Development and contribution of natural gas industry under China's carbon neutrality goal

2.3.2 Imported Pipeline Gas and liquefied Natural Gas (LNG)

In 2020, China's import volume of natural gas will reach 10 166×104 t (about 1 400×108 m3), of which the import volume of LNG will be 6 739.45×104 t (about 930×108 m3), and the import volume of pipeline gas will be 3 453.11×104 t (about 480×108 m3). Total imports increased by 5.3% year on year, of which LNG imports increased by 11.4% from 2019 and pipeline gas imports decreased by 4.9%[20-22]. China has completed the construction of Central Asia, China-Myanmar and China-Russia natural gas pipelines, with a total designed annual gas transmission capacity of more than 1 100×108 m3. Meanwhile, by the end of 2020, China has completed 22 LNG receiving stations, with an annual receiving capacity of 9 045×104 t. At present, the capacity of coastal LNG receiving stations under construction exceeds 2,000 ×104 t/a[20], which will be put into operation this year and next. At present, China's imported pipeline gas mainly comes from Central Asia and Russia, and the main sources of imported LNG are Australia and Qatar. In 2020, China's LNG import from the United States increased significantly, reaching 320.44 ×104 t, while in 2019, the LNG import from the United States was only 27.6×104 t[22-23]. On January 15, 2020, with the signing of economic and trade agreements between China and the United States, China will also expand imports of energy products from the United States in the future. On March 27, 2020, China and Iran officially signed a 25-year cooperation agreement to strengthen all-round cooperation between the two countries in the fields of economy, trade, energy and security, which represents a more diversified choice of natural gas import sources for China.

2.3.3 Coal-to-synthetic Natural Gas (SNG)

Coal has long been the main source of energy in China, mainly used for power generation and heating. With the goal of carbon neutrality, the use of coal will gradually decline, and it is expected that by 2060, coal will be completely withdrawn from the power generation industry, so there is an urgent need to expand the use of coal and promote the clean use of coal. As a kind of synthetic natural gas, coal-to-gas can not only enrich the consumption of coal, but also alleviate the tight situation of domestic natural gas supply to a certain extent. Especially for the provinces with good coal resource endowment, coal-to-gas is the key and important development direction for coal to get rid of the single fuel attribute and realize the efficient and clean utilization of coal. Different from oil and gas resources, China has abundant coal reserves and large resources, with proven reserves of about 10 000×108 t and proven recoverable reserves of 1 145×108 t[24]. According to the current standard of producing about 300 m3 of natural gas from 1 t of raw coal, the output of coal-to-gas can exceed 30 000×108 m3. In 2019, the national coal-to-gas production has reached 36.8×108 m3 [22], and there is huge potential for coal-to-gas production in the future, especially in coal-rich areas.

2.3.4 Synthetic (man-made) natural gas

Using "electricity to gas +CCUS" to achieve artificial natural gas, while completing the conversion and storage of renewable energy. Green hydrogen (H2) and oxygen (O2) are prepared through renewable electricity electrolysis technology. Hydrogen can be used to synthesize methane, and oxygen can be used to enrich oxygen for power generation. At the same time, the use of underground space such as underground depleted oil and gas reservoirs, injection of industrial by-product impurities hydrogen and carbon dioxide, through microbial catalysis and other ways to produce biomethanes, to complete the large-scale conversion of renewable energy into methane and other clean energy. As a promising CCUS and energy storage technology, this technology has completed preliminary research and laboratory tests in Germany, and has been carried out field tests, with wide application prospects.

2.3.5 Natural gas hydrate

Gas hydrate, also known as combustible ice, is a kind of ice-like crystalline substance formed under high pressure and low temperature. The main components are methane and water molecules. It is widely distributed in deep sea or land permafrost. Research shows that the decomposition of natural gas hydrate per cubic meter can produce 160 times the volume of methane, and its combustion product is only water and a small amount of carbon dioxide, which is a new type of high calorific value clean energy. The investigation shows that the natural gas hydrate in China is mainly distributed in the South China Sea and the Qinghai-Tibet Plateau, with a potential resource of 12.15×1013 m3 and great potential for development. In May 2017 and March 2020, China has successfully conducted two test mining of natural gas hydrate in the Shenhu area of the South China Sea, of which the cumulative gas production of the second round of test production exceeded 86×104 m3 [25-26]. Although the development of natural gas hydrate is at an early stage and full of challenges, its advantages of cleanliness, high energy, wide distribution and large reserves provide a new development direction for China's energy strategy, and it is an important energy technology reserve.