Biogas Magazine Edition 17

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Biogas Magazine | Edition 17 | 1

SEPURAN® GREEN for efficient Biogas purifications More than 600 plants running successfully

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Features • Green technology - no chemical use and no waste water • No emissions into the environment • Best price performance • High methane yield up to >99 % • High purities >99% (patented 3-stage process) • Highest energy efficiency • Easy to operate - start & stop • Low maintenance • Flexible and easily expanded To know more, contact: Evonik India Pvt. Ltd. Mr. Aashish Maheshwari, Associate Business Director, High Performance Polymers +91 22 6723 8861 | +91 98205 17384 | aashish.maheshwari@evonik.com

Index IBA News IBA’s commitment towards leapfrogging the prospects in the biogas/bio-CNG industry (Period: Jul, 21-Sept, 21)

08

National Corner Removing Barriers to Sustainable Waste Management in India

12

Compressed Biogas (CBG) potential from agricultural residues - An Indian prespective

34

International Corner Analyzing Biogas Components Quickly with Micro Gas Chromatography

17

Foundation of Gazpack

23

Energy from livestock waste

25

Pros and Cons of different types of Anaerobic Digester

28

Published by

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In-Cooperation with

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Foreword Dear Reader, Hope you’re doing well and staying safe! We are now in the in post COVID 19 era, wherein concentrated efforts by the countrymen has led to reduction in number of cases resulting in a sigh of relief throughout the country. India is demonstrating its mettle, and continuously ramping up efforts to vaccinate its vast population.

IBA is putting all the efforts to ensure that biogas’ growth trajectory is accelerated. In September 2021, IBA organized a physical Bio-Energy pavilion at the Renewable Energy India Expo from September 15 to 17, 2021 at Indian Expo Mart, Greater Noida, India. The event was the first of its kind following the second wave of the COVID, and it witnessed overwhelming participation from the trade show visitors. On the final day of the event, two conference sessions, focused on bioenergy (including bio-hydrogen issues) were held, which drew houseful participation.

In this edition, we have brought some extremely fascinating articles for you. They address the contemporary burning issues along with innovative technologies. Insights into the Indian agricultural sector give a broader picture about its related biogas potential.

Burning of agricultural residues, esp. during the winter, has always been a topic of discussion in Northern India. We need to ensure that the correct solution is implemented; otherwise it will contribute to ever compounding issues on green- house gas emission along with health hazards. The recently published IPCC report of 2021 is already ringing the alarming bells as most of the inflicted damage is irreversible.

via biogas. The article showcases the different methods to treat organic waste and the advantages through the biogas route. The article on micro gas chromatography will bring to your notice a technology that can be used to analyse the composition of biogas. For the plant owners, operators, and investors, biogas/ substrate/slurry testing always plays an important role. Such analysis informs about the health of the running plant, and gives a realistic idea about the yield from a given substrate, targeted by an investor.

An article on biogas up- gradation technology discuss innovative technology that can manage low throughputs, and produces waste- free upgraded biogas.

Essence of stirring technique, using a case study based on livestock waste, is discussed in one of the article. In another write-up, different digester technologies are discussed, thus providing insights to make unbiased comparisons amongst them.

As always, our primary objective through our magazine is to keep you abreast with the new developments of the sector.

We’d like also to hear your thoughts as well. To share your thoughts and articles, please write to us at info@biogas-india. com We wish you a safe, healthy, and greener future!

Another article in this issue discusses the massive problem of waste management

Mr. A. R. Shukla

President Indian Biogas Association

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IBA’s commitment towards leapfrogging the prospects in the biogas/bio-CNG industry Period: Jul’ 21 - 21 Sept’ 21 st

IBA organize the Bio-Energy Pavilion 2021 at REI- Expo, Greater Noida:

T

he second edition of the Bio-Energy Pavilion, an initiative of Indian Biogas Association (IBA), was held from September 15, 2021 to September 17, 2021 at the Renewable Energy India Expo, India Expo Mart, Greater Noida. Despite the uncertainty prevailing during built-up to the event, the everimproving COVID situation in India paved way for the event organizers to successfully pull off the event, upon implementing adequate safety protocols issued by the Government of India.

The event turned out to be the first physical trade show after the pandemic lockdown that began in 2021, and it witnessed an overwhelming response with a significant footfall of trade visitors.

Few stats from the show are as cited below: •

Number of Brands: 171

•

Number of Trade Visitors: 12,987

•

Number of Speakers: 135

•

Number of Delegates & VIPs: 540

The Bio-Energy Pavilion, a self-owned booth set-up by IBA, was exhibited at REI-Expo. A conference on biogas and related topics was as well organized by IBA on the final day, i.e., September 17, 2021. The booth featured seven sponsors, spanning a wide spectrum of biogas industry, thus disseminating the comprehensive information about biogas industry, and promoting biogas as the sustainable fuel of choice for India. The Pavilion attracted over 1000 trade visitors at the pavilion and witnessed over 100 business meetings. The pavilion catered diverse group of industry stakeholders, especially from the biogas domain; like SATAT LOI holders, embassy representatives, investors, aspiring entrepreneurs, environmental enthusiasts, academics associates, and NGOs associated with renewables.

The two sessions covered in the Biogas Conference focused on the “SATAT scheme

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& Evolution of Biogas Ecosystem” and “Bioenergy”, respectively. The Biogas Conference included panel discussions and presentations by national and international experts from across the biogas industry. In the biogas conference, participation of over 90 participants and over 10 eminent speakers were witnessed.

The conference proved to be an ideal platform for Biogas and Bio-energy to congregate, discuss industry challenges, deep-diving into possible solutions, which would indeed help in proliferation of industries in a renewable domain or even otherwise looking for sustainable solutions.

Being the only booth in the field of bio-energy, and biogas in particular, it attracted many diverse categories of enthusiasts looking to foray into the field. For them, it laid tremendous networking opportunities with relevant stakeholders and subject experts.

GEF-MNRE-UNIDO Launch the loan interest subvention scheme: On 10th August 2021, MNRE in association with UNIDO and GEF launched the loan interest subvention scheme for demonstration of innovative industrial organic waste to energy bio-methanation projects and business models.

A GIS-based inventory tool of organic waste streams was also unveiled. On the occasion, a panel was organized by IBA in support of UNIDO and MNRE. The topic being, ‘Waste to energy through bio methanation; making technology and business model work’. Mr. Gaurav Kedia, Chairman, IBA was the moderator for the session.

