Cleaner Long-Haul Engines Guzzle Diesel or Natural Gas

Companies are developing powerful engines that can run on natural gas together with diesel.

http://www.technologyreview.com/news/519641/cleaner-long-haul-engines-guzzle-diesel-or-natural-gas/?utm_campaign=newsletters&utm_source=newsletter-weekly-energy&utm_medium=email&utm_content=20131014