Biomass Boiler Testing and Selection of Suitable Biomass Fuel

In line with the trends toward decarbonization and sustainability across various sectors of life, particularly in the processing industries (manufacturing/process industries), the use of biomass boilers has become a realistic option today among boilers that utilize other renewable energy sources. Fossil-fuel-fired boilers—such as solid-fuel boilers (coal), liquid-fuel boilers (industrial diesel), and gas-fired boilers (natural gas)—must be replaced with renewable fuel boilers, namely biomass boilers. Apart from technical factors in the form of operational adjustments from previous fossil-based fuels, the suitability and availability of biomass fuels are important factors. Suitability refers to the technical aspect and availability refers to the economic aspect.

Combustion technology for biomass boilers also continues to develop so that efficiency continues to increase. From the beginning in the form of static grates to dynamic moving grates such as chain grates and reciprocating grates, even fluidized beds. And to get optimal performance, biomass fuel specifications must also match the shape, size, calorific value and dryness. If the specifications do not meet the requirements of the combustion technology in the boiler then of course the performance will not be optimal. For example, chain grates are suitable for using fuel that has a uniform size and low water content such as palm kernel shells, wood chips and wood pellets. Apart from that, biomass fuel with ash content which has a high melting point is highly preferred so that the ash does not melt and clog the chain lattice cavity.

Meanwhile, using a reciprocating grate, this system is very reliable for burning biomass with high moisture content (up to 60%), non-uniform size, and high ash content, such as empty oil palm fruit bunches (EFB), bark, and municipal solid waste (MSW). The combustion system moves back and forth periodically (like a moving staircase that moves back and forth) which functions to mechanically turn and stir the fuel. And for fluidized beds, this system has the highest thermal efficiency (>89%) and is very suitable for biomass with very small size (powder/dust), low calorific value, or fluctuating chemical content such as rice husks, sawdust, and coffee grounds. The biomass particle size must be maintained within certain limits so that it can float and fluidize perfectly with the sand bed media. The ideal particle size for a fluidized bed boiler (FBC) generally ranges from 0.1 mm to 10 mm (maximum 30–50 mm for certain components), depending on the specific type of technology used.

As a country located on the equator with a tropical climate, Indonesia is a biomass paradise in the world; read more here. A wide variety of biomass fuels in large volumes can be sourced in Indonesia. The most readily available biomass fuels in Indonesia today are wood chips, palm kernel shells, and wood pellets. Wood briquettes are also available but in limited quantities. Choosing the right biomass fuel will ensure optimal boiler performance, but of course, the economic factors for each metric ton of high-pressure steam produced are equally important. 

Ideally, biomass fuel is available in large quantities, ensuring affordability and high quality. The price of biomass fuel is influenced by various factors, including availability, location, logistics infrastructure, and transportation costs. Furthermore, if the biomass fuel undergoes processing, such as wood pellets and briquettes, production costs also contribute. Palm kernel shells for industrial boiler use in Indonesia require almost no processing; they are simply collected from palm oil mills or CPO mills, which produce waste in the form of palm kernel shells (PKS).

There is a case study regarding the selection of this biomass fuel involving a multinational company. In a certain country, the company’s boilers operate using wood briquettes—specifically, industrial briquettes produced by a mechanical press. This approach was also planned for the company’s plant in Indonesia. However, because producers of wood briquettes are still very scarce in Indonesia—making it impossible to secure a supply—the company ultimately conducted various experiments and trials with different types of biomass fuels and now operates its boilers using wood pellets. Thus, in addition to technical factors, economic factors are also crucial for ensuring optimal and sustainable biomass boiler operations. The trial phase is a critical step in achieving these conditions. 