IBA organized and participated in series of webinars: On August 06, 2021, IBA along with REI India organized a seminar on “The Potential of Biogas between Dream and Reality”. The event was focused on the overall development and sustainability of the biogas in India along with an opportunity to understand and enter the fastgrowing Bioenergy market in India. Speakers

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Glimpses of Bio-Energy Pavilion 2021 from IBA, Armatec-FTS, Biogas Academy and ETA Gas presented in the session.

Furthermore, in August, IBA represented the training seminar organized by SAARC Energy Centre and IIT Roorkee, and also a webinar on Compressed Biogas organized by Diligentia, which saw participation from OMCs and LOI holders.

Continuing with its series of webinars, IBA along with World Biogas Association (WBA) is organizing a virtual conference, “Biogas: Opportunities India” on October 07, 2021. The objective is to give a glimpse of the Biogas industry of India to foreign investors. For more information, kindly visit: https://biogas-india. com/biogas-opportunities-india/

synchronization amongst working areas of the different Central Ministry departments (featuring in biogas ecosystem). The collected response of the survey has been submitted to NITI Aayog for their onwards suggestion Additionally, IBA organized a series of Meetings with various State Nodal Agencies (SNAs), namely Karnataka, Uttar Pradesh, Haryana, Punjab, Maharashtra, Goa), and Gujarat. The interactions were scheduled to understand the present facilitation provided by the state govt. and the cooperation/ support that can be provided by IBA for further streamlining of the sector in respective states.

Survey floated by IBA at the behest of NITI Aayog: On request from NITI Aayog, in July, a survey was floated amongst IBA members to gauge the need for streamlining and the degree of

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Bio-Energy Pavilion 2021

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Biogas Conference 2019

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Removing Barriers to Sustainable Waste Management in India Adapted from a joint publication by Clarke Energy and the UK India Business Council

I

ndia is the 5th largest economy in the world today with an ambition to become a US$3 trillion economy by 2025, climbing to a position of the 3rd largest economy in the world.

Accompanied by this ambitious target is the fact that by 2022 India will be the most populous nation with its urban population increasing at a rate of 3-3.5% per annum.

Nonetheless, this surge brings about an increase in urbanization, industrialization, and demand across utilities such as food, water, energy, housing, and sanitation. These multifaceted requirements are crucial for economic growth, but what must be ensured is that the economic growth is backed by sustainable and judicious utilization of natural resources.

As we see today, with the rapid increase in India’s industrial landscape and population, and Government of India’s vision for “Power for All”, the energy demands have grown manifold and

the energy consumption for India is expected to surge from the present 6 percent to 11 percent by 2040, while power generation is expected to increase by 207% to 4781 TWh by 2040. To ensure fulfilment of these demands, inevitable pressure will be put on natural resources. Though there is growth in the usage of renewable sources to cater to the growing energy demands, there still will be dependence on coal to a very large extent to be the primary energy source, almost accounting for 80% of the total output by 2040.

It is no doubt that usage of coal to this large extent will only add to India’s growing environmental concerns and augmenting CO2 emissions. Being a signatory to the Paris Agreement and adopting the United Nations 17 Sustainable Development Goals (SDGs), India, today must adopt alternative means of energy generation – and one of the key resources here would be “Waste” – the municipal solid waste (MSW) that India generates.

Municipal solid waste

Anaerobic digestion

Fermentation

Wet organics

Dry organics

Biochemical conversion

Thermal conversion

Compost

Pyrolysis / gasification

Biowaste Treatment Technology Options Anaerobic digestion is a biochemical process that utilizes anaerobic bacteria to degrade the organic fraction of waste in the absence of oxygen. This method is very useful for wastes containing a high percentage of moisture (>50%). After digestion, two end-products are released, namely biogas (mainly consisting of methane 55–60% and carbon dioxide 30–45% www.biogas-india.com

Gasification

Refuse derived fuel pelletization

having energy content of about 20-25 MJ/m3) and a bio-slurry that can be utilized as organic fertilizer. Biomethanation is a solution for processing biodegradable waste, which remains underexploited.

In addition to the anaerobic digestion process being a net energy-producing process, wherein the renewable fuel can be used for electricity generation, heating purposes and/or biomethane, Biogas Magazine | Edition 17 | 12

biogas industry. Greater public support for the adoption of biogas systems could result in more opportunity for biogas development. In addition to lack of awareness of biogas benefits, we share a few of the other challenges: Policy & Regulatory Issues

Fig 1: Biogas & Anaerobic Digestion (Source: World Biogas Association)

it also helps eliminates odour-producing, nutrient-rich organic fertilizer, helps maximize recycling, and reduces greenhouse gas emissions. The World Biogas Association recently published a report “The Global Potential of Biogas”, which highlights the potential of anaerobic digestion technology to reduce global carbon dioxide emissions by 10-13%.

In most Indian cities, MSW collection, segregation, transportation, processing and disposal are carried out by the respective municipal corporations, while state governments enforce regulatory policies. In some cities like Mumbai, Chennai, Delhi, Bengaluru, Hyderabad and Ahmedabad, garbage disposal is done

by Public-Private Partnerships (PPPs). The private sector has been involved in door-todoor collection of solid waste, street sweeping (in a limited way), secondary storage and transportation, and for treatment and disposal of waste. However, the regulatory framework for the sector has not been updated and equipped with the necessary execution plans or clauses, which mandate effective implementation.

Financial Issues

In comparison to composting, biomethanation requires less land and reduces disposed waste volume to landfills.

1. Heavy reliance on government subsidies.

Also, Central Finance Assistance for MSW (in segregated form) biogas power plants is Rs. 3.0 crores/MW ($397K per MW) whereas that using incineration or any other thermal technology is Rs. 5.0 crores/MW ($662K per MW).

Challenges with Biomethanation in Treating MSW

2. Lukewarm response of banks and financial institutions including weak supply chain.

The process of biomethanation appears to be a more reliable and promising technology as it not only aims to solve the problem of organic solid waste, but also provides sustainable energy in the form of biogas. Moreover, it is eco-friendly and less labour intensive.

In India, the process of biomethanation is still unpopular due to lack of due consideration by the government. Of late, composition of the urban solid waste used as a feedstock is the most important determining factor in the process of biomethanation. The most significant types of solid wastes with considerable biomethanation potential are MSW, kitchen waste, garden waste, leave-aside energy crops (maize, grass, sugarcane, etc.), as it brings in discussions of food security over energy security.

Investors, policy makers, and the public could benefit from gaining a deeper understanding of the value of investing in biogas systems and a

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3. Low level of private sector participation due to lack of market and debt finance for the projects.

4. Difficulties in obtaining long-term Power Purchase Agreement (PPAs) and reasonable tariff from state Discoms.

5. Government’s heavy focus on solar and wind has impacted development of the WtE sector, even though these projects aim to reduce the colossal amount of solid waste accumulating in cities and towns all over India.

