Large-scale conversion from coal to gas is not suitable for China’s national conditions
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Large-scale conversion from coal to gas is not suitable for China’s national conditions. Author/Source: Tao Guangyuan, Executive Director of the Sino-German Center for Renewable Energy Cooperation. Date: 2017-01-11. Views: 7. Converting from coal to natural gas is referred to as the coal-to-gas conversion. In China, the initial aim of switching from coal to gas was to reduce air pollution caused by coal burning; additionally, it helps to cut carbon dioxide emissions, which is beneficial for global climate protection. The intention behind this measure is good. The conversion of large thermal power plants, cogeneration plants, or heating centers from coal to gas has been a topic of debate in China for several years. Recently, there has been a trend of large-scale expansion in the shift from coal to gas. To determine whether a policy is reasonable and good, there should be quantitative indicators for assessment. In the energy sector, there are four globally recognized main quantitative indicators: 1) Economic efficiency ； 2) Energy security ； 3) Environmental protection ； 4) Climate protection. Below, we will analyze the North China market as a relatively representative example. Looking at the first indicator – economic efficiency – the market price of natural gas is around 3 yuan per cubic meter (with subsidies for household use of natural gas). The calorific value of 1 cubic meter of natural gas is about 10 kilowatt-hours; based on this calorific value, the market price of natural gas is around 0.30 yuan per cubic meter. The price of coal with a calorific value of 5500 kcal is around 480 yuan per ton. Calculated on a per-kilowatt-hour basis, this amounts to 480 yuan/ton ÷ (5500 kcal/kg * 1.162 kWh/1000 kcal) ÷ 1000 kg/ton = 0.075 yuan/kWh. In other words, calculated based on the unit calorific value of primary energy, the price of natural gas is about 4 times that of coal. The maximum efficiency of gas-steam combined cycle power generation plus transmission and distribution is around 50%. The primary energy cost of gas-based power generation is 0.30 yuan/kWh ÷ 50% ≈ 0.6 yuan/kWh ； The maximum efficiency of coal-fired power generation and power transmission/distribution is around 40%, which is about 20% lower than that of gas-fired power. The primary energy cost of coal-based electricity is 0.075 yuan/kWh ÷ 40% ≈ 0.19 yuan/kWh. The primary energy cost of gas-powered power generation is about 0.40 yuan/kWh higher than that of coal-powered power generation. If cogeneration is used for heating, due to the high overall thermal efficiency of gas-based cogeneration, even though a large proportion of the energy produced is in the form of electricity, the heat output per unit of energy remains roughly equivalent to that of coal-fired power plants. Therefore, whether it is power generation or cogeneration has little impact on the cost difference between gas-fired and coal-fired power generation. According to the first criterion—economic efficiency—natural gas power generation is much more costly than coal power generation; the difference in the cost of primary energy per unit of electricity generated is approximately three times. Now let’s look at the second indicator – energy security. China has abundant coal resources, and it relies mainly on domestic production; imports account for about 5% of total consumption. With excess coal production capacity in the country, there is no concern regarding energy security. In China, both natural gas reserves and production per capita are quite low. Currently, about 30% of the total consumption is met through imports; this proportion is on the rise. A significant portion of these imports is transported across oceans via liquefied natural gas carriers. In December 2015, a shortage of natural gas supply occurred in parts of the Beijing-Tianjin-Hebei region due to the delayed arrival of ships carrying imported liquefied natural gas. This forced Beijing to reduce heating for non-residential buildings, causing indoor temperatures in many buildings to drop to around 14°C. The lack of gas for industrial use led to the shutdown of numerous enterprises that relied on natural gas in this area. To enhance the security of natural gas supply, many countries maintain reserves of natural gas; Germany, for example, has reserves that are sufficient to cover three months’ worth of demand, while the Beijing-Tianjin-Hebei region has very limited such reserves, leading to gas shortages during winter. Building capacity for storing liquefied natural gas requires substantial investment. Clearly, in terms of the second indicator—energy security—the energy security of natural gas is much lower than that of coal. Regarding the third indicator—environmental protection—the main environmental issue associated with coal-fired power generation is air pollution caused by the combustion exhaust gases. However, treating coal-fired flue gas in accordance with the emission standards for gas-fired flue gas is no longer a technical issue today, and the cost will not exceed 0.10 yuan/kWh. Due to the high combustion temperatures in gas turbines, a large amount of nitrogen oxides are generated during fuel combustion. The costs associated with nitrogen oxide removal are high, and such removal processes can easily release ammonia into the atmosphere. Of course, the construction cost per unit capacity for coal-fired power plants is slightly higher than that for gas-fired ones. Even when adding the higher environmental costs and construction costs per unit of power generation capacity associated with coal compared to natural gas—in order to achieve the same environmental impact as natural gas—the cost of generating electricity from natural gas remains at least 0.20 yuan/kWh