The Alberta government has filed its request for intervener status with the Federal Court of Appeal in the legal challenge to the approval of the Kinder Morgan Trans Mountain expansion pipeline.

The $6.8-billion project, which would double an existing pipeline running from Edmonton to Burnaby, B.C., was approved by the National Energy Board in May 2016.

The federal cabinet gave its blessing last November.

Sixteen groups including the cities of Vancouver and Burnaby, the Squamish Nation, the Coldwater Indian Band, the Musqueam Indian Band, the Raincoast Conservation Foundation and the Living Oceans Society have asked for a judicial review of the NEB decision.

They argue the National Energy Board did not properly look at the environmental impact of the project before granting approval.

All the reviews will be heard in a single hearing.

The Alberta government is seeking intervener status so it can file written arguments and possibly deliver oral arguments in the judicial review.

"The development of Alberta's resources is important to Alberta's economy," the government's notice of motion stated.

"Alberta is best positioned to speak to the potential impacts of this decision on Alberta's economy and market access and can offer a provincial perspective on the benefits of the project at issue that may not be expressed by either respondent, Trans Mountain or Canada."

The notice of motion states that the court's decision on the matter will have an impact on Alberta and the rest of Canada.

The Alberta government indicated in last month's throne speech it would seek intervener status in legal challenges to the Trans Mountain project.