Technological Innovations in Biomass Conversion: Improving Efficiency and Reducing Emissions

Biomass is organic material produced through the process of photosynthesis, either in the form of products or waste. Examples of biomass are plants, trees, grass, sweet potatoes, agricultural waste, forest waste, feces, and livestock manure. In addition to being used for food, animal feed, vegetable oil, building materials and so on, biomass is also used as a source of energy or fuel. The type of biomass used as fuel is a material that has low economic value or is waste after its primary product is taken. The advantage of biomass energy sources is that biomass is a renewable energy source so that it can provide a sustainable energy source. The basic principle of biomass is that plants will absorb energy from the sun through the process of photosynthesis by utilizing water and nutrients from the soil and CO2 from the atmosphere which will produce organic material to strengthen tissue and form plant structures. When biomass is converted into energy, CO2 will be released into the atmosphere. At this stage, the CO2 cycle will be shorter compared to CO2 produced from burning petroleum or natural gas. This means that the CO2 produced has no effect on the CO2 balance in the atmosphere. So, this excess is utilized to support the creation of sustainable energy.

The consequence of using this energy is its impact, namely increasing levels of carbon dioxide in the atmosphere. The more it is used, the more severe the impact it causes. On the other hand, the use of this energy greatly contributes to global warming and climate change. Therefore, the use of fossil fuels in the future must be replaced immediately. Future energy utilization refers to the use of alternative energy that provides more benefits for both human life and the environment. The energy sector continues to play a major role in the national economy and is a strategic factor. Not only as the main source of state revenue in the APBN, but also by distributing energy, industrial raw materials, creating jobs, attracting investment, and supporting regional prosperity. As an agricultural country with many rice fields and plantations, it will not be difficult to get agricultural waste in Indonesia, especially waste from rice fields and oil palm plantations. In this case, palm oil waste is considered to have its own industry and market to be utilized. However, waste from rice and other plants, such as corn, sugar cane, and others, is undoubtedly lacking in its utilization. In every post-harvest land, for example, there are still remnants of burnt husks which indicate that rice waste is not managed properly. Indonesia continues to experience increasing energy demand due to economic and population growth. The average growth of Indonesia's energy demand over the past ten years is around 7%. Given its relatively small fossil fuel resources, Indonesia faces difficulties in supplying sustainable energy. Indonesia has a population of around 3.4% of the global population, although its fossil fuel reserves are much smaller. Indonesia really has great potential for renewable energy.

Based on Presidential Regulation number 112 of 2022 concerning the acceleration of the development of new renewable energy (EBT) for the provision of electricity, biomass is one of the EBT sources that has great potential to be utilized. One of them is as fuel for Biomass Power Plants (PLTBm) and the implementation of co-firing in PLTU. This is in line with Indonesia's commitment to achieve 23% EBT by 2025. In 2023, a reduction in emissions of 1.05 million tons of CO2 occurred due to the implementation of co-firing in 43 PLTUs consuming 1 million tons/year of biomass.

Indonesia's commitment to achieve 23% EBT by 2025 is a form of fulfillment of the objectives of the National Energy Policy (KEN) and the Paris Agreement to the United Nations Framework Convention on Climate Change (paris agreement on the framework convention of the united nations on climate change) in 2015, where Indonesia is committed to reducing greenhouse gas emissions by 29% (834 million tons of CO2) and 41% (1.081 million tons of CO2) with international support for greenhouse gases BAU / Business As Usual (2869 million tons of CO2) by 2030 with the hope that Indonesia will achieve Net Zero Emissions (NZE) like developed countries. The Minister of Energy and Mineral Resources (ESDM) said in a panel discussion "The Road to COP26: Identifying Indonesia's Young Generation to Combat Climate Change and Support Clean Energy" that the NZE program is committed to the country's development and industry to achieve zero CO2 emissions by 2060.

Table 1. Data on several PLN PLTUs that have carried out co-firing Source: PLTU PLN

PLTU	Capacity (MW)	Types of Biomassa
Paiton	800	Sawdust
Jeranjang	150	SRF-Garbage
Sanggu	14	Palm Shell
Ketapang	20	Palm Shell
Suralaya	1600	Rice Husk
Barru	100	SRF-Garbage
Pacitan	630	Sawdust
Anggrek	56	SRF-Garbage
Rembang	630	Wood Pellet
Labuan	600	SRF-Garbage
Lontar	945	Rice Husk
Adipala	660	Sawdust
Pelabuhan Ratu	1050	Sawdust

Gasification, pyrolysis and hydrogen potential are advanced energy conversion processes that contribute significantly to improving energy efficiency. Gasification converts carbon-containing materials into high-energy syngas with up to 90% thermal efficiency, which offers flexible energy applications such as electricity and liquid fuels. Similarly, pyrolysis, through high-efficiency conversion of biomass into bio-oil, biochar, and pyrolytic gas, provides sustainable energy solutions while minimizing energy loss in the process. Hydrogen, with its high energy density, further supports energy efficiency by reducing dependence on fossil fuels and enabling cleaner energy production through renewable sources. All of these processes play an important role in driving the transition to a cleaner and more sustainable energy system while optimizing energy use in various sectors. Here are the impacts of gasification on efficiency:

1.     High Energy Conversion Efficiency

• Gasification produces syngas with high heating value, the thermal efficiency reaches 70-90%, better than direct combustion (20-40%).

• Syngas can be processed into electricity, heat, or liquid fuel.

