Rice straw to biogas (R2B) project

Unlike rice husks (that cover the grain), rice straw (stems and leaves) is left in the field after harvest and few major uses have been identified, so more than 300 million tonnes of it are simply burned each year as waste. To date, attempts to profitably collect and use this vast resource for clean energy have almost all failed. In this concept note, a consortium of leading experts outline their bold plan to be leaders in this emerging field and provide a route to clean, affordable, reliable energy for the world's 200 million small-scale rice farmers.
Innovation: The novel approaches outlined here are designed systematically to overcome the four key barriers identified in the 3 year, UK-funded 'Rice Straw Energy project', which is now ending (September 2016). The barriers are: logistics of straw collection; rice straw fuel characteristics; lack of proven business models and policy support. The respective innovations to overcome them are: a simplified, village-scale supply chain that minimises collection costs and storage; a low-cost 'dry' anaerobic digestion technology appropriate for developing countries; packaged in an innovative business model with support from public funding to reduce the risks.

This proposal seeks to address the energy trilemma by developing a route to making affordable, clean fuel from rice straw in developing countries. The technology to be used is anaerobic digestion, which is an established technology but using rice straw as the main feedstock is still an underdeveloped application for it. The focus is on industrial research to develop and test innovative new systems, sub-systems and components for producing biogas from rice straw in a more cost-effective way. This proposal for "Renewable Energy - biomass and energy from waste" seeks to addresses the energy trilemma as follows:
ENERGY ACCESS / SECURITY OF SUPPLY. Rice straw is one of the most abundant biomass resources in developing countries and small-scale rice farmers are among the poorest of the poor. Hence, being able to turn rice straw into clean fuel would significantly increase their access to clean energy. Rice is the world's number one food crop, and for every kilo of grain eaten, a kilo or more of straw is produced, so there is secure of supply of potential fuel, most of which is currently being burned as waste. As a storable fuel, biogas can provide reliable backup power for other renewables, including on calm days without wind power or at night when there is no sunshine for solar PV. However, the main target use in this proposal is as cooking fuel, because almost 50% of the population of SE Asia still relies on solid fuel for cooking, often involving collection risks for women.
AFFORDABILITY. This proposed work aims to greatly reduce the cost of rice straw biogas production through:
a) A streamlined, one-step collection and transport supply chain; b) Localised 'village-scale' production to minimise transport costs but still allow economies and specialisation; c) A novel, low-cost 'dry' anaerobic digestion technology; and c) 'Cascading' use of biomass to maximise value from the straw and the digestate as fertiliser. It will also trial a business model that could benefit small-scale rice farmers in remote areas where fuel costs are especially high but rice straw is abundant.
CLEAN. As a cooking fuel, biogas offers attractive GHG emissions savings compared to LPG, and local emissions savings compared to wood or charcoal. Indeed, cooking with solid fuels is one of the five biggest killers in developing countries, causing 4.3 million premature deaths per year. In addition, producing biogas from rice straw can help reduce pollution from inefficiently burning straw as waste, giving a double saving in environmental emissions and health benefits.
Key members of the IRRI-SUPERGEN 'Rice Straw Energy Project' team have created this commercial proposal to immediately combine that knowledge with leading innovations to help unlock the potential of this vast resource.