Project & Structural Challenges 1. Lack of technical and financial feasibility of the projects – primarily due to improper revenue estimations, waste generator charge collection and estimating contingencies, for e.g. resistance from

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locals (all WtE technologies are not clean and green), antisocial elements creating hurdles in waste collection and transportation, and availability of realistic risk assessment models.

50-60% of the overall revenue stack and this money needs to come from municipalities, all of which are not financially self-sufficient.

Technology Challenges

The scale of the problem is unclear, as there is no authentic and reliable data available for waste generation quantities and disposal. In unison, India lacks adequate environmental, technical, and economic performance data related to biogas-system production of energy, co-products, greenhouse gas and other emissions, and water quality benefits, required market analysis standpoint.

1. Appropriate technology solutions, which are environment-friendly and can treat the quality of mixed waste generated in India, are not economical. The treatment technologies that are available require mechanical separation using trommels, screens air density separators or else manual separation in smaller plants. This adds to project costs.

2. Poor town planning and spatial framework to facilitate appropriate distributed waste treatment and energy generation facilities in urban areas.

2. The technology options for WtE are not yet established thus leading to uncertainty with the implementing agencies about the suitability of technologies and preparedness of ULBs for managing these projects.

3. Scarcity of land.

4. Quality of waste - The fundamental reason for the inefficiency of WtE plants is the quality and composition of waste. MSW in India has low calorific value and high moisture content. As most wastes sent to the WtE plants are unsegregated, they also have high inert content. These wastes are just not suitable for burning in the incineration technology driven plants. To burn them additional fuel is required which makes these plants expensive to run.

3. There has been a failure in the incineration plants due to their inability to handle mixed waste. The WtE plants have also triggered widespread criticism among citizens on account of the environmental impact it has.

5. Non-integration of informal sector – One of the largest and most significant stakeholders in waste treatment is the informal or the unorganized sector involving waste pickers/ informal rag pickers. They are also the first point of contact responsible for collection and segregation of waste as well. Low levels of awareness within this segment affect the quality of waste generated. Unfortunately, this sector is not managed or controlled by the ULBs or State or Central government, hence it becomes challenging to monitor and manage their activities.

Failure of WtE projects is mainly attributed to non-economic feasibility, lack of sustainable planning, high-cost technologies, non-availability of the required segregated waste, and lack of coordination between the stakeholders.

6. Although many people are involved in this sector, solid waste management (SWM) has a lower priority than sanitation, health, and other issues.

7. In India, WtE projects are extremely complicated and expensive to build. In addition to other economic streams, such projects usually require high tipping fees. A tipping fee is what the trash hauler must pay to dump the trash at the facility. With WtE projects, the tipping fee can end up being www.biogas-india.com

4. The PPP options that can sustain such technology solutions are insufficient due to lack of funds.

Recommendations

Government Central government should evaluate the potential of a tax on the dumping of waste to make sustainable waste treatment technologies more commercially viable.

All the states should have a SWM authority with experts on various aspects of MSW, including selection of appropriate WtE technology suitable for the different types of waste composition, contracting, financial management, along with the overall long-term carbon emission reduction potential of a given scheme. This authority may be made responsible for the following: •

Document the status of SWM and create a mechanism for continuous update of the status.

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•

Assess the correct situation of MSW in the municipal areas within a state and identify the gaps that need to be bridged.

•

Prepare norms for assessing the requirement of tools, equipment, vehicle, manpower for collection and transportation of waste, and for setting up processing and disposal facilities as per guidelines outlined.

All municipal corporations should have MSW Management Departments alongside minimum technical and supervisory staff to ensure efficient MSW service delivery and strengthen ULBs to enter contracts. At their level: •

Efforts should be made to educate the waste generators to minimize the waste and segregate the waste at source.

•

Informal and unorganized sector should be assimilated in this process and awareness amongst them should be created on proper waste collection and segregation methodology. They play an important role in SWM within the country.

•

•

Separate arrangements for collection, transportation of domestic, trade, institutional and market waste should be made to ensure that such waste is directly delivered at the waste processing facility meant for biodegradable and recyclable waste.

Improvements to be made to town planning.

Suitable sites should be earmarked at local level for the development of sustainable waste treatment infrastructure.

With proper MSW management facilities, the Government of India, other ministries and nodal agencies involved in this sector have the opportunity to improve the living condition of urban people, improve public health, conserve resources, mitigate GHG emissions and generate energy by adopting appropriate technology.

Also, rapid depletion of non-renewable energy resources and the threat of global climate change have forced the energy sector in India to look for alternative sources of energy to generate enough energy and preserve the environment at the same time. Unfortunately, the technology for utilization of green energy remains very expensive or unable to satisfy India’s need for energy, or both. There is, however, one alternative source of energy which has great potential when it comes to efficient power generation at acceptable cost – biogas.

Utilization of biogas for electricity and/ or biomethane will bring in various other stakeholders into consideration and other challenges, an aspect not covered under this article.

For detailed data and references, please refer to the White Paper titled “Removing Barriers to Sustainable Municipal Solid Waste Management Using Anaerobic Digestion” available on link: https://www.clarke-energy.com/wp-content/ uploads/2020/09/Whitepaper-on-RemovingBarriers-to-Sustainable-Municipal-Solid-WasteManagment-Using-Anaerobic-Digestion.pdf

Authors:

Technology •

•

Different technologies for treating different kinds of waste are available in the market.

Applying all the possible technologies in an integrated way can help to reach the goals of sustainability. Therefore, open dumping and unsanitary landfilling are not sustainable options and cannot be recommended for treating waste.

Increase in quantum and complexity of waste with increase in population, economy of the country and fluctuations in crude prices have demanded serious consideration of biomethanation technology implementation, wherein high calorific value biogas generated can be used for electricity and/or as transportation fuel.

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Abhijit Rajguru Clarke Energy

Alex Marshall Clarke Energy

Surbhi Mathur UK India Business Council Web: www.clarke-energy.com

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Fast compositional analysis for biogas applications.

Micro GC Fusion® Small, transportable, and modular gas chromatograph capable of analyzing typical biogas components within minutes n

Analysis in minutes

n

24/7 analysis

n

Easy to use, web-based interface

n

Temperature programming for expanded analysis and column cleaning

INFICON PTE LTD 3A, International Business Park Tower B, #06-13, ICON@IBP, Singapore 609935 phone: +65.6631.0300

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reach.singapore@inficon.com Biogas email: Magazine | Edition 17 | 16 www.inficon.com

Analyzing Biogas Components Quickly with Micro Gas Chromatography Introduction

C

limate change is accelerating the need for renewable energy sources such as biogas.

