The construction of the most contested oil pipeline between Canada and the US just got delayed again

Reuters/Andrew Cullen

And in light of a fresh lawsuit in Nebraska, Transcanada, the company trying to build a pipeline from Alberta to Texas, has called for the US government to delay its review of the project.

Located deep underground and evenly mixed between sandy layers, Alberta's oil is a particularly sticky mixture of heavy crude and bitumen (semi-solid oil).

Extracting the oil is an energy intensive process that involves stripping the topsoil and pumping a noxious mixture of chemicals into the ground to separate the oil from the surrounding sand.

These chemicals are often not disposed of properly, contaminating groundwater and leaching the surrounding land of nutrients. In the process, they can also cause the wholesale destruction of important boreal forest and muskeg habitats.

TransCanada, a Canadian energy company, has sought to build a pipeline - the Keystone XL - that will transport the heavy oil directly from Alberta's oil sands to thirsty refineries on the Gulf coast of Texas.

The proposed pipeline's 1,700 mile path across the American midwest will traverse important habitat for many endangered species. If there's a spill, or any sort of issue with the pipeline, the environmental costs would be dire.

Lots of people want cheap oil, but they don't want the pipeline running through their backyard. The highly publicized back-and-forth between Transcanada, and the governments of both the US and Canada have focussed on carefully deciding the safest and most politically expedient route for the pipeline.

Recently, the Nebraskan Supreme Court approved a route for the pipeline through the state, allowing Transcanada to take private land through eminent domain. The proposed path of the pipeline crosses the Ogalla Aquifer, a large source of freshwater for the state.

Worries over contamination have galvanized local environmentalists and landowners alike. A grassroots organization of over 70 local landowners has brought a fresh lawsuit against Transcanada in order to re-open the debate about the proposed path of the pipeline, and force state officials in Nebraska to delay the decision-making process.

Unlikely to win this fight, Transcanada made a plea for a ceasefire on Monday, asking the Obama administration to suspend its review of the controversial infrastructure project that would bring heavy oil from Alberta to US refineries.

Calgary-based TransCanada Corp said it had sent a letter to the US State Department to suspend its application while the company goes through a state review process in Nebraska.

"We are asking State (Department) to pause its review of Keystone XL based on the fact that we have applied to the Nebraska Public Service Commission for approval of its preferred route in the state," TransCanada Chief Executive Officer Russ Girling said in a statement.

The news comes shortly after the White House on Monday said it still expects Obama will make a decision on whether to grant a permit to TransCanada Corp for the Keystone XL crude oil pipeline before he leaves office in January 2017.

Asked if TransCanada was asking for a delay because of concerns Obama may block the pipeline, TransCanada spokesman Mark Cooper said the company was not going to speculate on what the decision may be or when it may come.

The Keystone project faced headwinds both from a U.S. administration seen as favoring environmental protection over expanding oil pipelines and U.S. crude prices that have plunged to $50 a barrel from almost $150 when the project filed a federal application in 2008.

Thomson Reuters

A TransCanada Keystone Pipeline pump station operates outside Steele City, Nebraska

The TransCanada Corp pipeline would carry 830,000 barrels a day of mostly Canadian oil sands crude to Nebraska en route to refineries and ports along the U.S. Gulf Coast.

The pipeline has become a symbol in the larger political fight over climate change, with environmental groups arguing that stopping its construction will force producers to keep much of the heavy oil in the ground.

"TransCanada rightly sensed that the tide has turned against Keystone XL and now they're trying to delay any decision in the hopes that they can get a Republican president to approve it," said Valerie Love with the environmental group Center for Biological Diversity, who urged Obama to reject the appeal for more time.

(Reporting by Bruce Wallace; Additional reporting by; Nia Williams and Euan Rocha; Editing by Lisa Shumaker)