A subsidiary of Des Moines-based MidAmerican Energy Holdings Co. has entered into a joint venture with Renewable Energy Systems Canada Inc. to sponsor a competitive proposal for the East-West Tie Line, an electric transmission project in Ontario. The subsidiary, MidAmerican Transmission, has invested in transmission in several regions in the U.S. and is evaluating opportunities to further develop electric transmission facilities in the United States and Canada, MidAmerican Energy said in a release. Earlier this month, MidAmerican announced a strategic partnership with Canadian utility company TransAlta Corp. to develop natural gas-fueled generation projects in Canada. Click here to read this story.