Biogas is composed of gases produced by the anaerobic digestion of organic compounds.

This can happen as a natural byproduct of decomposition, as seen in landfills, or with the use of controlled anaerobic digesters used to break down biomass sources, such as animal or industrial waste. The biogas from those materials can be used for electricity, thermal, transportation, and pipeline gas due to the high energy content of methane, typically 50-75%. The methane content can vary depending on the source of the gas.

Monitoring the composition of biogas is a critical part of keeping the process stable and efficient.

In addition, to utilize biogas for pipeline gas, the carbon dioxide (CO2) content must be reduced to increase the overall percentage of methane and the calorific value. Analytical instruments, such as micro gas chromatographs (GC), monitor and track important changes in gas composition.

They provide a fast and reliable gas composition analysis for common biogas components from ppm up to high percent levels.

option compares the thermal conductivity of the compound versus a pure carrier gas such as helium or argon, and records the difference. The results are displayed as a chromatogram and a report which contains the concentration of each individual component.

Using chromatography, the composition of each compound can be tracked and monitored over time. Runs are typically only minutes in length and can be run consecutively to ensure the stability and efficiency of biogas plant processes. Chromatography can also be used to analyze inhibitors to the process such as hydrogen sulfide (H2S).

Micro GC Technology Provides Fast Results and a Small, Transportable Option Micro GC technology differs from traditional chromatography because it offers a fast analysis in a transportable chassis. Micro GCs can be taken into the field for on-site gas analyses, such as those conducted on landfills, and has the benefit of maintaining sample integrity and providing results quickly. Alternately, the Micro GC can be set up in a fixed location and the small footprint is optimal when there is not much space available.

Micro GCs are modular – each module containing an injector, column, and detector. The ability to run up to four modules simultaneously ensures that results are within a few minutes.

For biogas components, a 2-module Micro GC is recommended.

How a Gas Chromatography is Beneficial in Analyzing Biogas Components Gas chromatography is a well-known analytical technique used to separate and quantify gases.

A mixed sample, such as biogas, is introduced via a sample inlet and injected onto chemical coated columns in order to separate hydrogen, oxygen, nitrogen, carbon monoxide (CO), CO2, and methane. Once separated, these compounds are quantified using a detector, such as a thermal conductivity detector (TCD). This detector www.biogas-india.com

Micro GC has the ability to temperature ramp the columns. This ensures that heavy components fully elute from the column, keeping them clean.

The temperature ramping also improves peak shape and run time.

Below are example chromatograms for biogas components using a 2-module instrument.

Module A was configured with a 10 m Molsieve column for hydrogen, oxygen, nitrogen, methane and CO. Module B was configured with a Q-Bond column for CO2, and this column can also be used to potentially analyze H2S or heavier hydrocarbons.

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Figure 1: Chromatogram of Module A - Molsieve (Argon Carrier)

Figure 2: Chromatogram of Module B – Q-Bond (Argon Carrier)

The Molsieve column on module A was configured with a backflush injector due to the high amount of carbon dioxide (CO2) present in biogas. The backflush injector utilizes a short pre-column to trap heavier compounds, such as water and CO2, and prevent them from entering the analytical column. These undesired compounds are then backflushed to vent. This minimizes the potential carryover effect of CO2.

Micro GCs can be run using different carrier

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gases, typically argon and helium. Argon is the preferred carrier gas for Module A when hydrogen is present in the sample. The thermal conductivities of hydrogen and helium are very similar to each other, meaning the peak sensitivity of hydrogen using helium as a carrier gas would be reduced. Therefore, argon is the recommended carrier gas for samples containing hydrogen. If no hydrogen is present in the sample, helium can be used to provide better sensitivity for the nitrogen, oxygen, methane, and CO peaks.

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During one experiment, all components in the calibration standard were analyzed within 3 minutes. Ten consecutive runs of each carrier gas were used to calculate the relative standard deviation.

All compounds in both argon and helium carrier gas showed excellent repeatability and had a peak area %RSD of <1.5% and a retention time %RSD of <0.1% Gas Chromatography is an Excellent Choice for Biogas Composition Analysis Compositional analysis of methane, carbon dioxide, and other fixed gases in biogas is an important factor in ensuring the process in biogas plants is stable and efficient. Gas chromatography is a well-known analytical technique that provides a way to separate and quantify these components. In addition, Micro GC technology provides additional benefits, such as being a fast, transportable option while still providing excellent repeatability.

Mr. Chris Rohrer

Ms. Debbie Alcorn

Esteemed co-author Summer Intern to INFICON INC.

Esteemed co-author INFICON Product Manager, Energy Segment

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Mr. Gary Heng Esteemed co-author Assistant Sales Manager, Energy and Security Segment

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According to customer requirements

>99.5% Methane Recovery

Regenerable adsorbent Sulafer®

Gazpack is a Dutch-based company that manufactures and supplies biogas upgrading installations made specifically to customer requirements. We specialize in the desulphurization of raw and contaminated biogas, we are committed to reducing environmental pollution.

Our Suluway® was initially built to convert large capacities of biogas to biomethane (>1500 Nm3/h), while on today’s market, for example, India, there is a high demand for small upgrading capacities. Therefore, Gazpack invented Sulago®, thus we can deliver smallscale upgrading solutions according to customer specifications. However, Sulago® has an appealing CAPEX-OPEX ratio, especially when it comes to capacities between 250 Nm³/h- 600 Nm³/h.

In contrast to other systems, which are using activated carbon, Sulago® is using our own developed Sulafer®.

Sulafer® has the capability to regenerate without losing the ability to absorb H₂S. Therefore, it has twice the lifespan in contrast to carbon.

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For any inquiries, please call or email us on: (+31) 0111-820100 gazpack@gazpack.nl

Biogas Magazine | Edition 17 | 20

Foundation of Gazpack

G

azpack was founded in 2006 as a research division at Airpack Nederland BV. Due to Airpack’s involvement in the international oil and gas business, founder Mr. JP Warnar wondered how gas flaring could be controlled or turned into valuable products. Oil wells contain both oil and gas, which are extracted during the drilling process. This oil gas is extremely contaminated therefore it is frequently flared instead of being used. Some technologies for cleaning this oil gas were/are already in the market, but they had significant drawbacks, such as producing a substantial amount of trash. As a result, researchers began looking for a new and better approach to purify oil gas.

After 8 years of extensive research together with several universities, a new desulphurization method was developed that converts the contaminated oil gas into several useful products. Biogas turned out to be very similar in composition to oil gas, making it the perfect alternative to test the pilot installation of Gazpack. After successful testing, the patented system has now been fully developed to be implemented in the biogas industry. This industry will benefit from a highly innovative and high-quality product that produces clean gas, usable sulfur gas, and sulfuric acid without any waste.