higher than that of coal-fired power generation. When using gas to replace coal in power generation or combined heat and power production, approximately 60% less carbon dioxide is emitted per kilowatt-hour of electricity generated, which means an emission reduction of around 0.47 kilograms of carbon dioxide per kilowatt-hour. Assuming that the cost of gas-based power generation remains at least 0.20 yuan/kilowatt-hour higher than that of coal-based power generation, the cost of reducing carbon dioxide emissions by using gas instead of coal is equal to 0.2 yuan/kilowatt-hour ÷ 0.47 kilograms/kilowatt-hour × 1000 kilograms/ton = 425 yuan/ton. China’s subsidy for wind power generation is around 0.2 yuan per kilowatt-hour. Since wind power generates almost no carbon dioxide, the cost of reducing carbon dioxide emissions through wind power is approximately 0.2 yuan/kWh ÷ 0.78 kg/kWh × 1000 kg/ton = 256 yuan/ton. In other words, the cost of reducing carbon dioxide emissions by switching from coal to gas is about 66% higher than that of using wind power. Currently, the trading price of carbon dioxide on China’s carbon trading market is only 20 to 50 yuan per ton. If carbon trading is used to replace coal-to-gas conversion in order to reduce CO2 emissions, the cost would be only 1/20 to 1/8 of that associated with coal-to-gas conversion. Of course, this price is far too low and not conducive to promoting carbon dioxide emission reductions; it should be increased significantly in the future. It is reported that **Jiang Zhaoli, deputy director of the Climate Department of the National Development and Reform Commission, believes that a reasonable trading price for carbon dioxide in China’s carbon trading market in the future should be between 200 and 300 yuan per ton. Even at this price, which is generally considered difficult to achieve, the carbon dioxide emission reduction cost of switching from coal to gas remains 40% to 100% higher. It should be noted that due to the rapid development of coal mining capacity in our country, coupled with a significant decline in coal demand in recent years, coal prices have dropped sharply. As a result, many coal companies have suffered heavy losses, which has led to a reduction in employment numbers. In this context, a large-scale shift from coal to gas would deal a further blow to the coal mining industry. Coal is an industry on the decline; from now on, China’s coal production is likely to keep falling over the next few decades. However, if the decline is too rapid over a period of time, it will also result in significant economic losses for the coal industry, increase financial risks, and create substantial employment pressures. China’s increase in natural gas imports boosts employment and income in natural gas-producing countries, while reducing employment in China’s coal industry and lowering its economic efficiency. In summary, large-scale conversion from coal to gas: the economic benefits are very poor ； Energy security is very poor ； The improvement in environmental benefits can be achieved through the modification of flue gases from coal-fired power generation ； The cost of reducing carbon dioxide emissions is too high; it is far inferior to coal combustion and many other methods for cutting carbon dioxide emissions. Therefore, it is clearly unsuitable for China’s national conditions to widely replace coal with natural gas in thermal power plants or combined heat and power plants. China currently has around 250 million kilowatts of cogeneration units, most of which are coal-fired cogeneration units. If 100 million kilowatts of coal-fired cogeneration units are replaced with gas-fired cogeneration units, and assuming that each kilowatt of generating capacity produces 4,000 kWh of electricity per year, then 400 billion kWh of electricity would be generated annually. With an additional cost of 0.20 yuan per kWh for electricity generation, the total additional cost would amount to 80 billion yuan per year! In summary, to achieve the same environmental and climate protection benefits as switching from coal to gas, it is much more economical than using gas-powered power generation, and the energy supply is also much safer, thanks to cleaner treatment of flue gases from coal-fired power plants/cogeneration plants, along with emission reduction measures that incur low costs. Even in developed countries, coal-fired power plants and cogeneration plants still play a very important role. For example, in Germany’s Ruhr industrial region, which covers an area of less than 10,000 square kilometers, there are coal-fired power plants and cogeneration plants with a capacity of around 10 million kilowatts ； The largest coal-fired combined heat and power plant in Berlin, the German capital, with a capacity of one million kilowatts, is located only about 10 kilometers away from the city center. smoothly
Everything should be done step by step; one can’t just do whatever comes to mind. Beijing is the capital, so it’s normal to do that
Think in the long term – when an energy crisis occurs, you’ll still have to use coal. Moreover, burning coal generates waste residues; transporting it is not as convenient as with natural gas, and you need to build storage facilities for coal. Its use is also less convenient compared to natural gas. You need to consider all these aspects; your economic considerations are not comprehensive enough
I fully agree with the views presented in the original poster’s information. China’s push to replace coal with gas in many cities is, in fact, a highly unscientific and uneconomical approach. The cost of natural gas is very high; this burden placed on the general populace is like a knife cutting into their flesh. Adopting coal-fired thermal power generation and ensuring proper desulfurization and denitrification is what suits China’s national conditions.
