Chinese Academy of Sciences Academician Li Can pointed out that green hydrogen energy is an inevitable progress in achieving carbon neutrality, but many people do not realize that green and low carbon are actually separate.
Written by/Reporter Wang Xueying
"If you want to solve the emission of carbon dioxide , hydrogen energy , especially green hydrogen energy is essential. It is an inevitable progress in achieving carbon neutrality, but many people do not realize that green and low carbon are actually separate - low carbon can include green engineering, but green engineering may not necessarily solve the low carbon problem." On November 3, Li Can, an academician of the Chinese Academy of Sciences and director of the solar energy research department of the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, said this at the 2022 APEC Business Leaders China Forum.
▲Li Can, an academician of the Chinese Academy of Sciences and director of the solar energy research department of the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, said at the theme forum of "Hard Technology and Industrial Development" that carbon dioxide should not be blindly emphasized as a greenhouse waste gas, but should be regarded as a convertible carbon resource. Green hydrogen is converted. With the green hydrogen generated by renewable energy, the recycling of carbon resources can be achieved and sustainable development of mankind can be achieved. After the meeting, the media interview was accepted for issues such as "solar energy conversion efficiency" and "liquid sunlight methanol technology" that are of concern to the society.
Reporter: The utilization rate of solar energy has increased significantly in recent years. How to further improve the efficiency of solar energy conversion? What new basic research results are on the road to transformation and implementation?
Li Can: There are many ways to utilize solar energy, and the most familiar and typical one is photovoltaic power generation. solar photovoltaic power generation has developed very fast in recent years. As for the most representative crystalline silicon batteries, ten years ago, the utilization rate of large-scale industrialization was only more than 10%, but now it has been mentioned that more than 22%, and the laboratory can reach 26%, while in theory its ideal efficiency is 31%. That said, we are almost at the ceiling now.
Solar energy is free for nature. Unlike other chemical conversions, it is different from those of other chemical conversions. In this case, it is no longer an urgent task to talk about increasing a few percent. Compared to efficiency, cost is something that everyone pays more attention to - if you want to make society and accept this technology, you will ultimately have to look at cost.
is also ten years ago. Compared with coal and gas power generation, the cost of photovoltaic power generation is about four times. Except for aerospace and , civil use is almost unimaginable. Today, ten years later, the price of its power grid is about 0.36 yuan, which is almost the "baby price", and the cost is even lower than thermal power. Because of this, my country canceled government subsidies for photovoltaic power generation two years ago, but this did not affect the rapid growth of the photovoltaic market at all. The reason is that the market accepts and recognizes it, and the momentum of independent development is so good.
Reporter: In your opinion, what kind of industrial prospects does liquid sunlight methanol technology have?
Li Can: We say that photovoltaics and wind power are developing very fast, and they can be converted into electricity, but the terminal demand of society is not just electric energy. Many fields such as transportation, cooking and cooking, they are not a necessity for electricity. This requires us to find a way to convert part of the captured solar energy into more convenient energy.
In the past, we proposed to electrolyze water to make hydrogen, make hydrogen and store it, and then use it in various industries such as chemical industry, refining and metallurgy. As a gas, hydrogen has very low density and storage efficiency is too low. What should I do? We react it with carbon dioxide and convert it into liquid methanol, which is stored and transported as a liquid fuel. Because of this, we also gave liquid methanol a particularly vivid name - "liquid sun", which vividly means that the sun can be stored in an oil barrel.
Reporter: In 2020, Lanzhou New District established a demonstration project for liquid solar fuel synthesis. This year, China Coal invested 5 billion yuan in Ordos to start the production of 100,000 tons of liquid sunlight methanol.How do you understand the meaning behind these initiatives?
Li Can: In my opinion, liquid sunshine methanol is actually a "shot of three birds with one stone", which means that hydrogen storage, energy storage and carbon dioxide resource utilization can be "three-pronged". First, it can convert the rapidly developing renewable energy power consumption into methanol that can be stored and transported to achieve hydrogen storage; second, it can alleviate the energy security problem of liquid fuel shortage in my country; third, it can make full use of carbon dioxide resources and reduce carbon dioxide emissions to help carbon neutrality - 1 ton of methanol can absorb 1375 tons of carbon dioxide, and 100,000 methanol can absorb nearly 140,000 tons of carbon dioxide, which is very considerable.
In terms of technology, people have actually discussed many emission reduction plans, but they are not feasible in actual operation. For example, carbon dioxide capture and storage technology has certain hidden dangers and is too high in cost. It is almost a net investment, and it is difficult for enterprises to have the motivation to advance independently. In contrast, liquid sunlight methanol technology not only solves the problem of carbon dioxide, but also produces basic industrial raw materials, which is a win-win situation.
Reporter: Do you think the emergence of emerging technologies such as liquid solar fuel will bring disruptive changes to my country's industrial industry?
Li Can: Some industries may have disruptive potential, such as the production of methanol. In theory, if it can reach a large scale, it is expected to replace my country's gasoline demand. Then we do not need to import a large amount of oil, and we have more initiative and voice in energy security and energy pricing.
Reporter: In the process of promoting enterprises to develop these technologies, what do you think are the most focused problems they are on?
Li Can: Cost. Take liquid sunlight methanol as an example. Its largest investment in the early stage was photovoltaics. This investment cost is very high, and the cost recovery will take at least 10 years, which is a huge burden for many small businesses. Furthermore, what it requires is an integration of multiple technical solutions, rather than a single technology. It is a huge system project, and many small businesses do not have the ability to "eat" such a big "cake". Because of this, the projects we are seeing now are led by large groups.
With the advancement of large-scale industrialization and people's increasingly familiar with technology, the entire system engineering will definitely be further narrowed and streamlined. With the first successful example, it will be easier to do.
Reporter: In recent years, "energy storage" has also been a topic that people often talk about.
Li Can: Yes, photovoltaic power generation can generate electricity during the day, but it cannot be done at night, but the power grid cannot withstand such tossing. What the power grid needs is stable output. If energy is stored, part of the electricity can be even out during the day and then released at night.
In terms of large-scale energy storage, what we talk about now is "water-light complementarity", that is, a reservoir is originally generating electricity. When water gathers during the day, it generates less electricity. It mainly uses sunlight during the day to generate electricity. When there is no sunlight at night, it will control the water and electricity to replenish it. my country now has a good example of "water and light complementary" energy storage - Qinghai's Longyangxia Hydropower Station . Through calculation and control, it has been supplying power to the lower reaches of the Yangtze River very stably. However, the "water and light complementarity" model has high requirements for geographical conditions.
In addition, I have been mentioning " photothermal power generation " in recent years. It does not require water and electricity to "find" it, but is stored as heat energy. By regulating the heat medium, it can generate electricity smoothly like thermal power when needed. At present, the materials for this technology are already available, but the cost needs to be reduced.
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