Striving for flexibility and sustainability at the same time Our main objective is to decrese greenhouse emissions. Several countries are willing to meet the requirements of the Paris Climate Change Agreement in 2030., and to achieve this goal, not only countries such as China, Brazil, and India, but also within the European Union are investing in environmentally friendly energy

sources, like biogas. The Asia Pacific market is growing at the highest pace w.r.t building biogas plants. We are willing to support by offering the widest possible range of products to biogas producers around the world.

As a daughter company of Airpack Netherlands, Gazpack is specialized in desulphurization services, tailored to the needs of its customers.

We can adapt our design, and make our units suitable for every requirement. Therefore, we can deliver small capacities (I.e., 250 Nm³/h), or large capacities (I.e., 2500 Nm³/h) We manufacture two patented gas upgrading systems for the supply of renewable natural gas (RNG) from biogas: Sulaway® and Sulago®.

Sulaway® is for biogas quantities more than 1500 Nm³/h, and is waste-free. The H2S adsorbent (Sulabead®) is regenerated, and transformed into acid water with no waste and odor. Sulago® is for small capacities, in which adsorbent must be replaced regularly, but does not contain active carbon. On the contrary, the saturated adsorbent (Sulafer®) will be exchanged for new at lower costs than activated carbon.

A small-scale upgrading solution: Sulago® As previously stated, Suluway® was designed to convert huge volumes of biogas to biomethane (>1500 Nm3/h), but there is a considerable need for small upgrading capacity in today’s market, such as India. , Thus Sulago® was designed, through which we can deliver small-scale upgrading solutions according to customer specifications. However, Sulago® has an appealing CAPEX; OPEX ratio especially when it comes to capacities between 250 Nm³/h- 600 Nm³/h.

CAPEX; OPEX table (Gazpack blue) Sulago®: 5 years (placed under the table)

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CAPEX; OPEX table (Gazpack blue) Sulago®: 10 years (placed under the table)

How it works •

Sour gas passes a dryer-cooler with a filter separator to avoid moist gas entering the Sulago® towers.

•

The gas enters the first Sulago® tower to absorb the largest portion of H2S. The second tower takes care of an absorption level of 3 ppmV H2S.

•

The role of the compressor is to boost the pressure up to 8 bar and leads it through two membranes.

•

The first membrane removes the largest CO2 percentage and permeate it with the surplus of air into the atmosphere. The second membrane brings CO2 load at spec - 3% into the gas stock.

For safety measures, an enclosure is built with a ventilation system to avoid odor leakage. The outlet of the permeate of the membranes, and enclosure fan is hooked up into an odor absorbent filter to blow off CO2 into the atmosphere.

However, capturing CO2₂is also feasible within our system, to make the system as circular as

possible, the carbon gas can be liquefied, and stored, which means an extra stream of revenue is feasible within our system. Due to liquefaction of high-quality CO2, possibilities grow to use it for greenhouses or other purposes.

Recyclable adsorbent: Sulafer® In contrast to other systems, which are using activated carbon, Sulago® is using self-developed Sulafer®. Sulafer® can be regenerated without losing the ability to absorb H₂S. However to besides that the cleaning of the adsorbent is feasible within our factory. Thus, it still has twice the lifespan in contrast to typical activated carbon.

Sulafer® has important advantages such as: •

Waste disposal of Sulafer® does not contain any form of carbon.

•

⦁Low-cost price.

•

⦁It has a better absorb capacity and it can handle high H2S content (>1000 ppmV), which can be regenerated and used again.

Please see below table for the costs of Sulafer®:

To elaborate on the low costs of Sulafer®, following example are based on a functioning power plant that cleans 500 Nm³/h biogas at 200 ppmV H2S.

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Biogas Magazine | Edition 17 | 22

Low maintenance attention For an uninterrupted gas supply, high-quality materials are selected such as stainless-steel coolers, vessels, membrane housing, and longlife compressors (less replacements of oil).

The guaranteed lifetime of Sulafer® is 4000 operating hours which is based on a H2S content of 200 ppmV and capacity of 180 Nm³/h.

If you have additional questions regarding these applications, please reach out to our sales department by sending an e-mail to gazpack@gazpack.nl or by sending an e-mail to gazpack@gazpack.nl, call us at +31 (0)111820100 or visit our website: https://www. gazpack.nl/

Conclusion Sulago® is quite competitive for small biogas capacities (<600 Nm³/h) and has a very interesting Capex-Opex ratio, which could be interesting for small biogas plants. Besides that Sulafer® can regenerate, which keeps the maintenance costs low. Sulafer® does not contain any form of carbon, which makes carbon footprint zero.

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Mr. Jan Piet Warnar President Gazpack BV.

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SUMA, pumping and mixing technology from one hand.

Looking for longterm digester efficiency?

60 years of experience in mixing of various substrates Tailored solutions Long-term reliability High operational safety User friendly application

WE SOLVE & MOVE. SUMA Rührtechnik GmbH Martinszeller Str. 21 | 87477 Sulzberg/Germany www.biogas-india.com Biogas Magazine | Edition 17 | 24 E-Mail: info@suma.de | www.suma.de/en

Energy from livestock waste

W

hile in other European countries lately status quo prevails for agricultural biogas plants, in Italy the density of biogas plants continues to grow: currently, in Itlay there are about 1,500 anaerobic digesters and the potential has not yet been exhausted yet.

plants usually reduce liquid manure overflow to a minimum.

Although, biogas is not as well-accepted in Italy as energy from other renewable sources, it is Europe’s second-largest producer of biogas energy after Germany.While China is the international leader, Italy remains in third place. Italy replenished biogas plant subsidies in 2018 with the support of the European Union.

The production and direct feed-in of biomethane should be promoted more intensely.

About the plant

Smaller, but dense At times, small to medium-sized plants dominate the biogas landscape in Italy. However, they are also significant in the decentralisation of energy generation. In most cases, the biogas plants are part of agricultural operations. Additionally, the

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One of these distinctive biogas plants is operated in Cremona since 2017. The motivation was to use the waste from livestock farming.

The operator produces 249 kW on an area of 1,400 m². The plant consists of partially subterranean pre-pit with a diameter of 8 m and a height of 4 m in which the substrate is blended.

The fermenter is also partly underground, with a diameter of 24 metres, and a height of 8 metres.

The substrate consists of 70% cattle manure, agricultural by-products, and by-products from the production of oilseeds. The electricity generated is fed into the grid on a constant load basis, with only slight fluctuations throughout the year. The operator uses the waste heat for the fermenter inhouse. An expansion of the waste heat supply to adjacent households is also planned.

