WASHINGTON - Congressional Republicans have resurrected their efforts to force speedy approval of TransCanada's Keystone XL pipeline, attempting to insert provisions aimed at greenlighting the project into legislation before both the House of Representatives and the Senate this week.

Mitch McConnell, Senate minority leader, is co-sponsoring the Republicans' Keystone XL amendment to a highway bill that's working its way through the upper chamber.

That suggests the Republicans will push for a vote on the bill soon, perhaps even later Tuesday, in the Senate, where they hold 47 of the chamber's 100 seats.

The House of Representatives, meantime, will debate a 979-page package of energy and transportation proposals in several separate pieces of legislation this week, Speaker John Boehner said Tuesday.

Splitting up the package enables "each major component of the plan to be debated and amended more openly, rather than as a single 'comprehensive' bill with limited debate and limited opportunity for amendment," he said in a statement.

The energy component of the package includes a measure that would reverse President Barack Obama's decision last month to reject the $7.6-billion pipeline that would transport oilsands bitumen from northern Alberta through six U.S. states to Gulf Coast refineries.

Renewed Republican efforts to force the pipeline's approval came as TransCanada (TSX:TRP) announced it now expects a start-up date for Keystone XL in early 2015, not 2014 as previously announced.

The company has said the delay is partly due to the fact that it's waiting for more information from the Obama administration about reapplying for a permit.

Asked about the latest Republican move, TransCanada CEO Russ Girling said the company appreciates any efforts to speed up the project's approval.

"That said, I'm not focused on what's going on there at all. Our focus is 100 per cent on things that we know how to do, which is permit and construct pipelines."

Last month, the White House rejected the Keystone XL application, saying a congressionally imposed deadline of Feb. 21 for approving the project didn't provide enough time for State Department officials to complete a fresh review of Keystone's new route around a key aquifer in Nebraska.

The State Department is involved in the process because the pipeline crosses an international border.

Obama invited TransCanada to reapply, saying the rejection had less to do with the merits of Keystone XL than it did with the deadline set by the Republicans.

It's unclear whether the Republicans would succeed this time around either, but environmentalists are fretting about their latest tactics. They're nervous Democratic senators might go along with the Keystone provisions since the transportation bill has bipartisan support.

A coalition of groups marched to the Senate in protest Monday, while 350.org also launched a 24-hour movement to deliver 500,000 email messages to the Senate to state their opposition to Republican efforts to force approval of the pipeline.

Their expectations were exceeded. By noon on Tuesday, more than 600,000 people had sent emails, and officials from several environmental groups were planning to deliver boxes containing the signatures directly to McConnell and Senate Majority Leader Harry Reid.

In New York, meantime, a group of environmentalists planned a Valentine's Day march on the office of Chuck Schumer, the senior Democratic senator of their state.

"It's time for lawmakers to start heeding people across the country who are saying no to this Big Oil project and other dirty energy projects," Susan Casey-Lefkowitz of the Natural Resources Defense Council said in a statement.

"Americans know that we can do better for our climate, water and farmlands than expansion of destructive and expensive Canadian tarsands."

Keystone XL has become a political hot potato for Obama in a presidential election year.

Opponents of the pipeline say it's an environmental disaster waiting to happen, and emblematic of America's over-dependence on fossil fuels.

Proponents say it will create thousands of jobs -- some Republicans have even suggested hundreds of thousands -- and will help end U.S. reliance on oil from often hostile OPEC regimes.

The jobs argument, however, has focused on temporary positions. It's been tempered by recent State Department findings that suggests the pipeline will create as few as 20 permanent positions once it's fully constructed and operational.

TransCanada, meantime, says hundreds of permanent jobs will result from the pipeline.