TransCanada Corp.has filed an amended application and cost estimate for the Energy East pipeline project.

The Calgary-based company says the filing with the National Energy Board makes nearly 700 changes to the route in response to concerns about environmentally sensitive areas.

"We're addressing those concerns, whether it be the types of water crossings, the technologies we use in terms of horizontal directional drilling, to make the demonstration that we are listening and that we are intent on building the safest and most reliable project possible," said company spokesman Tim Duboyce.

The proposed pipeline would take Alberta crude to an Irving Oil refinery in Saint John, New Brunswick.

The project would include the existing TransCanada pipeline as far east as Montreal plus new pipeline through Quebec.

TransCanada already signalled last month that it was prepared to make changes to the Energy East proposal, when it confirmed there would be no export terminal built in Quebec due to opposition to the environmental risks.

The project had been estimated to cost $12 billion but TransCanada now estimates the cost at $15.7 billion — not counting the value of existing pipeline assets that will be used for part of Energy East.

If the NEB gives approval, the company would like to start construction in 2018 and have the pipeline in service in 2020.

Calgary Mayor Naheed Nenshi weighed in on the issue on Wednesday, calling on government officials to get on with approving both Energy East and the Northern Gateway pipelines.

"Certainly I appreciate what the federal and provincial governments are trying to do, but I also remind them that there are two pipelines that are entirely within federal jurisdiction to approve," he said.