Can Straw Provide China’s Energy Needs?

Efforts to use biomass rather than burning it in the fields could help ease China’s energy needs, displacing coal and cutting air pollution

SHANGQIU, China — This is not the equivalent of Silicon Valley. There isn’t a lab in sight or a high-tech industrial park in the area. What attracts most of the attention is a two-floor factory building with a signboard that reads “Shangqiu Sanli New Energy Demonstration.”

Still, this is a noteworthy place. It is healing one of China’s long-standing headaches.

That headache is straw, basically an agricultural waste collected from nearby farms. Workers here chop it, compress it, then heat it slowly in sophisticated, oxygen-free ovens to produce biochar, a sort of charcoal that can be used as soil amendments. What remains — two types of liquids called wood tar and wood vinegar — are removed to sealed vessels and are sold as eco-friendly pesticides and soil conditioners.

Through this, the factory produces industrial goods worth nearly $10 million per year. The process also produces a combustible gas that it converts into electricity — to run the machinery.

China has lots of straw. The nation is scrambling for ways to dispose of this agricultural waste, and companies like Shangqiu Sanli New Energy Ltd. are among a few that have succeeded. But figuring out how to scale this up remains a daunting challenge.

At the end of harvest season, China’s breadbaskets, from the Yangtze River Delta on the coast to the landlocked Sichuan Basin, turn into a sea of baled straw. In some places it can extend to the horizon.

Chinese farmers used to store straw for cooking and heating. But with their rising incomes and growing desire for an easier life, more rural families began buying coal briquettes and bottled liquefied petroleum gas instead. So they simply set fire to straw.

Burning straw is a major cause of smog. The smoky air also has a pungent odor that causes coughing and other health problems. Sometimes it even costs lives as dense, eye-smarting smoke clouds drift over roads and lead to car crashes.

Lawmakers here have tried to ban straw burning, but farmers in a hurry to clean fields for the next planting often ignore that. In places like eastern China’s Anhui province, the government sent drones aloft to identify the straw burners.

Tapping into folk wisdom

In 2005, after hearing about farmers in neighboring villages being jailed for burning straw, Lin Zhenheng, then a 48-year-old entrepreneur, decided to seek a solution.

Lin’s company, Shangqiu Sanli New Energy, first consulted farmers who have mastered the use of straw for years. Then it brought in some experts. About a year later, the company came out with a pilot facility in the heart of Henan province, one of China’s major crop-producing regions.

The facility turns straw into biochar and wood tar, cleaner-burning alternatives to diesel fuel. It also produces wood vinegar out of straw — a liquid that makes nonarable soil grow crops. The facility captures a large quantity of combustible gas from the process to meet its own energy needs and to heat a nearby hotel and a public bathroom — a popular facility in rural China.

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The company later found that its biochar can improve soil quality and its biodegradable wood tar can kill pests in farmland while doing little harm to Earth.

The discoveries have whetted Lin’s appetite for more straw business. His company now runs seven such facilities across the region and disposes of 200,000 tons of straw every year.

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