Crop waste to biogas and renewable natural gas

Innovation pathway relevant to

  • Biofuel companies
  • Farmers
  • Mechanical engineers
  • Microbiology professionals
  • Anaerobic digester manufacturers

Background & introduction

The world produces hundreds of millions of tons of agricultural by-products every year that are considered “waste” - plant stalks & roots, leaves, nut shells, fruit waste and more.

A large part of these supposed waste can actually be converted to valuable products.

One of the valuable products that can be derived from plant waste is biogas or renewable natural gas, a gas with properties similar to LPG and CNG, and can be used as a fuel in household and commercial cooking, industrial heating and transport.

What are the key sustainability benefits?

Unused agricultural waste gets converted to CO2 if burnt on the fields or into methane if left to rot. Both CO2 and methane are greenhouse gases and thus converting these to renewable natural gas through closed loop processes can significantly reduce the net greenhouse emissions from these.

An equally important benefit is the economic benefit to the society in the form of higher incomes for the farmer community. What was earlier wasted and was considered a nuisance can today provide them with substantial increases in their overall incomes.

How does this work?

Most agricultural waste is in the form of what is called lignocellulosic material - that is, the cellulose is bound by lignin, a glue-like material.

In order to convert this into biogas, the cellulose needs to be first separated from lignin (in a process called pre-treatment). The cellulose is then treated in an anaerobic digester using methanogenic microorganisms to produce biogas. This biogas is then scrubbed and upgraded to renewable natural gas which can be stored in cylinders and sold. For optimal, C/N ratio, the agricultural waste can be co-digested with other organic wastes such as food waste, animal manure etc.

Keywords

  • Biogas
  • Waste to Energy
  • Renewable natural gas

Knowledge resources

Biogas: Converting Waste to Energy

Link

Renewable Natural Gas Production

Link

Renewable Natural Gas from Agricultural-Based AD/Biogas Systems

Link

A case study on integrating anaerobic digestion into agricultural activities in British Columbia: Environmental, economic and policy analysis

Link

An overview of Renewable Natural Gas from Biogas

Link

Working of a biogas plant

Link

Biogas from agri landfills

Link

Updates

Ontario creates opportunity for boost in agricultural renewable natural gas production

The new rules are designed to introduce new ways for farmers to expand the emerging biogas and renewable natural gas market in the province

Link

ATCO to Build its First Renewable Natural Gas Production Facility

RNG is a renewable fuel produced by capturing methane emissions which would otherwise be released to the atmosphere

Link

New Research Project to Develop Optimized Biogas from Bacteria

Aiming to develop natural and synthetic microbial communities for the production of optimized biogas

Link

Egypt: Kuwait finances the conversion of organic waste into biogas in Suhag

The project will create 61 biogas units, including 57 units to convert household waste, three for agricultural schools and a mobile educational unit to be installed at Suhag University

Link

New Opportunities to Convert Biomass “Waste” to Renewable Methane and Green Hydrogen

These technologies allow for the conversion of dense, low-moisture organic material into valuable renewable gas and biochar, creating new opportunities to manage forests, agricultural waste and other hard-to-handle organic feedstocks

Link

Canada greenlights new resources for farmers who want to discover biogas

They discussed the benefits of biogas, how biogas installments work, and the educational resources available through the CBA's new website

Link

Harnessing Biogas to grow a value chain for farmers

The grant allows C-CHANGE to develop profitable methods to transition land usually devoted to annual crops to renewable energy production with native grasses

Link

Biogest Builds Two More Biomethane Plants in France

Biogest has received an order to build two biomethane (Renewable Natural Gas – RNG) plants utilfising agricultural waste and by-products from chicken farmers in the western region of France

Link

Praj Industries unveils new tech to produce biogas from biomass

Link