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The agricultural sector is at the forefront of addressing the global challenges of food security, environmental sustainability, and climate resilience. In this context, renewable energy technologies are emerging as pivotal components in transforming traditional farming systems into sustainable, energy-efficient, and resilient agri-food systems. This practical manual on “Renewable Energy Solutions in Agriculture” has been designed to serve as an academic and experiential resource for Agricultural students. It brings together scientifically validated methods and hands-on exercises that aims to familiarize students with the application and integration of biomass energy, biogas generation, ethanol production, biomass briquetting, solar thermal and photovoltaic systems in the agricultural landscape. The manual is structured into eleven chapters and presents a multidisciplinary approach, reflecting the intersection of agricultural engineering, energy sciences, environmental conservation, and sustainable rural development. The manual aims to not only impart technical skills and procedural knowledge but also to inspire critical thinking on issues such as energy security, carbon neutrality, and ecological impacts of agro-industrial energy consumption. The contents align with the Sustainable Development Goals (SDGs), particularly those related to affordable and clean energy (SDG 7), climate action (SDG 13), and responsible consumption and production (SDG 12). Emphasis is placed on the need for both public and private sector innovation in promoting sustainable energy solutions that are accessible, farmer-friendly, and environmentally viable. It is our belief that science-based innovation in renewable energy must balance productivity with sustainability. While technologies such as biomass gasification, ethanol fermentation, and solar water heating enhance efficiency and reduce reliance on fossil fuels, their deployment must be guided by principles of ecological stewardship and equity. This manual is a modest effort in that direction. The students, educators, and practitioners engaging with this manual are encouraged to explore, experiment, and adapt these renewable technologies to local agricultural contexts, thereby contributing to a more resilient and energysecure future for Indian agriculture.

The Renewable energy (also called green energy) is generally defined as energy that comes from resources which are naturally replenished on a human timescale. In other words, Renewable energy is energy derived from natural sources that are replenished at a higher rate than they are consumed. The most widely used renewable energy types are solar energy, wind energy,biomass energy, and hydroenergy. India has made significant progress in the renewable energy sector, with renewable energy accounting for 43.12% of the country’s total installed power generation capacity. Globally, India ranks 4th in overall renewable energy capacity, 4th in wind power with 46.65 GW, and 5th in solar photovoltaic power with 85.47 GW. The country has surpassed 200 GW of non-fossil fuel energy capacity which includes 85.47 GW of solar power, 46.93 GW of large hydropower, 46.66 GW of wind power, 10.95 GW of biopower, 5.00 GW of small hydropower, and 0.60 GW of waste-to-energy capacity. Presently India has set ambitious renewable energy targets. By 2030, the country aims to achieve 500 GW of non-fossil fuel energy capacity and meet at least 50% of its total energy requirements through renewable sources. These efforts position India as a global leader in the transition towards sustainable and clean energy. In recent years, India’s renewable energy capacity has grown rapidly. As per the Ministry of New and Renewable Energy (MNRE, 2025), the country’s total installed renewable energy capacity (excluding large hydro) reached 220.10 GW by March 2025. When large hydro and nuclear power are included, the non-fossil fuel capacity has crossed 242.8 GW, representing over 50 percent of India’s total

Proximate Analysis of Biomass Objective To determine the key compositional parameters of biomass, including moisture content, volatile matter, ash content, and fixed carbon, using standardized analytical procedures. Principle Proximate analysis of biomass is a standardized method used to determine the basic compositional components of biomass materials. It provides essential information about fuel quality and conversion characteristics. Biomass can serve as an energy source either directly through combustion or indirectly through conversion into gaseous, liquid, or solid fuels for more efficient utilization. These transformations occur through thermochemical processes (combustion, gasification, and pyrolysis) and biochemical processes (anaerobic digestion and fermentation). Common biomass materials such as agricultural residues, cattle dung, poultry litter, and paddy straw are analyzed for parameters including total solids (TS), volatile solids (VS), ash content, total organic carbon (TOC), moisture content, and total sugars. These parameters are typically estimated using AOAC (2000) and other standard protocol. Requirements Biomass samples (such as agricultural residues, cattle dung, poultry litter, paddy straw and others materials from living organisms but now dead), silica crucible, hot air oven, desiccator, muffle furnace, weighing balance, 5% Phenol, concentrated H2SO4, UV-VIS spectrophotometer, vortex mixer, glassware like beaker and test tubes

Objective To determine the chemical composition of biomass in terms of cellulose, hemicellulose, lignin, and silica content using standard detergent fiber analysis and acid digestion techniques. Principle Chemical analysis of biomass helps in evaluating its structural and compositional characteristics, which influence its thermal behavior, degradation properties, and suitability for bioenergy applications. Biomass primarily consists of cellulose, hemicellulose, lignin, and pentosans, each playing a distinct role in the structure and energy potential of plant material: Cellulose – A linear polymer of ß-D-glucose units linked by ß-(1?4) glycosidic bonds. It provides tensile strength and rigidity to plant cell walls and serves as the main carbohydrate source in biomass. Hemicellulose – A heterogeneous branched polymer composed of pentoses (xylose, arabinose) and hexoses (mannose, glucose, galactose). It acts as a matrix surrounding cellulose microfibrils, providing flexibility and binding lignin and cellulose together. Lignin – A complex three-dimensional polymer made up of phenylpropane units. It is highly resistant to microbial degradation, provides compressive strength, and acts as a natural binder in plant tissues. Pentosans – Polymers of five-carbon sugars that contribute to carbohydrate storage and structural integrity.