But I’ve already enforced this; all of the company’s boilers must be switched to natural gas
I don’t have that situation; we use district heating instead. It’s easier to manage, and it facilitates desulfurization and denitrification. The boilers owned by enterprises have been shut down
Opinions on this vary from person to person. The transition from coal to gas is a trend towards cleaner energy sources. This process is taking place not only in China but worldwide. The more developed an economy is, the greater the demand for clean energy becomes, and thus the stronger the impetus for switching from coal to gas
It can’t be said that the “expert” who wrote this article is wrong, but it’s obvious that their reasoning is rather chaotic. First of all, **or someone said that all power generation should be switched from coal to natural gas. It is well known that large coal-fired power plants can achieve clean emissions that meet the required standards; **no one has ever said that the proportion of coal-fired power plants should be reduced to zero in years to come! Therefore, the shift from coal to gas applies mainly not to large power plants, but to small boilers that are inefficient and produce a lot of pollution. Natural gas has been desulfurized and dehydrated; when used for heating or domestic purposes, there are no issues with sulfides. As for nitrogen oxides, their levels are similar to those produced by burning coal – higher combustion temperatures result in higher levels of nitrogen oxides, and these still need to be removed. Nevertheless, this is certainly better than using small coal-fired boilers, as gases are easier to mix, making it simpler to achieve low-nitrogen combustion compared to using coal. Of course, the author mentioned one problem: high costs. This is the most practical issue. But there’s one thing that confuses him: why are natural gas prices so high, four times those of coal? Could they not be lower? Is natural gas extraction determined solely by enterprises? Can companies that purchase pipelines from external sources do anything about it? Can companies involved in LNG procurement and storage exert any control? I’ve heard Taiwanese people say, “Why produce hydrogen from coal? I’d use LNG instead, even though it’s more expensive.” Do you know how much I paid for it myself? ”And as for high prices, the cost of liquefied gas is nothing compared to housing prices in major cities; it all depends on the guidance provided by XX. No one wants to live in a foggy environment, after all – we need to learn from more advanced practices in every aspect, not just when it comes to housing prices. Looking at the development processes in neighboring Asian regions, an increasing share of natural gas in energy consumption is a very evident trend; in 2014, Japan used 123.9 billion cubic meters of natural gas, South Korea used 50.8 billion cubic meters, and Taiwan used 17.7 billion cubic meters. In 2015, China produced 134.5 billion cubic meters domestically and purchased 62.1 billion cubic meters, with a per capita level that is far lower than that of these relatively developed regions. Of course, in East Asia, we don’t compare ourselves with XX; they have psychological weapons. Next, there’s something to complain about: “In December 2015, due to the delayed arrival of ships carrying imported liquefied natural gas, there was a shortage of natural gas supply in some areas of Beijing, Tianjin, and Hebei. This forced Beijing to reduce heating for non-residential buildings, resulting in indoor temperatures dropping to around 14°C.” What does that mean? In our Jianghuai region, during winter, the indoor temperature on the top floors drops to 3°C. A 2-kilowatt electric heater, when used in a 10-square-meter space for three hours, only manages to raise the temperature to 9°C (and perhaps the power output of such cheap heaters is not accurate). There have been three or four instances of indoor icing in the past fifteen years. Once, the water in the toilet froze for 23 days (there was nothing I could do; at the same time, the water pipes froze as well, causing a water outage; everyone had already left). In my neighbor’s house, there was no water supply for 15 days. Once, I set off from Tianjin and traveled to Dalian as well as the capitals of the three northeastern provinces. I couldn’t stay in any of those shopping malls – it was hotter there than in a bathhouse. The salespeople were wearing short-sleeved shirts that even revealed their navels, while it was minus 30 degrees outside. Another time, when I went to Xinjiang, I had to go shirtless in the hotel. Shouldn’t it be said that “the pitiable X must have detestable aspects”? Finally, the author compares wind power generation with carbon emissions – that’s completely unnecessary. As long as carbon-based materials are used as fuel, CO2 will be emitted, but people cannot reduce their demand; therefore, the only options are to improve efficiency or change the type of raw materials used. Everyone knows this issue – so why keep talking about it? It’s the carbon tax again; he thought this tax wouldn’t fall on him in the end, but once its collection starts, no one can avoid it. Of course, in the end there was finally a sentence like, “Developed **” – right, there are several good teachers; just study hard and that’s it! What’s the point of studying it over and over again? People must have already thought of it decades ago.
This is also an inevitable outcome. Natural gas is clean to use.