequency modulation and backup power supply before the energy storage problem is solved, so it is impossible to completely replace coal power. Gas power and coal power will still be necessary for a long time to come, and even coal power should be developed.

China's coal power has achieved near-zero emissions, ultra-low emissions, supercritical, ultra-supercritical units developed rapidly, so that coal consumption decreased year after year. China's coal power to non-fossil energy development to provide support services for energy.SecurityPowerSecurityIt provides a guarantee for maintaining the lowest electricity price in the world. The clean and efficient use of coal in China has made the low-carbon and green development of China's energy a reality. China's coal power can achieve environmental protection,SecurityCheap, the best effect of the three at the same time.