Carbon neutrality means that an enterprise or an organization reduces or offsets its own carbon emissions through energy conservation and carbon reduction, afforestation or other natural or man-made ways within a certain period of time (the measurement period is usually one year). Net-zero emissions refers to the balance between GHG emissions and removals. GHG gases causing global warming include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), etc. To reverse the climate crisis, it is not enough to rely on carbon reduction alone, all the GHG emissions have to be reduced and the carbon-negative technologies also need to be accelerated.

     The Animal Industry Business Division of TSC is currently constructing a green livestock housing combining biogas power generation and solar PV power generation. However, there still lacks a proper way of biogas residue and slurry dematerialization. In addition, the 20-year flat land afforestation subsidy of the afforested land TSC implemented to work in line with government policies is about to expire. How to make an overall plan to continue the utilization of the afforested land will affect the supply and demand of agricultural production in Taiwan and the agricultural development of TSC. If the deregulated forest land near the pig farms can be used to produce energy crops with biogas residues and slurry, that can further be developed into green energy and regional agricultural waste recycling centers, and proper dematerialization of biogas residues and slurry can be made possible while at the same time earn NTD 5.1407/kWh from green electricity generated from agricultural waste.

     Biomass energy is one indispensable part in the planning of global green energy and renewable energy. MOEA also announced the Feed-In Tariffs of renewable energy rates in 2023. The Feed-In Tariffs of agricultural waste remained the same level in 2022, namely NTD 5.0107/kWh, better than general industrial waste. Owing to the fact that in the collection of agricultural waste, there used to be problems of scattered materials, many inclusions, and high labor costs, many countries choose to directly plant energy crops to develop green power. Energy crops shall have the following characteristics: resistant to poor soil, fast growth, high yield, perennial, easy to reproduce, extensive cultivation of perennial roots, strong climate adaptability, resistant to diseases and pests, and easy to manage.

     Among many energy crops, Napier Grass and the Giant King Grass modified from Napier Grass should be more suitable for circular application of TSC’s agriculture and animal husbandry. The annual yield of dry matter per hectare of Napier grass (Pennisetum purpureum), or elephant grass, reaches 50-80 tonnes, and the cellulose content is as high as 40-45%, having great potential to become a new fiber energy crop in tropical and subtropical regions. Moreover, Napier Grass and the Giant King Grass can be mass propagated using stems like sugarcane, and the perennial roots can be cultivated for up to 7 years and are easy to manage. Therefore, TSC can conduct modification experiments based on the existing sugarcane cultivation.

     In the 2021 symposium on the net-zero agricultural emission strategies, the Council of Agriculture (COA) of the Executive Yuan also provided a model of “turning waste into gold- green cycle of agriculture and animal husbandry” where the biogas residues and slurry are irrigated in the nearby Napier grass field, and the Napier grass can then be processed into medium of the mushroom cultivation bags and biofuel. Currently, some manufacturers have contacted Taiwan Sugar Research Institute (TSRI) for cooperation projects.

     Taiwan is one of the few countries in the world that can easily collect oyster shells. TSC’s biological material plant makes calcium carbonate from oyster shells, and the expected amount of oyster shells is about 50,000 tonnes annually, accounting for one-third of the overall production in Taiwan, and the amount of the oyster shells collection tops the world. Currently, TSC’s biological material plant produces oyster shell powder fertilizers, oyster shell powder feed to replace calcium carbonate products. The oyster reef that is yet to be discussed is a rising star in terms of ocean carbon sinks. The National Oceanic and Atmospheric Administration (NOAA) has made the oyster reef restoration the priority for conservation.

    Oyster reefs seem plain and simple, yet it has as great biological functions as coral reefs. Oyster reefs used to be over the oceans and coasts in the world. However, after the industrial revolution, the over-trawling led to its disappearance. Experts estimated that about 85% of the oyster reefs on earth had been destroyed over the past 2 centuries. Now that its importance to carbon sinks in the global carbon cycle has gradually emerged, it is regarded high-efficient and highly potential carbon sink and is therefore being actively restored.

     Oysters can turn carbonate ions in the ocean into calcium carbonate through calcification, and the carbon dioxide is stored in the shells. The duration of its carbon sequestration can reach to millions of years. Calculated based on the 96% calcium carbonate content in oyster shells, every production of 1,000 kg of oyster shells can achieve 425kg of carbon sequestration, which shows the oyster reefs’ strong potential for carbon sequestration. In addition, the oysters on the oyster reefs can effectively purify the seawater by filtering suspended matters and algae, improving the transparency of the water body and the depth of light transmission in the ocean, which is also beneficial to the growth of benthic plants, increasing their absorption and fixation of carbon. It is worthy of further discussion with relevant academic and research units and government departments.