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Key Questions Answered in this Section

  • What are millet cobs, and why are they considered valuable biomass feedstock?
  • How much millet is produced annually in India, and what types of millets contribute to this production?
  • What are the main characteristics of millet cobs that make them suitable for energy applications?
  • What are the current and emerging uses of millet cobs in industries and agriculture?
  • What is the seasonal availability of millet cobs across different Indian states?
  • What are the key challenges in using millet cobs as biomass feedstock?
  • How are millet cobs processed and stored for industrial applications?
  • In what forms are millet cobs used in industrial heating and power generation?
  • What types of industries are currently using millet cobs, and for what purposes?
  • What is the current annual utilization of millet cobs for biomass energy in India, and how is it expected to grow?
  • How is the price of millet cobs in loose form and as briquettes determined, and what factors influence its cost?
  • Is it possible to directly use millet cobs in boilers?

Introduction

Millet cobs, the compact cores left after de-graining millet, are gaining attention as a valuable biomass feedstock. Rich in lignocellulosic fibers, millet cobs are ideal for biofuel production, biochar, and even as a substrate for growing mushrooms or producing compost. 

Millet plants are highly resilient, often cultivated in semi-arid climates, so using their cobs doesn’t compete with essential resources like water or land for food crops. Additionally, millet cobs can serve as a low-cost, renewable material for rural heating solutions or in creating biocomposites, adding sustainability and economic value across energy, agriculture, and manufacturing. Let us look into the price, availability, and proximate analysis of millet cob briquettes and pellets, their use in boilers, and the role of transport and logistics in their efficient distribution.

Total Millet Generation in India

India produces around 15-16 million metric tonnes of millet annually, making it one of the largest producers globally. The production includes various types of millets, such as:

Millet TypeTotal Crop Production (in MTPA)Primary States of Cultivation
Pearl Millet (Bajra)9.5Rajasthan, Maharashtra, Gujarat, Uttar Pradesh
Sorghum (Jowar)4.5Maharashtra, Karnataka
Finger Millet (Ragi)1.6Karnataka, Tamil Nadu, Odisha
Small Millets0.35Various regions; include states growing foxtail, barnyard, and kodo millet
Generation of Different Kinds of Millets in India

The promotion of millets as “Nutri-cereals” by the Indian government has increased their popularity, leading to better yields and more emphasis on millet-based agriculture, particularly under initiatives like the National Food Security Mission (NFSM).

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Seasonality

Known for its drought tolerance, Bajra thrives in warm, dry climates with low annual rainfall, making it a versatile crop suited for varied agricultural practices across India.

StateSeasonPlanting Time
RajasthanSummerFebruary-May
Uttar PradeshSummerFebruary-May
GujaratSummerFebruary-May
RabiNovember-February
MaharashtraRabiNovember-February
Tamil NaduSummerJanuary-February (for high yield)
RabiOctober (first fortnight)
PunjabSummerMarch-June
Seasonality of Millet in Different States of India

Regional Availability

Regions with abundant millet cob availability can leverage this resource for use in boilers, promoting sustainable energy practices. Here are the top 5 regions in bajra production in India:

StateTotal Bajra Production (in MTPA)Key Regions of State
Rajasthan3.75Alwar, Jaipur, Jodhpur, Sikar, Nagaur, Barmer, Jaisalmer, Bikaner, Ganganagar, Jhunjhunu, Jalore, Dausa, Karauli, Bharatpur
Uttar Pradesh1.95Western UP, Agra
Haryana1.1Sims, Hisar, Karnal, Kaithal, Kurukshetra, Fatehabad, Bhiwani, Rohtak
Gujarat1Kutch, Banaskantha
Madhya Pradesh0.9Malwa
Top 5 Millet Producing States in India

Uses of Millet Cobs

Current Uses
  1. Fuel Source: Dried millet cobs are used as a low-cost, eco-friendly fuel for cooking in rural areas.
  2. Animal Feed: Ground cobs serve as an affordable, fibrous feed component for livestock, especially in regions with limited forage.
  3. Compost/Fertilizer: Millet cobs decompose readily, enriching soil with organic matter and improving moisture retention.
Emerging Uses
  1. Biochar Production: Millet cobs are converted to biochar, enhancing soil fertility and sequestering carbon.
  2. Bioplastics: The cellulose content is utilized in the development of biodegradable plastic alternatives.
  3. Construction Material: Processed millet cobs are being explored in eco-friendly building materials like particle boards and insulation

