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From Rice Husks to Napier Grass—The Untapped Potential of Agricultural Waste

While traditional biomass sources like wood often steal the spotlight, the potential of agricultural residual waste in renewable energy generation is slowly gaining recognition. These materials, often considered waste, can provide an eco-friendly alternative for energy production. In this article, we’ll delve deeper into the world of agro-residual waste, focusing on rice husks, bagasse, and coconut husks, as well as rapid-growing bio-crops like Napier grass. We’ll examine how they stack up in terms of both productivity and environmental impact.

Rice husk from Berde Kaway, a pellet production factory in Sariaya


  • Productivity: High
  • Eco-Friendly: Moderate

Wood remains the most commonly used type of biomass. Wood chips or pellets are known for high energy output and are often used in converted coal boilers. However, the source of the wood is critical. If it comes from sustainably managed forests, then it’s a much greener option.

Rice Husks

  • Productivity: Moderate
  • Eco-Friendly: High

Rice husks are the hard-protective coatings around grains of rice. Traditionally, they have been treated as a waste material, but they contain a significant amount of lignin, a compound that burns well. While not as energy-dense as wood, rice husks are abundant in rice-growing regions and can be a sustainable alternative when sourced responsibly.


  • Productivity: Moderate
  • Eco-Friendly: High

Bagasse is the fibrous residue left after extracting sugarcane juice. Like rice husks, bagasse has moderate energy density but scores high on the sustainability front. Using bagasse as biomass helps sugar mills become more self-sufficient in energy, as they can use their waste to power their operations.

Coconut Husks

  • Productivity: Moderate
  • Eco-Friendly: High

The fibrous outer shell of coconuts, usually discarded or used in low-value products, can be repurposed as a biomass source. Though they don’t offer the same energy output as some other materials, their abundant availability in tropical regions makes them an attractive, eco-friendly option.

Accumulation of discarded coconut husk

Napier Grass and Other Rapid-Growing Crops

  • Productivity: High
  • Eco-Friendly: Moderate to High

Napier grass, also known as “elephant grass,” grows rapidly and can yield high amounts of biomass in a short period. The fast growth allows it to absorb significant amounts of CO2, making it a more eco-friendly option compared to fossil fuels. Other similar high-yield, fast-growing crops include switchgrass and miscanthus. However, the environmental impact of these crops can vary depending on factors like water usage and the need for fertilizers.

Napier in BRED nursery

Balancing Act: Productivity vs. Sustainability

The use of agricultural waste for biomass represents a win-win situation: it not only provides a sustainable way to dispose of what would otherwise be waste but also offers a renewable source of energy. However, productivity and eco-friendliness often need to be balanced. For instance, while Napier grass is highly productive, its cultivation may require more inputs like water and fertilizer, potentially impacting its overall sustainability.


Agricultural residual wastes and rapid-growing bio-crops offer exciting possibilities in the field of renewable energy. Their dual advantage lies in their moderate to high productivity and excellent sustainability credentials. By incorporating these materials into our biomass portfolios, we’re not only reducing waste but also making strides toward a more sustainable and energy-efficient future. Therefore, as industries consider the shift from traditional fossil fuels to greener options, these agricultural by-products and rapid-growing crops hold immense untapped potential.

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Maxime Droit CEO at REURASIA Energy Solutions Biomasss Construction & Commissioning Expert

is dedicating its time to serve the local community's best interest by developing and supporting sustainable renewable energy projects in the Philippines.