The energy used in global electrolytic aluminum production depends on the resource endowment of each region. Among them, coal and hydropower accounted for 85% of the energy used. In the global electrolytic aluminum production, the electrolytic aluminum plants in Asia, Oceania and Africa mainly rely on thermal power generation, and the electrolytic aluminum plants in Europe and South America mainly rely on hydropower. Other regions depend on their resource characteristics, and the energy used by electrolytic aluminum plants also varies. For example, Iceland uses geothermal energy, France uses nuclear power, and the Middle East uses natural gas to generate electricity.
According to the author's understanding, in 2019, the global production of electrolytic aluminum was 64.33 million tons, and the carbon emission was 1.052 billion tons. From 2005 to 2019, the total global carbon emissions of electrolytic aluminum increased from 555 million tons to 1.052 billion tons, an increase of 89.55%, and a compound growth rate of 4.36%.
1. The impact of "double carbon" on the aluminum industry
According to estimates, from 2019 to 2020, the electricity consumption of domestic electrolytic aluminum will account for more than 6% of the national electricity consumption. According to Baichuan Information data, in 2019, 86% of domestic electrolytic aluminum production uses thermal power. According to Antaike data, in 2019, the total carbon dioxide emission of the electrolytic aluminum industry was about 412 million tons, accounting for about 4% of the national net carbon dioxide emission of 10 billion tons in that year. The emission of electrolytic aluminum is significantly higher than that of other metals and non-metallic materials.
The self-provided thermal power plant is the main factor leading to the high carbon emission of electrolytic aluminum. The power link of electrolytic aluminum production is divided into thermal power production and hydropower production. Using thermal power to produce 1 ton of electrolytic aluminum will emit about 11.2 tons of carbon dioxide, and using hydropower to produce 1 ton of electrolytic aluminum will emit almost zero carbon dioxide.
The electricity consumption mode of electrolytic aluminum production in my country is divided into self-supplied electricity and grid electricity. At the end of 2019, the proportion of self-provided electricity in domestic electrolytic aluminum plants was about 65%, all of which were thermal power; the proportion of grid power was about 35%, of which thermal power accounted for about 21% and clean energy power generation accounted for about 14%.
According to Antaike's calculations, under the background of the "14th Five-Year Plan" energy saving and emission reduction, the energy structure of the electrolytic aluminum industry's operating capacity will undergo certain adjustments in the future, especially after the planned electrolytic aluminum production capacity in Yunnan Province is fully put into operation, the proportion of clean energy used will increase significantly, from 14% in 2019 to 24%. With the overall improvement of the domestic energy structure, the energy structure of the electrolytic aluminum industry will be further optimized.
2. Thermal power aluminum will gradually weaken
Under my country's commitment to carbon neutrality, thermal power "weakening" will become a trend. After the implementation of carbon emission fees and strict regulation, the advantages of self-owned power plants may be weakened.
In order to better compare the cost difference caused by carbon emissions, it is assumed that the prices of other production ingredients such as pre-baked anodes and aluminum fluoride are the same, and the carbon emissions trading price is 50 yuan/ton. Thermal power and hydropower are used to produce 1 ton of electrolytic aluminum. The carbon emission difference of the link is 11.2 tons, and the carbon emission cost difference between the two is 560 yuan/ton.
Recently, with the rise of domestic coal prices, the average electricity cost of self-provided power plants is 0.305 yuan/kWh, and the average domestic hydropower cost is only 0.29 yuan/kWh. Under the influence of high cost, most of my country's new electrolytic aluminum projects are located in the hydropower-rich areas in the southwest region, and thermal power aluminum will gradually realize industrial transfer in the future.
3. The advantages of hydropower aluminum are more obvious
Hydropower is the lowest cost non-fossil energy in my country, but its development potential is limited. In 2020, my country's hydropower installed capacity will reach 370 million kilowatts, accounting for 16.8% of the total installed capacity of power generation equipment, and it is the second largest conventional energy resource after coal. However, there is a "ceiling" in the development of hydropower. According to the review results of national hydropower resources, my country's hydropower development capacity is less than 700 million kilowatts, and the future development space is limited. Although the development of hydropower can increase the proportion of non-fossil energy to a certain extent, the large-scale development of hydropower is limited by resource endowments.
At present, the current status of hydropower in my country is that small hydropower projects are closed down, and large hydropower projects are difficult to add. The existing hydropower production capacity of electrolytic aluminum will become a natural cost advantage. In Sichuan Province alone, 968 small hydropower stations need to be withdrawn from shutdown, 4,705 small hydropower stations need to be rectified and withdrawn, 41 small hydropower stations have been shut down in Quanzhou City, Fujian Province, and 19 small hydropower stations have been shut down in Fangxian County, Shiyan City, Hubei Province. Hydropower stations and Xi'an, Shaanxi shut down 36 small hydropower stations, etc. According to incomplete statistics, more than 7,000 small hydropower stations will be closed by the end of 2022. The construction of large-scale hydropower stations requires resettlement, the construction period is generally long, and it is difficult to build in a short period of time.
4. Recycled aluminum will become the future development direction
Electrolytic aluminum production includes 5 stages: bauxite mining, alumina production, anode preparation, electrolytic aluminum production and aluminum ingot casting. The energy consumption of each stage is: 1%, 21%, 2%, 74%. and 2%. The production of secondary aluminum includes 3 stages: pretreatment, smelting and transportation. The energy consumption of each stage is 56%, 24% and 20%.
According to estimates, the energy consumption of producing 1 ton of recycled aluminum is only 3% to 5% of the energy consumption of electrolytic aluminum. It can also reduce the treatment of solid waste, waste liquid and waste residue, and the production of recycled aluminum has obvious advantages of energy saving and emission reduction. In addition, due to the strong corrosion resistance of aluminum, except for some chemical containers and devices made of aluminum, aluminum is hardly corroded during use, with very little loss, and can be recycled many times. Therefore, aluminum is highly recyclable, and the use of scrap aluminum to produce aluminum alloys has significant economic advantages over electrolytic aluminum.
In the future, with the improvement in purity and mechanical properties of recycled aluminum alloy ingots and the development of casting technology, the application of recycled aluminum will gradually penetrate into the construction, communication, electronics and packaging industries, and the application of recycled aluminum in the automotive industry will also continue to expand. .
The secondary aluminum industry has the characteristics of saving resources, reducing external dependence on aluminum resources, environmental protection and economic advantages. The healthy development of the secondary aluminum industry, with great economic, social and environmental value, has been encouraged and strongly supported by national policies, and will become the biggest winner in the context of carbon neutrality.
Compared with electrolytic aluminum, secondary aluminum production greatly saves land, water and electricity resources, is encouraged by national policies, and also provides development opportunities. The production process of electrolytic aluminum has high energy consumption. Compared with the production of the same amount of electrolytic aluminum, the production of 1 ton of recycled aluminum is equivalent to saving 3.4 tons of standard coal, 14 cubic meters of water, and 20 tons of solid waste emissions.
The secondary aluminum industry belongs to the category of renewable resources and circular economy, and is listed as an encouraged industry, which helps enterprises to obtain national policy support in terms of project approval, financing and land use. At the same time, the state has issued relevant policies to improve the market environment, clean up unqualified enterprises in the secondary aluminum industry, and remove backward production capacity in the industry, clearing the way for the healthy development of the secondary aluminum industry.