Storage of Millet Cobs

  • Moisture Control: Ensure cobs are dried to an optimal moisture level (generally below 12%) to prevent mold and spoilage during storage.
  • Ventilated Storage: Use well-ventilated storage spaces to maintain air circulation, which helps control humidity and temperature, reducing the risk of spoilage.
  • Protection from Pests: Regularly inspect for and control pests with preventive measures like physical barriers, natural repellents, or safe pest management practices.
  • Storage in Bags or Bins: Use airtight bags or bins, preferably made from breathable materials, to minimize exposure to excess moisture and pests while maintaining grain quality.
  • Proper storage ensures that millet cob briquettes and pellets maintain their quality, facilitating efficient transport and logistics to various regions.

Millet Cobs as Feedstock – Key Challenges

  • Low Energy Density: Millet cobs have a low calorific value, requiring high volumes to produce sufficient energy, which can affect cost-effectiveness in energy applications.
  • Moisture Sensitivity: Millet cobs absorb moisture easily, which can lead to mold and fermentation, impacting quality and storage life.
  • Handling and Processing: Their irregular shape and size make mechanical handling and processing difficult, leading to potential inefficiencies.
  • Ash Content: High ash levels in millet cobs can cause residue buildup in combustion systems, requiring frequent maintenance.
  • Seasonal Availability: Millet cobs are typically available only post-harvest, leading to inconsistent supply and requiring strategic storage solutions for year-round use.

Millet Cobs for Industrial Heating and Power Generation

Uses of Millet Cobs for Industrial Heating and Power Generation

Millet cobs are primarily used in industries for:

  • Biomass Boilers: They serve as a renewable fuel source for biomass boilers, providing a cleaner alternative to coal and fossil fuels.
  • Co-generation: Many industries utilize millet cobs in co-generation systems, where both heat and power are produced from the same fuel source, enhancing efficiency.
  • Pellet Production: Millet cobs can be processed into pellets, which are easier to handle and store, making them suitable for various industrial applications.
  • Industrial Heating: They are used directly in furnaces and heating systems, providing a steady and reliable heat source for processes in food processing, textiles, and ceramics.
Form in Which Millet Cobs are Used in Industries

Industries utilize millet cobs in several forms:

  • Whole Cobs: Directly burned in biomass boilers or stoves.
  • Chips: Shredded millet cobs are used for efficient combustion.
  • Pellets: Compressed millet cobs that improve handling and combustion efficiency.
  • Powder: Ground millet cobs can be used in various industrial processes, such as particleboard manufacturing.
Boilers Using Millet Cobs

Several industries have integrated millet cobs into their biomass boiler systems:

  • Food Processing Units: Facilities like rice mills and flour mills are increasingly adopting biomass boilers that utilize millet cobs for drying and heating.
  • Textile Industries: Some textile manufacturers use millet cobs for steam generation in dyeing and finishing processes.
  • Paper and Pulp Industries: Biomass boilers powered by millet cobs are being used to generate steam for various processes in paper production.
Amount of Millet Cobs Being Used by Industries for Industrial Heating

The demand for millet cobs has been steadily increasing. According to the Indian Biomass Power Association, industries are currently utilizing approximately 1.2 million tonnes of millet cobs annually for biomass heating and power generation. This figure is expected to rise as more industries recognize the benefits of using renewable biomass.

Prominent Industries Using Millet Cobs for Industrial Heating

Several prominent industries are leading the way in adopting millet cobs for industrial heating:

  • Agricultural Processing: Mills and food processing units, especially in states like Punjab, Haryana, and Maharashtra, are significant users of millet cobs.
  • Textiles: Companies in Tamil Nadu and Gujarat are incorporating millet cobs in their manufacturing processes, focusing on sustainable practices.
  • Paper Manufacturing: Paper mills in Karnataka and Andhra Pradesh are exploring millet cobs as a biomass source to enhance energy efficiency.
  • Pharmaceuticals: Some pharmaceutical companies in Maharashtra are turning to millet cobs for their energy needs, capitalizing on the renewable energy movement.

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