A: The project could produce up to 180,000 barrels of oil a day, according to the company — about 1.5 per cent of total US oil production. But in Alaska, Willow represents the biggest oil field in decades. Alaska Republican US Sen. Dan Sullivan said the development could be “one of the biggest, most important resource development projects in our state's history". On average, about 499,700 barrels of oil a day flow through the trans-Alaska pipeline, well below the late-1980s peak of 2.1 million barrels. ConocoPhillips Alaska had proposed five drilling sites as part of the project. The US Bureau of Land Management in early February identified up to three drill sites initially as a preferred alternative, which ConocoPhillips Alaska said it considered a viable option. But the US Interior Department, which oversees the bureau, took the unusual step of issuing a separate statement expressing “substantial concerns” with the alternative and the project. The alternative showed extracting and using the oil from Willow would produce the equivalent of more than 278 million tons (306 million short tons) of greenhouse gases over the project's 30-year life, roughly equal to the combined emissions from 2 million passenger cars over the same time period. It would have a roughly 2 per cent reduction in emissions compared to ConocoPhillips' favored approach.