2.      Flue Heat Utilization (CHP)

• Using CHP technology to utilize exhaust heat increases the total efficiency to 90%, making it economical and environmentally friendly.

3.      Energy Flexibility

• Syngas can be used directly for electricity or converted into liquid fuel (methanol/DME), supporting diverse energy needs.

4.      Reduced Energy Loss

• Gasification processes wet biomass without intensive drying, reducing energy wasted during processing.

5.      Higher Power Generation Efficiency

• IGCC technology can achieve electricity efficiency of 45-55%, surpassing coal-based plants.

Pyrolysis is the process of converting organic materials (such as biomass) into high-value products through heating in the absence of oxygen. In pyrolysis, biomass is heated at high temperatures (around 400-700°C) under anaerobic conditions (without oxygen). The impact of Pyrolysis on Efficiency can be seen as follows:

1.      Direct Energy Conversion

• Pyrolysis converts biomass into bio-oil, biochar, and pyrolytic gas with an energy conversion efficiency of up to 70-80%.

• The bio-oil product has a higher energy density than the raw biomass.

2.      Utilization of By-Products

• Biochar can be used as fertilizer or carbon storage, increasing the added value of the process.

• Pyrolytic gas can be reused as fuel to support the pyrolysis process itself, reducing external energy requirements.

3.      Wet Biomass Handling

• Pyrolysis is able to process biomass with low to medium moisture content without intensive drying process, improving overall energy efficiency.

4.      Energy Transportation and Storage Efficiency

• The resulting bio-oil is easier to store and transport than raw biomass, reducing the energy required for logistics.

5.      Flexibility in Energy Generation

• Bio-oil can be directly used as fuel for power generation or further processed into transportation fuel, supporting flexibility in energy needs.

Hydrogen potential refers to the ability of hydrogen as a future energy source that can be used in various sectors to replace fossil fuels, reduce carbon emissions, and support the transition to a cleaner and more sustainable economy. The impact of Hydrogen Potential on Efficiency can be seen as follows:

1.      High Energy Efficiency in Use

• Hydrogen has a high energy value per unit mass, more efficient than fossil fuels for transportation and industrial applications.

• The process of converting hydrogen into energy (e.g. in fuel cells) yields efficiencies of up to 60%, higher than fossil fuel combustion.

2.      Use of Renewable Energy for Production

• Hydrogen can be produced through electrolysis of water using electricity from renewable sources (e.g., solar or wind power), optimizing the efficiency of clean energy use.

• The use of renewable energy for hydrogen production reduces dependence on more efficient conventional energy.

3.      Reduction of Energy Loss in Storage and Transportation

• Hydrogen in gaseous or liquid form can be stored and transported more efficiently than other energy sources, facilitating energy distribution without significant losses.

4.      Improved Energy System Efficiency

• Using hydrogen as a fuel can reduce energy waste in the transportation (e.g., hydrogen cars) and industrial sectors, providing better efficiency in energy use than gasoline or diesel-based vehicles.

5.      Integration with Renewable Energy Systems

• Hydrogen can act as a store of energy from volatile renewable sources (such as wind and solar), improving the efficiency of the overall energy system by addressing the issue of energy supply instability.

The three technologies above offer ways to reduce emissions with different approaches. Gasification is a technology that converts biomass into syngas under controlled conditions, producing pollutants such as particulates, sulfur dioxide (SO₂) and nitrogen oxides (NOₓ) in lower quantities than direct combustion. The process also prevents the release of methane (CH₄), a more potent greenhouse gas, and enables the use of syngas as a fossil fuel substitute, thereby reducing carbon emissions. In addition, gasification can be combined with carbon capture technologies (CCS) to support carbon neutrality. Pyrolysis processes biomass in the absence of oxygen, producing products such as bio-oil, biochar and pyrolytic gas with lower emissions than direct combustion. It also reduces the formation of pollutants such as SO₂ and NOₓ and prevents the release of methane from biomass decay. By-products such as biochar can be utilized for carbon storage, helping to reduce the overall carbon footprint. Meanwhile, hydrogen technology provides a low-emission solution by providing clean energy that only produces water vapor when used in fuel cells. Hydrogen can be produced through electrolysis of water using renewable energy, which avoids CO₂ emissions from burning fossil fuels. Hydrogen can also replace fossil fuels in the transportation and industrial sectors, reducing greenhouse gas emissions as well as air pollution. In addition, this technology enables the storage of volatile renewable energy, improves the integration of clean energy into the power grid, and reduces reliance on more polluting conventional energy.

There are companies that have used one of these technologies. The company Nel ASA. Nel ASA is a global company focused on hydrogen solutions, specifically in the production of green hydrogen through water electrolysis using renewable energy. This technology enables hydrogen production without carbon emissions, contributing significantly to the reduction of greenhouse gas emissions. Nel provides proton exchange membrane (PEM)-based electrolyzers and atmospheric alkaline electrolyzers, which are used in a variety of industries, including fertilizers, green steel, and cement. As such, Nel ASA supports the transition to a low-carbon economy through the provision of environmentally friendly hydrogen solutions. Nel ASA focuses on advancing green hydrogen production through electrolysis technology, which enables the transition to clean energy. They offer PEM and alkaline electrolyzers, which support various sectors such as fertilizers, green steel, and cement. The Herøya facility in Norway has a production capacity of 1 GW, making it one of the largest automated electrolyzer plants in the world. In addition, Nel is also involved in innovative projects such as offshore hydrogen production from renewable energy. They aim to increase the efficiency of hydrogen production while making it a viable alternative to fossil fuels.