The City of Portland is getting a $2.5 million federal grant to include geothermal heat in its major expansion project for the Portland International Jetport. The low-emission heating system will help improve air quality for passengers and airport employees while reducing the use of conventional fuels. The city broke ground last week on the $75 million expansion that is slated for completion in 2012. The project will add three new gates, double the number of security lines and attract more airlines to the airport to support growing passenger traffic. See video below for a week-by-week-preview.