A Portland-based engineering firm has merged with Stantec Inc., a large engineering and architectural design company based in Edmonton, Alberta.

Stantec acquired Industry and Energy Associates in a private sale on Friday, bringing its holdings to five firms in Maine: two in Portland and one each in Scarborough, Topsham and Limestone. All of the acquisitions have been made since 2006.

The high cost of running a small business was becoming too great a challenge, said Ken Rogers, president of Industry and Energy Associates, who will now manage the office’s operations.

“To keep the company successful and to give our employees a good place to grow and get good benefits, merging with Stantec was the best decision,” he said.

Industry and Energy Associates has plans to work on a natural-gas project in Venezuela and a solar project in New Mexico. Last year, it brought in about $12 million in revenue.

In 2007, the firm completed a project on Ecuador’s Galapagos Islands involving the installation of three wind turbines and solar power. The project was funded partially by the United Nations Development Program.

None of the firm’s roughly 50 employees will be laid off because of the sale, said Rogers, but the three Stantec offices in this area will most likely be consolidated into one location in Scarborough.

Industry and Energy Associates’ experience in green engineering was a deciding factor in the purchase, said Alison Smith of Stantec.

The Topsham office has led the environmental permitting for nearly every wind farm in Maine, including those at Stetson, Record Hill, Rollins and Oakfield.

Stantec employs about 9,300 people in more than 150 locations in the U.S. and Canada.

Staff Writer Stephanie Hardiman can be contacted at 791-6301 or at: shardiman@mainetoday.com