Limited frack supply could hamper U.S. crude oil output

Fossil fuels — coal, oil and natural gas, primarily — remain the dominant energy sources for much of the world, with their accompanying infrastructure of mines, drilling and production wells, pipelines and various forms of transportation. But they have become more problematic as governments struggle to address climate change and pivot to energy sources that do not result in carbon dioxide emissions.

While electric-powered vehicles may be the ride of the future, oil remains at least for now the dominant fuel for transportation around the world. And after a period of time at the end of the 20th century when oil was subject to wide fluctuations in price, new supplies in North America as a result of non-conventional recovery techniques have helped stabilize prices.

Background on natural gas issues.