Sustainable Energy

Cleaner Vehicles by the Million

Last January, for the first time, more cars were sold in China than in the United States. India’s vehicle fleet is growing at a rate of 7 to 10 percent per year. Instead of attempting to reduce greenhouse-gas emissions with expensive technologies such as electric vehicles, low-income countries in the Asia-Pacific region are focused on improving existing internal-combustion engines.

Converting cars to run on natural gas is an increasingly popular option. Of the 9.6 million natural-gas-fueled vehicles worldwide, 52 percent are in Asia-Pacific countries, with two million in Pakistan alone. A factory-built natural-gas vehicle can achieve reductions in carbon dioxide emissions as great as 25 percent, but most of the cars running on natural gas in this region are not quite as clean, because they have been converted from gasoline using after-market kits. Still, these converted vehicles emit half as much nitrous oxide as gasoline-fueled vehicles and three-quarters as much carbon monoxide. Conversion kits cost between $850 and $2,500, but conversion reduces driving costs because natural gas is cheaper than gasoline or diesel. The number of natural-gas vehicles has been growing at an annual rate of 40 percent over the last five years, according to the Asia Pacific Natural Gas Vehicles Association.

Asia is also home to more than 50 million vehicles powered by two-stroke engines, such as motorcycles and taxis. Per mile, each one produces as much in hydrocarbon and particulate emissions as 30 to 50 modern four-stroke automobiles, according to Bryan Willson, a professor of mechanical engineering at Colorado State University. The nonprofit Envirofit has developed a $300 fuel-injection kit that increases fuel efficiency by 35 percent and reduces hydrocarbon emissions by 89 percent. Owners can purchase the kit with microloans, and reduced fuel bills mean it pays for itself in six months.

Become an MIT Technology Review Insider for in-depth analysis and unparalleled perspective.

Subscribe today

Uh oh–you've read all of your free articles for this month.

Insider Premium
$179.95/yr US PRICE

More from Sustainable Energy

Can we sustainably provide food, water, and energy to a growing population during a climate crisis?

Want more award-winning journalism? Subscribe to Insider Basic.
  • Insider Basic {! insider.prices.basic !}*

    {! insider.display.menuOptionsLabel !}

    Six issues of our award winning magazine and daily delivery of The Download, our newsletter of what’s important in technology and innovation.

    See details+

    What's Included

    Bimonthly home delivery and unlimited 24/7 access to MIT Technology Review’s website.

    The Download. Our daily newsletter of what's important in technology and innovation.

/
You've read all of your free articles this month. This is your last free article this month. You've read of free articles this month. or  for unlimited online access.