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

In the low-speed scenario, the world will be affected by the COVID-19 epidemic for a long time, international relations will remain tense, trade frictions will not improve significantly, and the Chinese economy will maintain steady growth with more reliance on the domestic cycle. It is expected that the average annual economic growth rate in the period from 2021 to 2060 will remain at about 2.5%, with an average annual economic growth rate of 4.5% in the first 10 years and 1.83% in the next 30 years. In the short term, the elasticity coefficient of fixed base energy consumption fluctuates less, and is still predicted to be 0.18 in 2030. Subject to the slowdown of economic growth, the elasticity coefficient is predicted to be 0.10 in 2060, which is slightly higher than the base scenario. Under the influence of various factors, China's total energy consumption will grow steadily in the short term. In 2030, the total primary energy consumption will reach 55.14×108 t, and then enter the plateau period, which will drop to 53.43×108 t in 2060. Natural gas consumption in 2030 and 2060 will be about 5 449×108 m3 and 5 280×108 m3 respectively. It is worth noting that under the conditions of relatively low economic growth, the total energy consumption and natural gas consumption in the target year of carbon neutrality have decreased compared with the average year of carbon peak.

In the high-speed scenario, countries around the world benefit from the effective role of COVID-19 vaccines and stable and improving international relations, as well as various regional investment and trade protection agreements, and the global economy accelerates its recovery from the epidemic, while China's economy is efficiently driven by a development pattern dominated by domestic cycles and reinforced by domestic and international cycles, and maintains medium-high growth for a long time. It is expected that the average annual economic growth rate will remain at about 4.5% from 2021 to 2060, 5.5% from 2021 to 2030, and slightly drop to 4.16% after 2030. In this scenario, the elasticity coefficient in 2030 is 0.18, and due to the high economic growth rate, the elasticity coefficient is expected to decline to 0.06 in 2060, which is slightly lower than the base scenario. The total consumption of primary energy will reach 60.78×108 t in 2030, and will continue to increase to 68.20×108 t in 2060, and the consumption of natural gas in 2030 and 2060 will be about 6 006×108 m3 and 6 740×108 m3, respectively.

In order to ensure the accuracy of the model prediction results, the backward inference method was used to calculate the proportion and consumption of natural gas consumption. According to the latest research results of Nature magazine, the average annual carbon absorption of China's terrestrial ecosystem from 2010 to 2016 was about 11.1×108 t[17]. The data of the ninth National forest resources inventory show that the total carbon sink of China's forests is 4.34×108 t, equivalent to 15.91×108 t of carbon dioxide [18], and China's terrestrial ecological carbon sink will be maintained at about 15×108 t in the future. In addition, China's CCUS technology is developing rapidly, and it is estimated that the emission reduction that can be achieved by 2060 is 10×108 ~ 18×108 t of carbon dioxide [19]. Therefore, China's terrestrial carbon sink capacity in 2060 is close to 25×108 ~ 33×108 t. Using this as the carbon emissions allowed in the target year of carbon neutrality, the amount of fossil energy that can be used is 9×108 ~ 12.5×108 t (one ton of standard coal is estimated to emit 2.66 ~ 2.72 t of carbon dioxide), accounting for 13% ~ 24% of the predicted total primary energy consumption. Considering that the main fossil energy in 2060 is natural gas, oil will still be used in a small amount in transportation, and coal will be used in other ways, which proves that the proportion of natural gas in 12% is relatively reasonable, and the prediction of natural gas consumption to reach 5 280×108 ~ 6 740×108 m3 is also relatively accurate.

In general, the decline of fossil energy consumption under the guidance of carbon neutrality goal is an inevitable trend of energy development. In the process of the transformation of energy structure from high-carbon fossil energy to low-carbon and renewable energy, natural gas, as a clean fossil energy, has a relatively optimistic development prospect compared with coal and oil. In the long term, even if carbon neutrality is achieved, natural gas will become a strong support for renewable energy, ensuring a stable supply of energy systems. The above discussion provides a reference case for the future development of natural gas, that is, the proportion of coal and oil consumption in primary energy is very low, and natural gas consumption will continue to grow under the basic conditions of achieving carbon neutrality.

2.3 Main source of natural gas in China

2.3.1 Conventional natural gas, shale gas and coalbed gas

In 2020, China's domestic production of natural gas is 1,888.5 ×108 m3 (excluding coal bed methane), an increase of 9.8% compared with 2019, among which shale gas output is about 200×108 m3, an increase of 39.3% compared with the previous year, accounting for 10.6% of the total annual output [20], becoming the main growth point of natural gas output. In recent years, China's oil and gas exploration and development has continued to increase, and the new reserves and production of natural gas have reached a record high. In 2019, the country's new proved geological reserves of natural gas were 15 800×108 m3, an increase of about 6 000× 108 m3 year-on-year. Among them, the new proved geological reserves of conventional natural gas and shale gas are 8 091×108 m3 and 7 644×108 m3, respectively, and the new technical recoverable reserves are 3 521×108 m3 and 1 838×108 m3, respectively. At present, China's proved geological reserves of conventional natural gas are about 17.64×1012 m3, and that of shale gas is about 2×1012 m3. The Sichuan Basin, the main production area of shale gas, is increasing its development efforts, and its output will continue to increase significantly, becoming the main force of natural gas production increase. In addition, China is also rich in CBM resources, with proven reserves of about 3 040.7×108 m3 in 2019. In 2020, China's coalbed methane production will be 102.3×108 m3, an increase of 13.5×108 m3 and an increase of 15.2% over the previous year [21]. To ensure the stable supply of natural gas, conventional natural gas, shale gas and coal bed methane will all play a fundamental role.