Not Only Reduce Steam Cost, but Also Reduce Water Treatment Cost for Boiler Feed Water and Even Also Increase Revenue with EFB Cogeneration

Even though biomass waste is abundant in palm oil mills, the use of efficient boilers is also needed. Efficient use of biomass waste according to the type/specifications will also provide additional benefits for palm oil mills. The longer the biomass waste, the more diverse its uses, ideally even zero waste. Apart from mesocarp fiber which is usually used 100% and added with a number of palm kernel shells (PKS) and sometimes also a few empty palm fruit bunches (EFB), an efficient boiler will optimize the type and amount of biomass. For example, PKS as a commodity that can be sold are used as little as possible for boiler fuel, so that more can be sold which increases the profits of the palm oil mill.

Photo taken from here

Is a utility business like buying steam from another company needed? Utility businesses like selling steam, heat, or electricity are indeed starting to emerge; for more details, read here. Certain companies are greatly helped and receive utility products according to their wishes. They do not want the hassle of operating a boiler, including sourcing its fuel. However, for palm oil mills that in their operations produce a lot of biomass waste that can be used as fuel, it is more practical and efficient to operate their own boiler. And this has been a common practice in palm oil mills for a long time. Therefore, cooperating with a utility company to obtain steam and electricity is not an effective solution. The effective solution is the use of an efficient boiler as explained above.

Apart from that, regarding boiler feed water to increase efficiency or reduce costs and be environmentally friendly, AOP (Advanced Oxidation Process) technology, namely an electrochemical device, is used. With this method, apart from not using chemicals so it is environmentally friendly, it will also increase the service life of the RO (reverse osmosis) membrane which is the heart of the water treatment unit. Not only will the RO membrane have a longer service life, but also the activated carbon filter and ion exchange resin, which are stages of water treatment. Apart from being environmentally friendly, this technology is also more in line with the sustainability mission.

And regarding boiler operations, even to increase the volume of PKS that can be sold, cogeneration of empty palm fruit bunches (EFB) can be carried out. In this way, the EFB, which have been waste biomass which pollutes the environment and which most palm oil mills have not yet processed, are then burned to produce heat and potassium ash. The potassium content above 30% in the ash will make quality fertilizer that can be sold or used in your own plantation. Meanwhile, the heat from burning EFB is used as additional energy for the boiler (cogeneration). In this way, 100% of PKS can be sold and even exported.

If the use of PKS for boiler fuel reaches 50% then using this technology means that 50% of the  PKS can be recovered or taken back or 100% of the PKS can be sold or even exported. For example, a palm oil mill under normal conditions can sell 2,000 tons of PKS/month, then by using this technology the palm oil mill can sell 4,000 tons of PKS/month. Of course the increase in PKS supply volume is very significant to increase income, for more details read here. 

OPT Briquette and EFB Briquette for Medium Capacity Industrial Biomass Boiler Consumption

The growing utility business, specifically the provision of steam and electricity for renewable energy-based industries, particularly biomass, has led to a growing need for biomass fuel. This also applies to industries using their utility units to produce steam and electricity using biomass fuel. In addition to biomass fuel, water quality, the raw material for steam and electricity production (using steam turbines), is also crucial and must be considered. Good water quality will ensure optimum steam and electricity production performance, and the longevity of equipment (boilers, heat exchangers, steam turbines, and cooling towers), and vice versa. Good water quality is like healthy blood for our bodies, enabling all organs to function optimally.

Palm oil industry solid waste is a potential raw material for biomass fuel. This solid waste is empty fruit bunches (EFB) and oil palm trunks (OPT). EFB is produced from palm oil mill operations with a percentage of approximately 22% of fresh fruit bunches (FFB), while oil palm trunk waste is produced from replanting programs of oil palm plantations, which are also very abundant. For more details, read here. Utilizing both of these biomass wastes for the production of biomass fuel, especially biomass briquettes, would be very good. But why are they processed into briquettes?

The advantage of briquettes over pellets, aside from technical advantages, lies in their scale. Briquette production requires a looser particle size and lower moisture content. Energy consumption per ton of briquette production is also lower than that of pellet production. This makes EFB briquette and OPT briquette production more suitable for a palm oil mill serving medium-sized industries. A palm oil mill with a capacity of 45 tons/hour of FFB will produce approximately 10 tons/hour of EFB. With a 20-hour daily operation, approximately 200 tons will be produced per day. With a moisture content of approximately 60%, this means that after drying, approximately 100 tons/day (10% moisture content) will be produced, or 2,500 tons/month.