The de    e plant growth, biomass composition, and energy potential. (a) Nitrogen Determination by Kjeldahl Method Theory The Kjeldahl method is one of the most reliable and widely accepted procedures for determining organic nitrogen in biomass samples. It involves the conversion of nitrogen compounds into ammonium sulfate through digestion with concentrated sulfuric acid and a catalyst. The resulting ammonia is then distilled and quantified by titration. This method measures total nitrogen, excluding nitrate and nitrite forms, and is used extensively in plant, feed, and biomass analysis. The process involves three major steps: Digestion Organic nitrogen in the sample is converted to ammonium sulfate by boiling with concentrated sulfuric acid and a catalyst mixture (usually potassium sulfate and copper sulfate) Organic-N+H2SO4?(NH4)2SO4+CO2+H2O Distillation The digested sample is made alkaline with sodium hydroxide, releasing ammonia gas, which is distilled and absorbed in a known volume of standard acid.

Introduction A biogas plant is an engineered system designed to generate biogas through the anaerobic digestion of organic materials rich in cellulose, such as cow dung, agricultural residues, poultry waste, and other biodegradable biomass. In the absence of oxygen, microorganisms decompose these materials, producing a mixture of methane (CH4), carbon dioxide (CO2), and traces of hydrogen sulfide (H2S). This biogas can be utilized as a renewable energy source for cooking, heating, and power generation. In India, cow dung has traditionally served as the primary substrate, and such systems were popularly known as Gobar Gas Plants. The early designs were promoted by the Khadi and Village Industries Commission (KVIC) Components of a Biogas Plants A typical biogas plant consists of the following major components: • Foundation: Provides structural support to the digester and gas holder. • Digester (Fermentation Tank): The main chamber where anaerobic digestion occurs. • Gas Holder (Masonry Dome or Drum): Collects and stores the biogas produced. • Mixing Tank: Used to prepare the slurry by mixing feedstock with water (commonly 1:1 ratio). • Inlet Chamber/Pipe: Feeds the prepared slurry into the digester

A biomass gasifier is an advanced device designed to convert solid biomass materials-such as wood chips, crop residues, saw-dust, coconut shells, and other organic matter-into a combustible gas mixture known as producer gas. The conversion process, known as gasification, is a thermo-chemical process that takes place in a controlled environment with limited oxygen. Unlike complete combustion, gasification allows only partial oxidation of biomass, producing a gas rich in carbon monoxide (CO), hydrogen (H2), methane (CH4), and nitrogen (N2). This gas mixture can be used as a fuel for internal combustion engines, power generation, cooking, or industrial heating applications. Principle of Gasification Gasification involves a sequence of four key thermo-chemical reactions within the reactor, occurring at temperatures ranging from 800–1000°C: 1. Drying Zone: Moisture present in the biomass is evaporated due to the rising heat. H2O (liquid) ? H2O (vapor) 2. Pyrolysis Zone: Biomass decomposes in the absence of oxygen to form volatile gases, tar, and solid char. Biomass ? Char + Volatile gases + Tar 3. Oxidation Zone: A small amount of air or oxygen is introduced to partially combust the biomass, generating heat to sustain the process.

Biomass briquetting is the process of compressing loose and low-density biomass materials such as sawdust, agricultural residues, and forest waste into high-density, solid fuel blocks called briquettes. The process involves mechanical compression under high pressure using machines like piston presses, screw extruders, or hydraulic presses, depending on the technology used. The main purpose of briquetting is to increase the density of biomass to improve its combustion properties, handling, transportation, and storage efficiency. In most modern systems, briquetting is done without the use of binders, as natural lignin present in the biomass acts as a binding agent under pressure and heat. Importance of Biomass Briquetting Biomass briquetting holds immense environmental, economic, and social importance. 1. Environmental Protection • Briquetting reduces deforestation by providing an alternative to firewood and charcoal. • It minimizes air pollution by producing cleaner-burning fuel with lower particulate emissions and sulfur content. • The process helps in carbon sequestration by ensuring the sustainable use of biomass. 2. Waste Management • Agricultural residues like rice husk, sugarcane bagasse, cotton stalks, and sawdust, which otherwise cause disposal problems, are effectively utilized.

