Both would try to solve one of the problems that the Keystone project was meant to address: the shortage of pipeline capacity for carrying oil from a main terminal in Cushing, Okla., to refineries in Texas and other parts of the Gulf Coast.  Enbridge, a Canadian pipeline company that is not involved in the Keystone project, said on Wednesday that it had bought a 50 percent interest in the Seaway Crude Pipeline, which runs from Freeport, Tex., to Cushing, for $1.15 billion from ConocoPhillips. Enbridge and Enterprise Products of Houston, the pipeline’s other owner, plan to reverse its flow next year to carry crude southward from Cushing. The pipeline is little used at the moment.  And TransCanada, the Canadian company proposing the Keystone XL project, said it might seek permission from the Obama administration to begin construction on the southern portion of the pipeline as early as January, which also would run from Cushing to Gulf Coast refineries.  The immediate problem for Canadian oil producers is a growing glut of oil in Cushing, which is currently the final destination for their production. The lack of pipeline capacity from Cushing has led to excessive stockpiles at the oil terminal.  That, in turn, has depressed the price of West Texas Intermediate, the benchmark United States crude oil, relative to Brent oil, the European benchmark, by as much as $27.88 a barrel in recent months. The heavy crude from the oil sands has sold at even lower prices than W.T.I.  “In the next two to three years, the Cushing bottleneck is the more pressing issue,” said Jackie Forrest, director of global oil at IHS Cera, an energy research firm.  The prospect of two new projects that would relieve that bottleneck sent American oil prices soaring on Wednesday. The benchmark crude rose $3.17 a barrel, closing at $102.60, the highest level seen since June.  Last week, the State Department effectively delayed the approval process for the 1,700-mile Keystone XL pipeline until after the 2012 election because of intense pressure from environmentalists, who oppose the messy process of extracting oil from oil sands, and from Nebraska lawmakers worried about a spill along the pipeline’s proposed route through the state.  In the near term, Keystone XL is not about transporting more oil from Canada’s oil sands into the United States. By many estimates, existing cross-border pipelines will not run out of capacity until sometime between 2015 and 2017.  But many refineries on the Gulf Coast are designed to handle heavier crudes like those produced in Canada, and they are looking to replace lost supplies from Venezuela, which has a tense relationship with the United States.  Keystone XL, if built, would give Canadian oil sands producers a route to the gulf. But an even quicker, though partial, solution could be the one proposed by Enbridge: modifying the existing the Seaway pipeline to flow in the opposite direction, from Cushing to the gulf.  Because the 500-mile Seaway pipeline does not cross any international borders, it will not require approval by the State Department, though it will be subject to other regulatory reviews. Brad Shamla, the vice president for market development for Enbridge, said that the process would be faster and less intense than the scrutiny given to new pipelines.  Initially Seaway will move 150,000 barrels of oil a day, but its owners plan to increase that through upgrades to 400,000 barrels a day in 2013.  Enbridge would continue to bring oil from the oil sands to Cushing through its existing cross-border pipelines, then put it into the Seaway system, Mr. Shamla said. The company also anticipates that oil from American shale fields would also travel through the Seaway pipeline.  In announcing the Seaway plan with Enbridge, Enterprise Products abandoned a plan to build a pipeline with a capacity of 800,000 barrels a day from Cushing to the gulf.  Rick Rainey, a spokesman for Enterprise, said that though Seaway would offer half the capacity, it would be in operation much sooner than any completely new pipeline. He said that Enterprise might also add a second pipe along Seaway’s route.  Ms. Forrest, the analyst, said the Seaway plan announced Wednesday would not offset the increasing flow of oil into Cushing, particularly from the oil sands. “This project itself will not help,” she said.  She added, however, that if TransCanada were to also build the portion of Keystone XL running from Cushing to the gulf, a pipeline that could move about 590,000 barrels of oil a day, the combined capacity of the two pipelines would end the glut and lead to higher prices for W.T.I.  It is not clear whether the United States government would permit the Keystone XL project to proceed in pieces.  At a news conference on Wednesday, Russell K. Girling, TransCanada’s chief executive, said work on the southern portion of Keystone would not take place until all approvals, including that of State Department, were in place.  However, Mr. Girling said that a deal reached earlier this week between TransCanada and the state of Nebraska, which will reroute Keystone XL around an environmentally vulnerable area, meant that approval for the entire pipeline could “be done on an accelerated process.”  Mark Toner, a spokesman for the State Department, said on Tuesday that the Nebraska deal had not changed the government’s timetable to reach a decision by early 2013.  The State Department said it would “evaluate what additional review is necessary” if TransCanada sought permission to build only a portion of the pipeline.
With the timing, and perhaps the future, of the Keystone XL pipeline project now uncertain, alternatives to the hotly contested project have begun emerging.