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Stirring technology The stirring technology comes from the German specialist SUMA Rührtechnik GmbH in Sulzberg (a member of the Indian Biogas Association).

The Optimix 2G submersible agitator is installed in the pre-pit. Three shaft agitators are stirring in the fermenter: one Giantmix FR, and two Giantmix FT, each with 15 kW output. The shaft agitators of SUMA can be operated up to 8 meters below filling level, containing substrate with dry matter content up to 14 %. Due to the horizontal and vertical adjustability of +/- 30° each, it is possible to react flexibly to different substrate states and conditions. Even fluctuating filling levels, floating or sinking layers can be stirred in a targeted manner. Low-noise spur gears meet the photometric requirements even in densely populated regions.

Conclusion When it comes to the needs for agitator

technology from the operator’s perspective, simplicity, ease of maintenance, and adaptability were at the top of the list. After two years of operation, stirring performance were highly satisfactory, especially w.r.t maintenance required and ease of maintenance! The energy efficiency of the agitators is highly impressive as well. The majority of motor and gearbox maintenance can also be done without having to lower the filling level in the vessel, opening the vessel or, climbing and getting into the vessel.

Although an Italian stirring technology manufacturer is hardly half an hour away from the location, SUMA stirring technology will be used in another plant that’s being planned at the moment. “The cooperation with SUMA has proven to be very constructive and productive.

This is why we will continue to stir with SUMA in the future”.

-------

Giantmix FR and Giantmix FT; hydraulic height adjustment via hand pump.

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Biogas Magazine | Edition 17 | 26

About SUMA Stirring Technology: For over 60 years, SUMA Rührtechnik GmbH has specialised in the manufacture of agitators. In the biogas, agricultural and industrial sectors.

The agitator manufacturer from Sulzberg, in the Allgäu region of Germany, is assuming a pioneering role worldwide. The company develops, manufactures and optimises its products for the benefit of its customers, and solves complex challenges with innovation and know-how. Its decades of experience form the basis for continuous further development and new innovations. SUMA looks back on its strong track record and can look forward to a great future.

WE SOLVE & MOVE. More information online: https://www.suma.de/ EN/

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Mr. Arne Kleinknecht SUMA Stirring Technology

Biogas Magazine | Edition 17 | 27

Pros and Cons of different Types of Anaerobic Digester

A

s I, Paul L Harris have been mainly involved in Agricultural and Domestic digesters, with a few years of minimal activity recently, my main comments relate to a certain scale of digestion unit, but the thoughts will also probably help those interested in other types and scales of digesters.

Poly Plug Flow Digester A lot of my work has been centered on the “Poly Plug Flow” type of digester, so I will start from the same. These digesters can be made of cheap plastic film, more durable plastics like Geoliner or Red Mud PVC, rigid plastics, fiber glass, concrete, or steel. Plug flow digesters typically have their length 5-10 times the diameter, so are long and skinny compared to most designs. This means that there is minimal mixing through the digester, so a batch of input basically moves through the digester as a “plug”, just as when we eat a meal it is moved through our own digestive system in a linear fashion by “Peristalsis” (hence the name). As a result, all material will undergo almost the same

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Retention Time and any detrimental additions to the feed are kept localized.

A Poly Plug Flow digester is an example of flexible bag storage, where gas is put into a flexible bag (maybe in the digester itself or in a separate bag containing only biogas).

Pressure can be developed by placing weight on the storage bag, where Pressure = Force / Area, so Pressure (kPa) = Weight (kg) / Area of Contact (m2) X 9.8 /1000 and Area of Contact = Length(m) X Width(m) for a rectangle or π X Diameter 2/4 with Diameter in meters.

Indian Floating Drum Digester A second common type of digester is the “Indian Floating Drum digester”, usually constructed from concrete, steel and rigid plastic/fiber glass, in various combinations. In the Indian Floating Drum gas causes a rigid container to float in a water/digestate bath (hence the name). Again, pressure is developed by the weight of the “Drum” (plus extra weights if necessary) and the digester and gas holder may be a single unit, giving a compact footprint, or the gas holder

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may be a separate unit using water a seal (which reduces methane emissions and smells and provides some gas quality improvement, since Carbon Dioxide can diffuse through the water).

Because gas bubbles cause vertical mixing, which can be enhanced by the movement of the floating drum, there is a high probability that some portion of today’s input will be in the discharge area during tomorrow’s filling and get pushed out with very little treatment. Conversely another portion of today’s input will be circulating for weeks before being discharged (to get the average Retention time right) so is over treated and contributes little to gas production.

Chinese Fixed Dome Digester A Chinese Fixed Dome digester uses water displacement to provide gas pressure, as gas collects in the dome, it forces liquid out into a side chamber, generating gas pressure.

Construction was originally, and often still is, from concrete and masonry, but materials like steel and rigid plastics can also be used. As gas is used, liquid flows back into the digester to replace the gas volume withdrawn. For those mathematically inclined, here Pressure = Density X Acceleration of Gravity X Height, so for water Pressure (kPa) = 1000(kgm-3) X 9.8(ms-2) X Height(m). Since the liquid level in the digester goes down as gas is produced and the liquid level in the side chamber goes up as liquid is transferred the Height difference will change during production/use of biogas, and so the supply pressure will also change.

Not only do gas bubbles drive mixing in a Chinese Fixed Dome digester, the movement of liquid in the dome also helps break up any crust that may form, and enhances mixing. This means that some fresh material is pushed into the side chamber, releasing odors and allowing methane (the fuel you are looking to capture) into the atmosphere, where it does about 24 times more damage than Carbon Dioxide as a Greenhouse Gas. Other types of Digesters From these three basic types of digesters many other designs have been developed, usually with the intention of improving performance. This brings me to a few more philosophical points.

When trying to achieve better “efficiency”, does your measure of efficiency correspond to what you are trying to achieve? For example, the efficiency of a digester could be quoted as either Biogas per unit Volume of Digester or Biogas per unit Volume of Influent. What you will www.biogas-india.com

probably find is that as Biogas per unit Volume of Digester increases, the Biogas per unit Volume of Influent goes down, since you are pushing effluent through faster to make better use of the reaction vessel. So, there is less time to release the harder to get methane. Maybe you were using the proposed “efficiencies” when what you were really after was a certain volume of biogas per day.

Another consideration is the total cost of improved performance. Does the increase in gas production pay for the installation, running and maintenance of the items actually creating the improvement? Related to this, does any energy required for the improvement provide a Net return, generating more energy than is used running the addition.

