Crop Residues As Energy


Carbon Neutral Commons is promoting and developing the use of agricultural waste as a renewable fuel source and as a way of keeping the carbon within it captured from the atmosphere. Our focus is on rice. Rice is the source of more than 1/5th of all calories that humans consume. Every year, farmers grow 738 million tonnes of edible rice and over 1 trillion kilos of rice husk and straw.

After harvest, only a fraction of the inedible plant matter is used for animal feed and making cement, but most of it is dumped, burned and left to rot. It releases carbon and methane back into the short-term carbon cycle.

Instead, we use technology to convert the energy in the biomass through gasification. Gasification is a process that transforms organic matter in a low-oxygen environment to produce heat, syngas and carbon-rich char. This energy can be directly used to run cookstoves, while the gas can be used for small-scale electricity generation and running agricultural equipment.

Right now most homes use LPG stoves. Unsubsidized, it costs families 39 pesos per day. Currently rice husk in the Philippines is either available for free, or sold for 1.3 peso per kilo (about US$.03).

LPG Stove vs. Rice Husk Gasifier Stove

Including the operational costs, we estimate it will cost 17 pesos per day to cook with a CNC-Belonio gasifying stove. That is less than half the cost of LPG. Including the initial purchase. This switch from fossil fuels pays for itself in just over 7 months. Consumers save, while the money they are spending stays within the local economy. We think this is a clear opportunity for entrepreneurs to manufacture and distribute stoves and to deliver rice husk from mills to consumers.

The potential scale is enormous — each year the world’s annual rice crop “waste” holds the same potential energy as over 2 billion barrels of crude oil. Using this biomass as fuel produces local direct benefit including new job opportunities, lower cost of living, and higher productivity. It also reduces the dependency on volatile oil and gas markets, while keeping money spent on fuel within the local economy.