The use of biomass in boilers to support SEA’s renewable energy goals

Biomass-based solutions leveraging digital capabilities to support Thailand 4.0 vision

Southeast Asia’s Industrial Growth & Thailand’s Renewable Imperative

Southeast Asia continues to emerge as a rising industrial and manufacturing cluster, and is now under increasing pressure to align growth with sustainability. Thailand, in particular, has positioned itself as a frontrunner in balancing economic competitiveness with low-carbon ambitions. Central to that is its Thailand 4.0 / smart-industry / decarbonisation agenda, which hinges on energy intensity reduction, renewable energy uptake, and digitalisation.

Thailand’s Energy Efficiency Plan 2018–2037 (EEP 2018) sets a goal of reducing energy intensity by 30 % by 2037 (compared to the 2010 baseline).

That corresponds to approximately 49,064 ktoe energy savings across sectors, with the industrial sector being a major contributor. (APEC)

The country is also integrating renewable energy goals via its Alternative Energy 

Development Plan (AEDP), aiming to increase the non-fossil energy share in consumption/power mix by 2037. (Trade.gov)

Thailand has further committed to carbon neutrality by 2050, and net-zero greenhouse-gas emissions by 2065, under its long-term strategy to the UNFCCC. (1p5ndc-pathways.climateanalytics.org)

These policy frameworks provide both the mandate and the incentive for industries to reduce energy-use per unit output (i.e. energy intensity), switch to cleaner fuels or more efficient equipment, and embrace digital / smart-control systems to optimise operations.

Process / Thermal-Intensive Industries & the Role of Biomass

Industries in Thailand that rely heavily on heat/steam/thermal processes – such as palm oil, agro-processing, pulp & paper, food processing, textiles, base materials (ceramics/glass), and chemicals/refining – constitute a significant portion of energy demand. Because of their dependence on thermal energy, they become levers for decarbonisation via fuel substitution and efficiency upgrades.

Carbon Neutrality and Environmental Impact

Biomass is considered carbon-neutral in lifecycle terms: the CO₂ emitted during combustion was earlier captured by the biomass during growth. When not utilised as fuel, the natural decomposition and decay of biomass produce methane (CH₄), a greenhouse gas nearly 28 times more potent than carbon dioxide over a 100-year period (IPCC, AR5, 2013). 

Controlled combustion of biomass for energy thus prevents the uncontrolled release of methane and provides a cleaner alternative to open burning or decay, effectively reducing overall greenhouse-gas impact.

Availability, Energy Security and Policy Alignment

Thailand’s agricultural and agro-processing economy ensures abundant availability of residues such as rice husks, bagasse, wood and plantation by-products, and palm residues.

Using biomass enhances energy security by reducing dependence on imported or more costly fossil fuels, while aligning with governmental incentives and regulatory direction under the AEDP and BOI frameworks for renewable and clean energy adoption.

Given these drivers, biomass-fired boilers and heaters are increasingly seen as a key lever to decarbonise Thailand’s thermal-process industries.

Technical Challenges of Biomass Combustion

However, switching to biomass is not as simple. Biomass as a fuel brings several combustion challenges:

• Low Calorific Values and Bulk Density: Biomass fuels typically have lower calorific values and bulk densities compared to fossil fuels. This means larger volumes of biomass are needed to generate the same amount of energy, causing difficulty in transportation, storage, handling, and combustion.
• High Moisture Content: Biomass often contains high moisture levels, impacting its calorific value and combustion stability. Moisture content can range from as low as 10% to as high as 60%.
• Variation in fuel characteristics: A Huge variation in bulk density, calorific value, and moisture content is observed in biomass. The bulk density of biomass fuels ranges from as low as 30 Kg/m3 for rice straw to 500 Kg/m3 for biomass pellets.
• Non-Uniform Size: Variations in biomass fuel size present challenges in handling and achieving efficient combustion.
• Seasonal variation in Biomass availability: Fuel sourcing can be challenging due to the inconsistency in biomass availability throughout the year. This leads to significant variation in fuel characteristics and emphasises the need for fuel flexibility in boiler design.

Fouling characteristics of Biomass ash: The majority of biomass is rich in alkali content with low ash-softening temperature, causing problems like clinker formation, slagging, and fouling. This leads to higher cleaning frequency and reduced equipment uptime compared to fossil fuels.

Evolution of Combustion / Boiler Technologies for Biomass

Over the decades, combustion technology has evolved to better handle difficult fuels like biomass. Some of the key technological types include:

• Stationary grate: Simple fixed grate design, suited for small / low-throughput or uniform fuel feeds. Limited flexibility for variable moisture/feed size.
• Chain-grate systems: Moving-grate / conveyor-like design that allows continuous fuel travel across burning zones, better control of dwell time and air staging.
• Fluidised-bed systems: By fluidising fuel particles with air (or inert bed medium), these designs achieve better mixing, temperature uniformity, and toleration of lower-grade or high-ash fuels. They also help reduce localised overheating or flame-front instability.
• Travelling-grate: Similar in concept to chain-grate but with more robust design /segmentation with spreader stoker design, increasing fuel flexibility.
• Reciprocating grates: An inclined grate with alternating stationary and moving blocks with reciprocating action, ensuring continuous and controlled fuel movement through various combustion zones for achieving better fuel mixing and uniform combustion, while accommodating a wide range of biomass fuels with varying densities, calorific values, moisture, and fouling characteristics.