I’m a great believer in the KISS Principal – Keep It Simple, Stupid. In support of this idea, Albert Einstein is quoted as saying, “Things should be as simple as possible, but no simpler!”. It is my own observation that “westerners” tend to make things more complicated than is necessary by adding features and accessories to assist the user. You only need to look at a car to see this – the modern car will warm/cool you, entertain/ inform you, park and drive itself with all sorts of conveniences like central locking and proximity sensors, but still only carries out the function of moving you and your possessions from point A to point B just like a Model T Ford that didn’t even have windscreen wipers.

My observation of different anaerobic digesters has prompted me to propose what I have come to call Harris’ Law – “The harder you push any system the more unstable it becomes and the more management it requires!”. Marshes produce biogas with no human invention at all, but once humans get involved, the complexity usually increases until the point is reached where a small extra effort to improve biogas production results in failure of the system.

Now that I have got my philosophical points off my chest it is time to have a brief look at some more advanced types of anaerobic digester.

Continuous Flow Stirred Tank (CFST) Digester The Continuous Flow Stirred Tank (CFST) Digester is a development of the Indian Floating Drum digester. Some form of agitation is introduced to improve performance, usually along with heating to accelerate the digestion process and ideally input is continuous, although in many systems periods of input alternate with periods of no input because the supply of waste

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may not be continuous or pumping rates are too high.

With all the above “tank” digesters, the limit to throughput is actually the microbial growth rate, once the flow rate is such that the slowest growing microbe cannot replace itself fast enough the system fails by “Wash Out”. Various methods of retaining the microbial ecology have been developed.

Packed Bed/Attached Film Digesters One method of retaining the microbial population is to provide some growth media which the microbes can become attached to, so they don’t get washed out of the digester. There is a wide range of possible medias, including Bio Balls, timber, mesh, rocks, etc. which give rise to terms like Packed Bed and Attached Film digesters.

Sometimes the microbial growth is such that flow through the media is restricted, in which case some process of removing excess microbial growth must be employed. Particles in the influent are another problem, as they can also clog the passages and restrict flow through the digester.

effluent is used to support a flock of microbial matter with some means of retaining the flock particles, so not too much microbial matter gets washed out of the digester.

Startup of USABs involves developing the flock, which must then be maintained at a suitable level.

Operating Temperature Mesophilic Digesters Because many of the microbes involved in Anaerobic Digestion are found in animal digestive systems (including human stomachs) they have evolved at body temperature, so Mesophilic Digesters are designed to operate in that range, typically at 35 C. In fact, some textbooks will state that operating temperature must be controlled to within one degree of the desired temperature.

Psychrophilic Digesters

Upflow Anaerobic Sludge Blanket (UASB) Digesters

Methanogens and their associated ecology are also found in the soil, termite guts and presumably reptiles and other cooler places, including the Arctic Tundra and ocean depths, at temperatures well below 35 C. Digesters that operate at ambient temperatures are called Psychrophilic Digesters, typically operating at 15-20 C.

In an UASB digester the upwards flow of

One of my students operated a 200 liter Poly

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Biogas Magazine | Edition 17 | 30

Digester outdoors in winter at Roseworthy College with ambient temperatures that result in the digester temperature ranging from 10 C to 14 C, producing a reasonable quantity of biogas.

Thermophilic Digesters Methanogenic microbes can also be found in hot places like volcanoes, so since warmer is better digesters have been run in the Thermophilic temperature range of 45 C – 55 C. Temperatures above 60 C are fatal to some of the microbes involved, so there is an upper limit.

A member of the Facebook Biogas Group who works with thermophilic digesters revealed in a conversation with me that very good control of factors like temperature and pH were needed for proper operation of his digester.

Modelling Some years ago, so far back that I cannot remember the details or if I still have the information, I did some dynamic modeling of the

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digestion process and set up a CFST and a Plug Flow model. What I noticed was that the CFST slightly outperformed the Plug Flow Digester over a narrow range of conditions, but the Plug Flow got close to peak performance earlier and continued close to peak performance for a while after the CFST had dropped away from its peak and fallen below the Plug Flow Digester output.

The plateau in performance for the Plug Flow Digester suggests to me that this type of digester may provide more robust operation over a range of conditions than the CFST Digester does.

Mr. Paul Harris Past lecturer in Agricultural Engineering

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Steverding Agitator Technology

Steverding Agitator Technology is an expert in agitators. High technology is expected today at all levels of power generation. Steverding Agitator Technology can boast more than 20 years of experience in the manufacture of agitators. The continuous optimization and analysis of our products together with constant technical innovation show best results. Today, we are partners and system component suppliers of leading biomass facility manufactures in Germany, France, United Kingdom, Lithuania and many other countries.

This is our current range of agitators from Steverding Agitator Technology:

Impressions:

Hydromixer

Spiralo®

Schwanko

Vertical agitators

Long shaft agitators

Plug-flow agitators

Gerhart-Hauptmann-Str. 41, 48703 Stadtlohn, Germany +49 2563 - 2088841 www.biogas-india.com

@

info@rt-st.com

www.rt-st.com

Markus Graute

Biogas Magazine | Edition 17 | 32

Steverding Agitator Technology • Gerhart-Hauptmann-Str. 41 • 48703 Stadtlohn • Germany

Crossword Puzzle 6.0

ACROSS

TOP DOWN

1. The Methanogens falls under this domain of single celled microorganisms which has structure almost similar to bacteria.

2. This property provides the buffer capacity (tendency to resist acidification) of a solution/substrate.

4. I am definitely needed to kick start the digestion process.

3.Measuring me will gauge the degree of dryness of cleaned biogas.

5. Operating reagents used to achieve higher solid separation from slurry during phase separation process.

The reagent creates an agglomeration of the particles contained in the digestate, and thus improves the phase separation. (Word begins with “F”).

6. The stable carbon compounds contained in the digestate,over a period of time,sustainably enrich the _________ content in the soil.

It contributes to improvement in microbiological activity, and retention of moisture and nutrient content in soil.

Please send your answers to info@biogas-india.com to win attractive prizes. Answers to be published in the next edition of magazine.

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Biogas Magazine | Edition 17 | 33

Low Cost and scalable Micro digesters

Compressed Biogas (CBG) Potential from Agricultural Residues – an Indian Perspective

I

ndia currently relies heavily on crude oil imports (about 80% of its total oil requirement) and LNG to power its economy (approximately 55 percent of its total natural gas demand). Such a high level of energy reliance necessitates the exploration of other “home-grown” possibilities and strengthening of the country’s energy security. With 168 million hectares of fertile land, India is second only to the United States in terms of agricultural land use. Despite the fact that India’s manufacturing and service sectors are booming, the agricultural sector

Gas Upgradation facility

Bioslurry treatment unit

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still contributes only about 15% of the country’s GDP (gross domestic product). Nevertheless, it still is a source of subsistence/employment for more than half of India’s population, and thus, the backbone of India’s economy.