Biogas typically comprises 60-65% methane (CH4), 35-40% carbon dioxide (CO2), and 0.5-1.0% hydrogen sulfide (H2S), along with traces of water vapor. It is approximately 20% lighter than air and has an ignition temperature of 650-750°C. The calorific value of raw biogas is around 20 MJ/m³ (4,713 kcal/m³). Unlike Liquefied Petroleum Gas (LPG), biogas cannot be converted into a liquid state under normal temperature and pressure. The critical temperature for methane liquefaction is -82.1°C at a pressure of 4.71 MPa, making liquefaction complex and energy-intensive. However, biogas can be upgraded by removing impurities like CO2 and H2S and compressing it into cylinders for use in three-wheelers, cars, pickup vans, or stationary engines at remote locations. Since Compressed Natural Gas (CNG) technology is already wellestablished, upgraded biogas (also called biomethane) which has similar composition and energy content can serve as a direct substitute for CNG in all its applications. The calorific value of upgraded biogas (with CO2 removed) increases to around 34 MJ/m³, compared to 20 MJ/m³ for raw biogas. Techniques for Biogas Purification To enrich biogas and increase its methane content, various purification methods are employed: 1. Water Scrubbing This physical absorption process involves pressurizing biogas and feeding it into the bottom of a packed column, while water is introduced at the top. The CO2 and H2S dissolve into the water as it flows downward, while methane rises and is collected. The water used can

    In recent years, the global demand for renewable and sustainable energy sources has led to increased interest in biogas production from agricultural residues and lignocellulosic biomass. Among these, paddy straw an abundant agricultural by-product—has gained attention as a potential substrate for anaerobic digestion and biofuel generation. However, the biochemical conversion of paddy straw into biogas is limited by its complex lignocellulosic structure, which makes it resistant to microbial degradation. Therefore, pretreatment of biomass is a critical step to enhance its digestibility and improve the overall efficiency of biogas production. Objective The primary objective of pretreatment is to break down the structural and compositional barriers within lignocellulosic biomass that hinder microbial degradation and enzymatic hydrolysis. Specifically, pretreatment aims to: 1. Disrupt lignin structure and reduce cellulose crystallinity. 2. Increase surface area and porosity of the biomass for microbial access. 3. Improve enzymatic hydrolysis efficiency for higher sugar and methane yields. 4. Minimize sugar loss and avoid the formation of inhibitory byproducts. 5. Enhance biogas yield and the rate of biodegradation. 6. Achieve these improvements in a cost-effective and scalable manner

Objective To produce ethanol from lignocellulosic biomass (e.g., paddy straw) through a series of biochemical processes pretreatment, enzymatic saccharification, and microbial fermentation and to evaluate sugar yield, ethanol concentration, and fermentation efficiency. Introduction and Theoretical Background Ethanol (C2H5OH), commonly known as ethyl alcohol, is one of the most important biofuels and renewable energy sources in the modern era. It is a clear, volatile, and flammable liquid that can be used both as a fuel additive (blended with gasoline to form gasohol) and as an independent energy source in modified internal combustion engines. In addition, ethanol is extensively used in the pharmaceutical, beverage, and chemical industries. Globally, more than 30 billion litres of ethanol are produced annually, primarily via fermentation of sugar-rich feedstocks such as sugarcane juice, molasses, and starch-based crops like maize and wheat. However, reliance on these food-based resources has raised sustainability and food security concerns. Therefore, attention has increasingly shifted toward lignocellulosic biomass, such as agricultural residues (paddy straw, corn stover, bagasse, etc.), which are abundant, renewable, and inexpensive. Paddy straw, a by-product of rice cultivation, is a promising raw material for bioethanol production due to its high cellulose (30–40%) and hemicellulose (20–30%) content. However, the complex structure of lignocellulosic biomass, reinforced by lignin and silica, restricts enzyme accessibility to polysaccharides. Hence, pretreatment is essential to break down lignin and enhance enzyme digestibility before fermentation.

Solar energy is the energy emitted by the sun in the form of electromagnetic radiation. It is the most abundant, renewable, and sustainable energy resource available on Earth. Every hour, the Earth receives more energy from the sun than the entire human population consumes in a year. This makes solar energy a key candidate for solving the world’s growing energy needs while addressing environmental concerns. The solar energy reaching Earth can be harnessed and converted into useful forms of energy Solar Photovoltaic Fencing Solar photovoltaic fencing utilizes solar energy to provide an effective security solution, using high-voltage electric pulses to deter intruders or animals. The system operates by converting solar energy into electricity, which is then stored in a battery for later use. The battery powers an energizer that sends high-voltage pulses along the fence, creating an electric shock when an intruder touches the live wire. System Components and Working 1. Solar Module: Converts sunlight into direct current (DC) electricity, which charges the battery. 2. Battery: Stores the energy generated by the solar panel. The 12V/100AH battery allows the system to operate even at night or during cloudy days. 3. Energizer: The energizer is the heart of the system, generating high-voltage pulses. It works by sending electrical pulses at regular intervals (usually one pulse per second) through the fence. The energizer is powered by the battery.