New opportunities for biomass energy development in the context of carbon neutrality



Biomass energy has unique advantages in "heat-electricity" and energy storage, and can bring "negative carbon" opportunities

Biomass is an eco-friendly, zero-carbon energy source that has obvious advantages over other commercially available energy sources today.

First, the environmental externality of biomass energy is low, which is conducive to the realization of circular economy. For example, biomass power generation provides an effective way for the treatment and utilization of agricultural and forestry waste, which helps to reduce the open burning of straw and the environmental pollution it brings. In this process, the ash generated after biomass combustion can also be used as an organic fertilizer, so as to realize the recycling of agricultural and forestry waste and "turn waste into treasure". In addition, the promotion of biomass fuel to replace coal in industrial production is also a way to reuse biomass resources and help achieve carbon reduction in the industrial sector.

Second, the use of biomass energy can solve the problem of electricity and heat at the same time, which is an advantage that other forms of renewable energy use such as wind power and photovoltaic power generation do not have. Due to the limitations of technology, land and the characteristics of wind and water renewable energy, China will focus on large-scale heat pump technology to solve the heating problem through electrification in the future, and it still faces many challenges. Therefore, another possibility is to retain some of the thermal power in the new power system of the future, and make it also heat (as discussed below). Then, in this scenario, biomass energy will also play a role in power supply and heating, and show its zero-carbon advantage.

Third, biomass can help solve energy storage problems at different time scales, and provide support for the construction of a new, safe and stable power system with renewable energy as the main body. In this regard, biomass can be used as an energy option to solve energy storage problems on different time scales, including hourly, cross-day, cross-week and even cross-season.

Fourth, biomass presents an opportunity to go carbon negative and contribute significantly to rural revitalization. Biomass resources effectively absorb atmospheric carbon dioxide in the growth process, although the process of being used as fuel or industrial raw materials will emit carbon dioxide into the atmosphere, but from the perspective of the whole cycle can achieve "net zero" emissions of carbon dioxide. On this basis, if combined with CCS technology, the carbon dioxide emitted can be captured and stored, it can achieve valuable carbon dioxide "negative emissions", which will undoubtedly help the realization of carbon neutrality goals. In this context, it can be predicted that the further development of the biomass industry will drive rural economic growth, help eliminate rural energy poverty, and achieve rural revitalization.

Facing the bottleneck of large-scale commercialization, it is necessary to seize the opportunity of "carbon neutrality" to make a breakthrough

Biomass in China is not a new thing, has experienced a certain period of development. However, up to now, the development scale of China's biomass industry is still limited. Taking the power industry as an example, according to the information of the National Energy Administration, by the end of 2021, China's installed biomass power generation capacity reached 37.98 million kilowatts, accounting for only about 3.6% of the total installed renewable energy power generation capacity; In contrast, wind power and photovoltaic power installed capacity has reached 328 million kilowatts and 306 million kilowatts, respectively. Fundamentally, there are two reasons worth exploring:

First, due to the limitations of many factors, biomass has not formed large-scale commercialization. Different from coal, gasoline, natural gas, wind energy, solar energy and other energy sources that have been able to achieve centralized and large-scale utilization, the large-scale utilization of biomass resources faces constraints such as dispersed resource distribution, wide range and low accumulation density, which makes its collection, storage, processing and transportation very different and more difficult from other energy sources, so a complete industrial chain has not yet been formed. The scale of commercialization is not enough. From the property of biomass itself, compared with coal, oil, natural gas and other fossil energy, the energy density of biomass is relatively low, so the heat generated by the same volume or mass is also relatively low; From the perspective of availability and scale, the distribution of biomass resources is relatively dispersed, wide range and difficult to use directly, which leads to the high cost of collection, storage, processing and transportation, hindering the formation of a complete industrial chain and limiting the development of scale; From the perspective of technology, the utilization of advanced biomass technology in China is generally in an immature stage. Developed countries have obvious first-mover advantages in the field of biomass resource utilization and product manufacturing, and the monopoly of core technologies makes China rely on imports of many key technologies and key equipment for biomass conversion and utilization. From the policy point of view, for a long time, the absence of encouraging policies and incentives, coupled with the failure of some early demonstration projects, has also made biomass energy, like other renewable energy sources, has not been able to obtain the policy support and more market confidence. In summary, under the comprehensive effect of various factors such as its own attributes, storage efficiency, transportation costs, technical equipment, policy measures, and market confidence, the development of biomass energy faces the problems of high industrial costs and limited large-scale production, and has not yet formed large-scale commercial applications.

