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

3.2 Coupling development scenario

The coupled development scenario refers to the cooperative layout of natural gas and renewable energy resources such as photovoltaic, wind power, hydropower, hydrogen energy and geothermal energy. Through the joint innovation of energy utilization technology and information and communication technology, natural gas can be flexibly and efficiently embedded with renewable energy in the upstream, middle and downstream links of production and development, storage, transmission and distribution, consumption and utilization, and in accordance with local conditions. We will promote a new development model in which various energy sources complement each other.

With the rapid development of energy Internet and information technology, 5G, artificial intelligence and other information technologies will accelerate the penetration and integration of the energy industry, natural gas and renewable energy deep coupling development conditions are becoming more mature, and the coordination of energy system operation and resource utilization efficiency will be greatly improved.

3.2.1 Upstream Production

In the process of natural gas development, the utilization of new energy can be strengthened, and the transformation of traditional oil and gas production mode to green energy production mode can be promoted. Specifically, more electric drilling and electric drive fracturing technologies can be used, and wind, solar, and geothermal energy can be used as power sources according to local conditions. The oil and gas field station can also give priority to the use of wind power, photovoltaic power, and mains power as a supplement to achieve energy greening.

In the process of unconventional natural gas development, CCUS technology is introduced, as shown in Figure 5, to strengthen the promotion and application of carbon dioxide intensive development shale gas technology, improve the development effect of tight gas reservoirs, complete the storage and utilization of carbon dioxide, and achieve zero carbon emission or even negative carbon emission. In addition, methane itself is an important greenhouse gas, and its greenhouse effect is much higher than that of carbon dioxide, so it is necessary to effectively control methane emissions in the process of natural gas exploitation to ensure the high-quality development of the natural gas industry.

3.2.2 Storage and transportation

Develop "electricity to gas + natural gas pipeline network" and other related technologies. With the increasing distribution of energy, energy transmission will face increasing challenges, compared with electricity transmission, gas network transmission losses are lower. The technology of hydrogen production from renewable energy combined with hydrogen transportation in natural gas pipeline network is an effective way to solve the utilization and transportation of hydrogen energy and overcome the problem of large-scale wind and electricity absorption. Since 2004, many countries around the world have studied the relevant application technologies of natural gas mixing hydrogen. In 2012, Germany established the world's first "wind power hydrogen production - natural gas pipeline hydrogen transport" application demonstration project, Uniper energy storage company in Falkenhagen, Brandenburg combined wind power and alkaline electrolysis technology to produce hydrogen, the green hydrogen directly into the natural gas pipeline, the proportion of hydrogen mixing is 10%. In 2018, the company used PEM electrolysis (polymer electrolyte membrane electrolysis) technology to deliver higher purity hydrogen into the natural gas network in Hamburg, Germany. In 2019, the German state of Saxony-Anhalt launched a natural gas pipeline transportation project with a hydrogen content of 20% in Schopsdorf [33]. The construction of China's natural gas infrastructure and transmission and distribution network has been relatively complete. As of 2019, the mileage of China's natural gas trunk pipelines exceeded 8.7×104 km, and the gas transmission capacity exceeded 3 500×108 m3/a. With the establishment and operation of the National Oil and Natural Gas Pipeline Network Group, the construction and management of pipeline networks are expected to reach a new level. It is suggested that some existing natural gas infrastructure and pipeline network should be reformed to adapt to the transportation of hydrogen-doped natural gas.

Using "electricity to gas + gas storage" to achieve the conversion and storage of renewable energy. As an important energy conversion technology and energy storage means, electricity to gas technology (such as electrolysis of water to produce hydrogen) can realize the purpose of "storing" wind energy and solar energy. At the same time, using depleted oil and gas reservoirs, underground salt caverns, etc., carbon dioxide collected through carbon capture technology and hydrogen produced from renewable energy through microbial catalysis, etc., to achieve carbon dioxide hydrogenation and methanation, produce biomethane, and complete large-scale conversion of renewable energy into low-carbon clean energy such as methane. In addition, carbon dioxide and hydrogen can also be used to produce methanol, methanol chemical characteristics are stable, easy to transport, is a clean and efficient high-quality fuel, but also an important chemical raw material.