Compressed natural gas clears the air in Bangladesh
Cleaner-burning fuel is reducing dangerous levels of pollution – and saving money, too.
Muhammad Mokles plies the busy Dhaka streets in his green-painted auto-rickshaw. But when it’s time to refuel, he skips the traditional gas pump and goes straight to a compressed natural gas (CNG) station. It’s not only much cheaper than gasoline but it’s also much better for the environment.Skip to next paragraph
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Here in Bangladesh’s capital, the streets overflow with thousands of noisy honking vehicles, pedestrians, beggar children, food vendors, and stray animals. Millions of people need to move around this crowded and sprawling metropolis of 11 million each day, and many do so in an auto-rickshaw that can dart around larger or slower forms of transport.
Auto-rickshaws are cheap, convenient, and in use all over Asia. Up until recently, the ones here in Bangladesh all were powered by two-stroke gasoline engines; (also found in many motorcycles and larger three-wheelers), which alone were responsible for 60 percent of all vehicle-related pollution here, according to the Asian Development Bank.
That’s because two-stroke engines don’t use gasoline efficiently. Up to 40 percent of the fuel emerges from the tailpipe unburned, as smoke and soot. Burning gasoline and diesel produces carbon dioxide, carbon monoxide, sulfur dioxide, nitrogen oxides, hydrocarbons, and soot that warm the climate, threaten human health, and pollute water, air, and soil. In Bangladesh, soot levels in 1997 were found to be 10 times higher than World Health Organization guidelines permit. This resulted in an additional 15,000 deaths and millions more illnesses, according to World Bank estimates.
Spurred by these findings, the government of Bangladesh took action in the mid-1990s to clear the air. Leaded gasoline, which can pollute groundwater, was banned in 1999. Strict regulations were placed on the sulfur content in diesel fuel. An import ban was placed on two-stroke three-wheelers to help phase out older-model auto-rickshaws, and a widespread CNG program was launched.
Compressed natural gas is “known to be a fuel with lower air pollutant emissions,” says Sameer Akbar, senior environmental specialist at the World Bank. Natural gas is 95 percent methane and releases significantly fewer tailpipe emissions than does gasoline or diesel fuel.
“The combustion of CNG does release more methane than gasoline [does], but those emissions are minor compared with the emissions released from gasoline combustion,” says Andrew Burnham of the US Department of Energy’s Argonne (Ill.) National Lab. Unburned methane itself is a powerful greenhouse gas.
Cheap fuel, expensive conversion
CNG programs work well in countries with abundant natural gas reserves like Bangladesh. Italy started using CNG in the 1930s and was the first country to put a viable program in place. Other countries now using CNG successfully include India, Pakistan, Iran, Argentina, and Brazil.
CNG has been around in Bangladesh since 1982. “At that time it wasn’t an issue of environmental concerns,” says Iftikar “Sabu” Hussain, CEO of CNG Distribution Company. Compressed natural gas was initially introduced as a domestic fuel alternative to expensive imports, but did not catch on then because converting to the cheaper fuel involved an expensive engine conversion. The increasing cost of imported petroleum, however, plus a rising concern for the environment made CNG a stronger choice in the early 2000s.