The second is that biomass energy has not encountered transformational development opportunities before. The establishment of the goal of carbon neutrality has put forward a huge and urgent demand for systemic change in China's energy development in the future, which provides a rare opportunity for the further development and utilization of biomass energy. According to the energy ladder theory, the biomass energy used in this stage is at the lowest level of the energy ladder, "initial energy", and the ladder above it is "transition energy" (charcoal, coal, kerosene), "quality energy" (electricity, liquefied petroleum gas/natural gas, biogas). However, under the opportunities brought by carbon neutrality, biomass will likely appear in different forms in different application scenarios, and it is likely to achieve a grade leap on the ladder of energy varieties. Especially under the common needs of clean power and cogeneration in the future, biomass energy can not only help clean power generation and clean heating, but also have the opportunity to achieve negative carbon emissions. In the context of carbon neutrality, the stage for biomass to play a role will be wider.

Biomass energy has a unique role in the clean supply of electricity and heat and should not be simply compared with scenery

First, biomass energy is fundamentally different from wind and solar energy in nature, and therefore its role in the power system will be different. In the future, biomass energy is not simply seeking to contribute a high proportion of electricity generation in the entire power system, but to play a unique role in the system.

The intermittent characteristics of renewable energy will bring some challenges to the stability of the new power system based on wind and light. For example, if there is no wind for several days, or if it is persistently cloudy, or if it catches up with the winter dry season, the problem of system stability will be highlighted. The current electrochemical energy storage technology can only cope with hour-level peak cutting and valley filling, and the energy storage problem on a longer time scale has not yet found a zero-carbon solution that is mature in terms of economic and technical feasibility. Therefore, for the stability of the power system, it is necessary to retain a certain proportion of thermal power - in the context of current existing and foreseeable technical conditions, there is basically a consensus in all circles on this point. The further question, then, will be, what is the source of fuel for this part of the thermal power? If the starting point is a zero-carbon future scenario, possible options include coal power plus CCS/CCUS (carbon capture and storage/utilization), or replacing coal with green hydrogen, or replacing coal with biomass.

This is why the economic viability of biomass energy needs to be compared with the economic viability of technologies such as CCUS and the use of hydrogen energy for cross-season energy storage. The task of biomass energy is to solve the instability problem caused by wind and light power generation in the future new power system. At present, this problem is electrochemical energy storage, pumped storage can not be solved temporarily.

In addition to power generation, another unique role for biomass lies in heating. Heating is one of the most difficult problems to solve in the process of achieving carbon neutrality. It is directly related to people's livelihood, the energy demand is huge, must be stable and secure. In the context of carbon neutrality, how to solve the heating problem in the northern region in the future, the current discussion mainly involves two ways: one is to consider centralized heating, using renewable energy generated by heat pump to heat; The other is to preserve the existing heat network, so that a part of the thermal power needs to be retained.

At present, the first way faces several challenges: First, China's urban population density is very high, especially in winter, that is, photovoltaic power generation and hydropower are in the trough period, may need to increase a very large amount of installed capacity to ensure the power supply required for heating, which may make the power grid overwhelmed; Second, under the existing technical conditions, the city does not have enough land space to install centralized heat pump; Third, in this case, there is a risk that infrastructure such as heat grids will become a sunk asset in the future.

While we have high hopes for electrification, we are also supporting efforts in rural areas and small towns in the south and north. However, the author believes that based on China's national conditions, in large and medium-sized cities in the north where the population is concentrated, the second way is more feasible, that is, in the future, a part of the new power system needs thermal power, and this part of thermal power can also play the role of heating. In the process, biomass will have the opportunity to take advantage of its zero-carbon advantages in both electricity and heating.

Therefore, biomass energy may not contribute the largest proportion of electricity generation in the entire new power system in the future, but it can certainly play a unique and critical role in the clean supply of electricity and heat.

We should promote diversified development and utilization of biomass energy

The development and utilization of biomass energy is pluralistic. Biomass power generation is the most mature, the largest development of modern biomass energy utilization technology, Nordic countries, Germany and the United States in the world's leading level. China's biomass power generation started late, and the current scale of development is still limited. As mentioned above, by the end of 2021, the cumulative installed capacity of biomass power generation in China has reached 37.98 million kilowatts, accounting for about 3.6% of the total installed capacity of renewable energy power generation, and biomass power generation is 163.7 billion KWH, accounting for about 6.6% of the total renewable energy power generation. From the cumulative grid-connected biomass power generation, China is currently dominated by waste incineration power generation and agricultural and forestry biomass power generation, and biogas power generation accounts for only about 3%. The technology classification of biomass power generation is rich, including direct combustion, mixed combustion, waste incineration, biogas, gasification power generation, etc. In the initial application of biomass power generation technology, it is necessary to promote diversified development and pilot projects, so as to find out the role and advantages and disadvantages of different biomass power generation technologies in different application scenarios, and then promote the large-scale application of biomass power generation technology in different scenarios according to local conditions. At the same time, if BECCS (Bioenergy and carbon capture and storage) technology can be applied at scale in the future, biomass power generation will have the potential to create negative carbon emissions, which can make a great contribution to achieving carbon neutrality goals.

