In the midst of the growing challenges of the global energy crisis and climate change, biomass energy, with its renewable and carbon-neutral properties, is becoming a highly sought-after sustainable solution in the energy sector. But what exactly is biomass energy? What types does it include? And how do these types of biomass impact our energy future? Next, we'll delve deeper.
Biomass energy is a heterogeneous source of energy from a wide range of sources. According to the European Renewable Energy Directive, biomass encompasses the biodegradable fraction of products, wastes and residues of biological origin from agriculture, forestry and related industries, as well as the biodegradable fraction of biological origin from industrial and municipal waste. From agricultural straw and forestry pruning residues to livestock manure and municipal food waste, all fall under the category of biomass. Of these, wood is the most widely used material for bioenergy production, whether it is pellets, wood chips, or firewood, and by burning these organic materials, heat, fuel, and electricity can be generated.
Agricultural waste is an important source of biomass energy. Straws and rice husks from harvested crops, peels from fruits, and stumps from orchard pruning are all high-quality biomass feedstocks. In large agricultural countries, this type of waste has a stable source and is an energy resource with great potential for development. For example, China produces a huge amount of crop residues every year, and the rational use of these residues can not only solve the environmental pollution problem caused by incineration, but also be transformed into clean energy.
Residues from forestry production and management are also not to be underestimated. Bark and sawdust from logging and pruning waste from forest management are all high-quality woody biomass fuels. Utilizing these materials reduces fire hazards associated with the accumulation of forest waste and improves resource utilization.
With proper treatment, livestock manure can be turned into biogas or dry fuel. In rural areas, small-scale biogas projects utilize livestock manure to produce biogas by fermentation, which is used for household cooking and lighting, effectively solving the problem of rural energy supply and improving rural environmental health.
The organic part of municipal waste, such as kitchen waste and yard trimming waste, can also be transformed from waste to energy through biomass conversion technology. This not only reduces the pressure on landfills, but also provides green energy for cities.
Herbaceous Crops: Herbaceous energy crops are mostly perennial herbaceous plants like willowherb jacaranda, manzanita, and bamboo. They usually take 2-3 years to reach full production capacity, after which they can be harvested annually. These crops not only provide biomass feedstock, but also improve soil and water quality and provide habitat for wildlife.
Woody Crops: Short rotation woody crops, such as hybrid poplar and hybrid willow, grow rapidly and can be harvested 5 - 8 years after planting. These trees absorb carbon dioxide as they grow, helping to mitigate the greenhouse effect.
Agricultural crop residues include corn stover, wheat straw, and rice straw. In the U.S., farmers sell corn stover to local biorefineries, which not only increases their income, but also realizes the secondary use of resources.
Forestry residues are divided into two categories: branches and tops left after logging, and whole trees harvested specifically for biomass energy. Rational utilization of these forestry residues can reduce the risk of forest fires and promote the healthy development of forest ecosystems.
Algae cover microalgae, macroalgae and cyanobacteria that synthesize biomass using sunlight and nutrients. Algae can grow in a variety of water bodies, including freshwater, seawater, and industrial wastewater, and the lipids, proteins, and carbohydrates in their bodies can be converted into a variety of biofuels and products.
Wastes such as sawdust, bark, and twigs from wood processing can be converted into biofuels or bioproducts. Since these residues can be collected at the point of processing, they are a convenient and relatively low-cost source of biomass energy.
Yard trimmings, paper, plastics, and food scraps from municipal waste can be segregated and processed for bioenergy production, reducing the amount of waste going to landfills.
Wet waste includes commercial and household food waste, sludge from municipal sewage treatment, and livestock manure. The biogas produced from these wet wastes is an important source of biomass energy, creating economic value while solving waste disposal problems.
The most direct way to utilize biomass is to release thermal energy through combustion for heating or hot water production. In homes, biomass boilers are fueled by wood pellets or compressed straw to provide warmth for the house; in industry, the heat produced by biomass combustion can meet the heating needs of industrial boilers with high combustion efficiency.
Biomass can be gasified or burned to drive steam turbines and internal combustion engines to generate electricity. Biomass power generation technology has been widely used in many countries, such as Denmark, where biomass power plays an important role in its energy mix, providing clean electricity for industry, commerce and households.
Biomass can be processed into a variety of fuel forms. Solid fuels, such as wood pellets and compressed straw, can be used to replace coal for heating; liquid fuels, such as biodiesel and bioethanol, can be used in transportation; and gaseous fuels, such as biogas, can be used as residential gas. The wide application of these fuels effectively reduces the dependence on fossil fuels.
Biomass industrial boilers generate heat and energy by burning biomass. Unlike traditional boilers fueled by natural gas and coal, biomass boilers are fueled by agricultural, forestry, urban and industrial residues, which have a much lower environmental impact.
Their energy conversion processes are mainly direct combustion and thermo-chemical treatment. Direct combustion is the most common method, and the heat released from the combustion of biomass can be used for building heating, hot water supply or to generate electricity through a steam turbine. Thermochemical treatment converts biomass into liquid or gaseous fuels such as renewable diesel and methane.
The use of biomass industrial boilers has significant advantages. From an environmental point of view, the carbon in biomass fuels participates in the natural carbon cycle, and the carbon emissions after combustion are almost zero; from an economic point of view, it can reduce the energy costs of enterprises and help sustainable development.
Biomass fuels have a lower energy density and lower calorific value per unit weight than fossil fuels such as coal and petroleum, which means that more biomass fuels need to be consumed to produce the same amount of energy, increasing the need for storage and transportation. At the same time, biomass fuels usually have a high water content, which not only reduces combustion efficiency, but also increases transportation costs due to increased weight. Therefore, reducing the moisture content of fuels is the key to improving utilization efficiency and controlling costs.
Biomass fuel supply is significantly affected by seasonality. Agricultural waste is concentrated during the harvesting season; forestry residues are affected by the logging cycle; and although the supply of livestock waste and municipal garbage is relatively stable, it can be disturbed by weather and regional factors. To ensure stable supply, biomass energy projects need to have the ability to flexibly adjust production schedules and store fuel on a large scale.
To reduce costs, on-site consumption strategies can be adopted, such as farms and forests directly using local waste to supply energy for boilers or biogas plants; controlling transportation distances within 50 miles to reduce long-distance transportation costs; and drying and compressing fuels to improve energy density and reduce storage and transportation costs.
The combustion of biofuels produces fewer harmful emissions than other energy sources, helping to reduce air pollution and meet stringent local government air quality regulations.
The biofuel production process can utilize organic waste generated by factories and enterprises, reducing waste disposal costs, promoting the development of a circular economy, and improving the economic efficiency of enterprises.
While traditional energy prices are highly affected by market fluctuations, biofuel prices are relatively stable, which facilitates better budget and cash flow planning for enterprises.
The use of biomass energy relies on local supply chains, which can drive local employment, promote regional economic development and improve the relationship between businesses and local communities.
Biomass energy is rich in types, from agricultural and forestry residues to municipal waste, and contains great energy potential. Its diverse utilization modes and significant environmental and economic advantages make it an important player in the global energy transition. With the continuous progress of technology and the continued expansion of applications, biomass energy will certainly contribute more to the realization of sustainable development goals. In the future, we should further strengthen the research and development of biomass energy, so that this green energy can better serve the human society.
