Two environmental groups are taking the Alberta Utilities Commission to court over an expansion at a coal-fired power plant in west central Alberta.

The provincial utilities regulator has given the H.R. Milner plant, operated by Maxim Power Corp. near Grande Cache, interim approval to expand. The company has a 150 megawatt coal-fired facility now and wants to expand to 500 megawatts.

Ecojustice and the Pembina Institute are seeking leave to appeal that decision to the Alberta Court of Appeal.

Barry Robinson, a lawyer with Ecojustice, said the company asked for approval to get ahead of greenhouse gas regulations that are proposed to come into effect in 2015.

"There was no hearing, there was a notice of the application. There were some people, and some groups such as Pembina Institute, that sent in letters of concern, but the utilities commission decided no one was adversely affected by this application, which is the test that they apply, and therefore there was no hearing on this approval."

Jim Law, a spokesman for commission, said the interim approval was not speeded up.

He said was a fair and transparent process and that the application has been in the process for several years.

When final approval is made in a week or so there might be some conditions attached, he said.

Alberta has 11 coal-fired plants, more than any other province in the country.