While most olefins (e.g., ethylene and propylene) are currently produced through steam cracking routes, they can also possibly be produced from natural gas (i.e., methane) via methanol and Oxidative coupling routes. We reviewed recent data ill the literature and then compared the energy use, CO2 emissions and production costs of methane-based routes with those of steam cracking routes. We found that methane-based routes use more than twice as much process energy than state-of-the-art steam cracking routes do (the energy content of products is excluded). The methane-based routes can be economically attractive ill remote, gas-rich regions where natural gas is available at low prices. The development of liquefied natural gas (LNG) may increase the prices or natural gas in these locations. Oxidative coupling routes are currently still immature due to low ethylene yields and other problems. While several possibilities for energy efficiency improvement do exist, none of the natural gas-based routes is likely to become more energy efficient or to lead to less CO, emissions than steam cracking routes do. (c) 2008 Elsevier Ltd. All rights reserved.