Likewise, when using oil palm trunk (OPT) waste as raw material, it depends on the ratio or percentage of land replanted each year. Replanting itself is an effort to continuously maintain the productivity of the oil palm plantation itself, in addition to the use of superior seeds and intensification. For more details, read here. For example, with a land area of ​​10,000 hectares and each year replanting 5% of the land, or 500 hectares. With an average of 125 trees per hectare of oil palm plantation and each tree having an average dry weight of 0.4 tons, then per hectare obtained 50 tons of dry weight of biomass. With an area of ​​500 hectares, this means 25,000 dry palm trunk biomass (10% moisture content) each year or can be processed into OPT briquettes with a capacity of around 2,000 tons/month.

Biomass boilers, used for producing biomass briquettes (EFB briquettes/OPT briquettes), can utilize various combustion technologies, such as moving grates, stokers, reciprocating grates, and so on. The choice depends on the cost or price of the boiler and its efficiency. In addition to biomass fuel, to align with decarbonization and sustainability programs, water for boiler operation, including boiler feedwater and cooling water for heat exchangers (heat exchangers/condensers), is crucial. This is likened to blood for the human body; healthy blood ensures optimal function. If impure blood circulates throughout the body, for example due to kidney failure, organs will automatically be damaged, and a person will soon die.

To maintain water quality for steam production through a boiler, boiler feedwater/demin water must strictly comply with the boiler's operational specifications. The higher the boiler pressure, the higher the water quality or purer the water required. If the steam is used for electricity production, after the steam drives the turbine, it needs to be condensed in a heat exchanger (condenser) so that it changes phase back to liquid and enters the boiler again. This heat exchanger requires cooling water that is continuously used repeatedly, thus requiring a cooling tower. Not only does the boiler feedwater/demin water need to meet the required technical specifications, but so does the cooling water for this condenser. With water volumes circulating up to thousands of tons per hour and operating 24 hours a day (the same as boiler operations) in the cooling tower, a number of water problems in the cooling tower need to be addressed effectively and efficiently. A number of water problems that occur in cooling towers can be read here.

In addition to electricity production, steam is also used for processes within a specific plant. If the steam is then condensed, then liquid, and returned to the boiler, this requires a cooling tower, just as in electricity production. Efficient and environmentally friendly water treatment technology, which eliminates secondary pollution and is easy to operate and maintain, aligns with the vision of decarbonization and sustainability. This vision of decarbonization and sustainability will be even more optimal or ideal for utility units, namely the use of biomass-based renewable energy and environmentally friendly water treatment technology. 

Energy Sources for Data Centers: Between Growth and Sustainability and the Role of Bioenergy

Data centers are physical facilities that house computer systems and related infrastructure, such as servers and storage, used to store and process data. They form the foundation of a nation's computing power and are a core dependency in building large-scale Artificial Intelligence (AI). AI data centers, in particular, are particularly energy-intensive. According to the International Energy Agency (IEA), a typical AI data center currently uses as much energy as 100,000 households, while large AI centers currently consume about 20 times that amount (2 million households).

The computing power needed to support AI growth is also doubling approximately every 100 days. For example, Malaysia, it is not surprising that data center energy consumption in Malaysia is projected to soar to more than 5,000 MW by 2035, which is 40 percent of Peninsular Malaysia's current power capacity, or 11.1 percent of Malaysia's projected power capacity in 2035. Meanwhile, in Indonesia. Meanwhile, the projection of data center electricity consumption in Indonesia has increased significantly, predicted to reach 5,200 MW in 2034 and could even reach 12,000 MW in 2033. And the current capacity in 2025 is only around 274 MW and with a predicted growth of 16.8% per year, it can reach the target of >2,000 MW in 2029.