Biomass clean heating is another potential application scenario. As mentioned above, biomass energy has unique advantages in providing clean electricity and clean heat, so in the future, on the one hand, it can promote the transformation and upgrading of biomass power generation to cogeneration according to local conditions, and on the other hand, it can develop biomass boilers based on agricultural and forestry biomass and biomass molding fuel to provide central heating for densely populated large and medium-sized cities and urban areas. As far as biomass solid molding fuel technology is concerned, Europe and the United States are at the global leader level, mainly due to the relatively perfect standard system, and the formation of the entire industrial chain from raw material collection, storage, pretreatment to the production, distribution and application of molding fuel. Europe is the main consumption area of biomass molding fuel, of which Sweden biomass molding fuel heating accounts for about 70% of its total heating energy consumption. This shows the importance of establishing a complete industrial chain and the huge potential of biomass energy in clean heating.

At present, bio-liquid fuels have become the most promising alternative fuels, and in the field of transportation power that electrification cannot solve, bio-liquid fuels provide valuable zero-carbon solutions. In the field of biodiesel, China's related industry technology is in the first echelon in the world, and it is the second largest source country of biodiesel technology in the world after the United States, and China's biodiesel patent applications account for 17% of the world's total (as of September 2021). In 2021, China's biodiesel production is about 1.5 million tons, accounting for about 3.6% of global production, after the European Union, Indonesia, the United States, Brazil and other economies. In the biological aviation fuel technology, China has made a breakthrough, to achieve the biomass hemicelluloses and cellulose co-conversion synthetic biological aviation fuel, has now taken the lead in the international demonstration application stage. In addition, second-generation ethanol as a vehicle and aviation fuel, biological methanol, green ammonia as a vehicle and shipping fuel (especially ocean), are biological liquid fuel in the future with potential application scenarios, related technologies are in the breakthrough or experimental stage. In this regard, the "14th Five-Year Plan" renewable energy Development Plan proposes to support the research and development and promotion of advanced technological equipment in the field of biomass liquid fuel, which will promote the breakthrough of biological liquid fuel technology in different scenarios from "test" to "application".

Bio-natural gas is an important zero-carbon energy that can be used in power, heating, transportation and other fields. As early as 2019, the National Development and Reform Commission, the National Energy Administration and other ten ministries and commissions jointly issued the "Guiding Opinions on Promoting the Development of Bio-gas Industrialization", which proposed that the annual output of bio-gas should exceed 20 billion cubic meters by 2030. According to relevant estimates, China's biological natural gas can be exploited as much as 60 billion cubic meters per year, but as of 2020, China's actual annual output of biological natural gas is less than 100 million cubic meters. This shows that the development of bio-gas in China is still in its infancy, and it also means that there is great potential. Also as proposed in the "14th Five-Year Plan" renewable energy development Plan, we should effectively make good use of the advantages of abundant resources of agriculture and forestry industry in China, coordinate the concentrated production areas of grain, forest and livestock, establish an industrial system with the county as a unit, and actively carry out biological natural gas demonstration projects. In this process, it is necessary to build a large-scale (tens of millions of cubic meters) biological gas project, so that through the grid connection with the city gas pipeline network, diversified applications (vehicles, boilers, power generation), greatly promote the large-scale use of biological gas, accelerate the decarbonization process of the energy system.

The multiple development and utilization of biomass energy is of great significance to rural revitalization. As mentioned in the "14th Five-Year Plan for Renewable Energy Development", increasing the development and utilization of biomass energy and improving the utilization rate of agricultural and forestry wastes will help improve the rural living environment. The use of biomass energy and other renewable energy sources in heating projects can help improve rural heating conditions and facilitate the construction of a clean heating system that integrates urban and rural areas. The intensive development and efficient operation management of rural renewable energy resources can be realized by building rural energy stations mainly based on biomass molding fuel processing stations or material boilers. The construction of large-scale bionatural gas projects will also help to promote the establishment of circular industrial systems for organic waste treatment, organic fertilizer production and consumption, and clean gas utilization in rural areas - all of which will bring new opportunities for eliminating rural energy poverty, expanding the comprehensive utilization of rural renewable energy, and promoting sustainable social and economic development in rural areas.