Each design option has trade-offs: capital cost, maintenance requirement, turndown (partial load) performance, fuel flexibility, emissions performance (especially CO, volatile organic compounds, particulate), and control complexity/automation.

Selecting the right boiler/heater architecture is fundamental to successfully deploying biomass combustion in industrial settings.

Integrated Energy-Plant Approach 

Rather than offering isolated boilers/heaters, a more strategic approach is the Integrated Energy-Plant concept – centralised combustion core with multiple heat-outputs (e.g. steam, thermic-fluid heating, hot-gas streams, or combinations thereof), custom-engineered to a site’s industrial process profile. Such systems deliver operational advantages:

• Multiple heat outputs from one combustor improve thermal efficiency (using waste heat streams), offer a lower footprint, and simplify operations/maintenance.
• Custom configuration ensures matching to the site’s steam-pressure / temperature / flow-profile, thermic-fluid temperature/flow, or hot-gas needs (for drying, kilns, or direct-heat processes).

Modular or scalable design allows capacity matching, staged operation, or retrofit-ready upgrades as site demand changes.

Emission Control Requirements for Thailand’s Sustainable Growth

Biomass-based heating systems must also comply with Thailand’s air-emissions standards. For example, Standards B.E. 2566 (2023) imposes emission limits for biomass-fired power/combustion plants:

• SO₂ ≤ 30 mg/m³
• NOₓ ≤ 200 mg/m³
• PM ≤ 90 mg/m³ (IEA)

Meeting these requires robust emission-control equipment:

• Electrostatic Precipitators (ESP)
• Electro-cyclones or pre-cyclone stage separators
• Fabric filters / bag-type filters (where appropriate)
• Multi-stage filtration (cyclone + ESP/bag filter combination)
• Possibly scrubbers or acid-gas controls (depending on fuel contaminants), especially where chlorine / volatile alkali content is involved

Beyond hardware, continuous monitoring, smart control of combustion parameters (air-flow, temperature, feed rate) and scheduled maintenance are essential to maintain compliance, efficiency, and reliability.

Complementary Decarbonisation Levers: Waste-to-Energy & Electric Heating

While biomass combustion is a leading near-term lever for decarbonising industrial heat in 

Thailand is not the only option. Other pathways include:

• Waste-to-Energy (WtE) – converting municipal solid waste / industrial/agricultural waste streams into thermal or electrical energy. Such systems help reduce landfill use or uncontrolled burning, and can provide either steam, heat, or power to industrial processes.
• Electric-heating solutions – technologies such as electric steam generators, electric heaters. When powered by renewable electricity (either on-site solar/wind or via green-power procurement), their carbon footprint can approach zero. These may suit low- or medium-temperature applications, or where electrified infrastructure is available and load-flexible.

Including these levers alongside biomass offers industries a diversified, resilient decarbonisation strategy.

Digitalisation and IIoT for Performance Optimisation

Under Thailand 4.0, digitalisation and Industrial Internet of Things (IIoT) technologies play a vital role in enabling data-driven operations.

IIoT-enabled remote monitoring and diagnostics continuously track combustion performance, fuel-feed irregularities, temperature fluctuations, and emission levels. By detecting anomalies early, these systems support predictive maintenance, reduce downtime, and improve reliability – ensuring that biomass and other heating systems perform optimally over time.

Smart AI Controls for Energy Optimisation

Smart AI-based controls bring intelligence and adaptability to industrial heating operations. By analysing real-time data and learning from process patterns, ambient conditions, and boiler health, these systems predict load fluctuations and optimise fuel and energy use. They help maintain steady output while reducing operational costs and unplanned downtime. Over time, continuous learning enhances accuracy, enabling more efficient and reliable plant performance.

Conclusion & Thermax-Led Solutions

With decades of experience in industrial heating and energy systems, Thermax continues to enable global industries to move towards cleaner, smarter, and more efficient operations. Its expertise spans advanced biomass combustion, integrated energy plants, waste-to-energy solutions, and intelligent digital platforms that align closely with Thailand’s 4.0 vision for decarbonisation, energy intensity reduction, and digital transformation.

Through deep process understanding, engineering innovation, and on-ground presence, Thermax partners with industries to realise their renewable energy goals and operational excellence – a reflection of its philosophy: Global expertise, local commitment.

Presenters:

Dinesh Badgandi
Head International Business Group – Industrial Products
Thermax Group

Anil Misher
Sales Manager, Process Heating,
Thermax Group

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