There are at least two main drivers of growth in the data center industry. First, demand-side factors include the growth of cloud computing and AI, along with the increasing global demand for data storage and processing capacity for everyday tasks like social networking, e-commerce, and data storage. Second, supply-side factors include the availability of resources such as electricity and water, fiber optic connectivity, and land availability.

In the growing data center industry, high or wasteful energy consumption has contributed to rising electricity prices for residents and small businesses. Each country should learn from these case studies as they strive to strike a balance between growth and sustainability. For example, in Georgia, the fastest-growing data center market in the country, Georgia Power reports that 80 percent of the projected 8,200 MW increase in energy demand by 2030 is related to planned data centers opening in the state. To address the increased demand, base electricity rates have been raised and new nuclear power plant (NPP) are under construction.

Georgia is an attractive market for data centers, given its relatively low electricity prices, with industrial electricity rates about 42 percent below the US national average. Significant tax relief was also promised, with at least $163 million in state collections eliminated and local sales tax annually starting in 2022. However, starting in 2023, the average Georgia Power residential customer will pay $43 more per month following a base rate increase. To address this challenge, a Senate bill was introduced to protect residential and commercial customers from higher electricity bills due to the utility's significant investment in AI-powered energy needs.

Efforts to address the increasing energy demand for data centers while reducing their environmental impact are necessary. Typical approaches include optimizing Power Use Effectiveness (PUE) and related metrics, as well as shifting to renewable energy. The use of renewable energy for data centers remains limited, or even at a small capacity of less than 5%. Renewable energy sources still prioritize solar and intermittent wind.

Industry participants also state that the intermittent nature of solar energy (at least without a well-developed battery storage system) does not make it an ideal energy source for data centers, given the need to keep data centers running 24/7. With limited solar generating capacity, data centers often rely on backup diesel generators. While renewable diesel (biodiesel and green diesel) is an available option, there are currently no regulations encouraging this transition.

Biomass as an energy source, or bioenergy, for data centers is still very limited. This biomass can be used directly in biomass power plants, where the CFB type is very common, or through co-firing in coal-fired power plants. Furthermore, biomass can be utilized as an energy source and biochar production through pyrolysis technology, as is the case with this US company. The syngas from pyrolysis serves as a carbon-neutral energy source, and biochar is the primary product for carbon capture and sequestration (CCS), resulting in carbon-negative operations. 

Utility Business for Palm Oil Mills

When the priority is to obtain the maximum profit, good environmental management and ease, efficiency and stability of production as an option, then utility matters at the palm oil mill may be collaborated with other parties. This specialization becomes important because of the priority choices above. The utility problems in question are electricity and steam. Electricity is produced from a steam turbine and steam is produced from a boiler. High pressure steam enters the steam turbine to drive a generator and produce electricity and low pressure steam output from the steam turbine is used for the fresh fruth bunch (FFB) sterilization process. Water treatment for boiler feed is also part of the utility problem, as well as for boiler operations to produce output in the form of electricity and steam.

Regarding cooperation or business models, palm oil mills can pay for the electricity and steam they receive. But because the fuel or energy to produce electricity and steam comes from palm oil mills, of course the price is cheaper. If currently almost all palm oil mills use their boiler fuel from mesocarp fiber and palm kernel shell (PKS), then with this specialization it is possible for palm fiber (mesocarp fiber) and empty palm fruit bunches (EFB) to be used as fuel or energy sources while palm kernel shells (PKS) can 100% sold and even exported. Palm kernel shells (PKS) as biomass fuel can be sold directly and are in great demand, and are also the main competitor for wood pellets in the global biomass fuel market.

Under these conditions, there are efforts to increase the efficiency of utility production such as steam and electricity as optimally as possible, not only combustion technology with static grates, moving grates, reciprocating grates to fluidized beds, but it is even possible to use pyrolysis. EFB or empty palm fruit bunches, which were previously unprocessed and were an environmental problem, can become a potential energy source so that 100% of the palm kernel shells / PKS from palm oil mills can be commercialized/sold. And even if the utility provider uses pyrolysis, biochar will also be obtained. Biochar provides many benefits related to soil fertility and climate.