Insights into India’s Agricultural Sector

As a result, there is a significant amount of trash created in the form of post-harvest crop leftovers at this level of agricultural activity.

While the present techniques in India for using crop wastes in various forms are covered below, it is important to note that the future of India’s bioenergy or biofuel programs largely revolves around the agricultural sector.

From the pie chart, it can be inferred that rice straw and husk (33%), wheat straw (22%), sugarcane tops and bagasse (17%), and cotton stalks (10%) account for almost 80% of crop residues. Of the remaining 20%, majority can be attributed to residues from maize, pulses (tur, gram), and oils seeds (soyabean, rapeseedmustard, groundnut, and castor crops).

Moreover, it should be noted that the top five states in terms of crop residue generation

According to the studies of IARI (Indian Agricultural Research Institute) from 2018, the share of crop residues/ biomass (on a dry basis) across few selected crops in the country is as shown below:

Fig: Percentage share of bulk crops in dry residue production

can be listed as Uttar Pradesh, Maharashtra, Punjab, Madhya Pradesh, and Gujarat. For the year 2019, according to MNRE (Ministry of New and Renewable Energy, India), it is estimated that out of the total post-harvest crop residues, which is in the order of 682.61 million tons per annum, approximately 178 MT per annum (~26%) is surplus crop residue that could potentially be used for industrial energy. This crop surplus is estimated upon considering the various purposes for the usage of gross crop residue, particularly in the form of cattle

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fodder, recycling back to the harvested fields to replenish the soil (as a nutrient), other local usages, and existing industrial projects mapped out for crop residues. However, as per reports of CPCB (Central Pollution Control Board), a body under the direction of the Indian Ministry of Environment, around 65% of the surplus residues are burned in the fields by farmers. The reason for burning residues on-field may vary widely from region to region but it is primarily attributed to making the field instantly ready for the next crop sowing season.

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Estimating Practical Potential of Crop Residues for CBG Projects

Fig: Stepwise assessment of net practical availability of crop residues

The above pictorial representation depicts stepwise utilization of the crop residues, and eventual practical availability of surplus crop residue, possibly for CBG projects. The Technical Gross Residue Potential (GTP) corresponds to the annual amount of residue (on a dry basis) generated in the field, i.e. after harvesting crops, estimated upon totalling the gross residues of all crops. Then out of this estimated GTP, different means are demonstrated for its local usage, particularly in the form of cattle fodder, recycling back to the harvested fields to replenish soil nutrients, and its health (as recommended by DACFW, Ministry of Agriculture, for efficient crop residue management), and household purposes.

So, upon assessment of the local needs, the Net Technical Potential (NTP) of crop residues can be identified. For estimating the of individual needs, which may be very local indeed, and the statistical average possibly being misleading, it is highly recommended to canvas the opinions and experience of the relevant farmers (with a representative sample). A handful of such surveys have already been conducted across states and districts under programs of IARI, ‘Assessment towards the setting-up of biomass exchange’ organized by GIZ, to underline few salient studies.

Furthermore, out of the estimated NTP in the previous step, the Practical Potential (PP) of crop residues, shall essentially comprise the surplus of residues available upon accounting for all other existing residue usages, over and above the aforementioned local usages. The existing usages or applications of crop residues are as mentioned below: www.biogas-india.com

1. Traditional Usage - Biomass can be utilized in a variety of traditional and rural enterprises, such as a heat source for brick/ lime kilns, parboiling rice, creating charcoal, and so on, in addition to local family usage like household cooking fuel or for building and repairing thatched roofs of dwellings.

Modern Industrial Usage - The modern uses of biomass tap into the advantage of modern biomass technologies such as incineration, compaction, combustion, pyrolysis, gasification, fermentation, and anaerobic digestion. The products from these processes are ii.briquettes/ bio pellets, RDF (refuse-derived fuel), or biofuels, such as bioethanol, and biogas (CBG being an upgraded version of biogas).

Other innovative usages may include mushroom cultivation, usage as fly ash in road construction, etc.

While the traditional local usage of biomass is expected to comprise only a minuscule fraction, the emphasis should be laid upon the estimation of crop residue utilization in registered industry projects, i.e. under various government schemes for the effective industrial usage of biomass.

It’s worth noting that India’s expanding experience in generating industrial energy from biomass residues hasn’t been properly examined, and there aren’t many structure statistics/data points available on this aspect.

Yet much information is available on energy projects consuming agricultural residues or planning to do so, given that a large part of these projects applies to government-aided

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programs such as the clean development mechanism implemented via the UNFCCC (UN Climate Change Conference). Under another such assistance program, MNRE provides financial assistance for the settingup of facilities to manufacture biomass pellets, briquettes, and RDF, which in turn promotes the processing of agricultural crop residues and municipal solid waste. According to the annual reports (2019) of MNRE, 288 projects producing a total of 2665 MW with crop residues have been sanctioned to date.

In any case, greater state-level data on the distribution of these projects, presumably from MNRE records as well as relevant State Nodal Agencies (SNAs) for Energy and Agriculture, could provide a clearer understanding of the status of installed, as well as potential forthcoming initiatives. This information should help to provide a more accurate estimate of the agricultural residues currently being tapped (state-by-state) and, as a result, the current availability for processing.

A small-scale household digester

Conclusion Even though India’s bioenergy programs have not performed to the desired level, India offers immense scope for CBG production thanks to its abundant surplus crop residues. To be precise, this is in the order of 178 MT per annum (million TPA), even considering the residues mapped out for immediate local usage and other registered biomass-based industrial www.biogas-india.com

projects. Energy potential from this crop residue available in practical terms roughly translates to 18 million TPA of CBG (acc. to the Bureau of Indian Standards), which would be good enough to offset ~10 percent of India’s crude oil imports, or to replace ~80 percent of the country’s present demand for LPG (liquified petroleum gas).

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Solid waste collection bins

Decentralized solid waste based biogas plant

The effectiveness of this estimated practical crop residue potential is invariably dependent on several other factors which may be operational, social, economic, or regulatory in nature. These variables; however, have been left out of the scope of this article for the sake of simplicity.

The intent here is to realize the opportunity lying within all the unlocked potential from Indian agro-residues. This opportunity also augurs well with the targeted 10 GW (through the bioenergy route in India’s energy mix) by 2022, which has been set aside by the Government of India, as part of its NDC (Nationally Determined Contribution).

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Mr. Abhijeet Mukherjee (Program Head, IBA) Reprinted from: Biogas Journal English Issue Autumn_2021 by German biogas Association

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