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TransCanada Launches Binding Open Season for Keystone Pipeline System Extension to Houston

CALGARY, Alberta – August 15, 2011 – TransCanada Corporation (TSX, NYSE: TRP) (TransCanada) today launched a binding open season to obtain firm commitments from interested parties for the Keystone Pipeline System to transport crude oil from Hardisty, Alberta to Houston, Texas.

The proposed Keystone Houston Lateral would involve an expansion of capacity and construction of an approximate 80 kilometer (48 mile) pipeline extension from the proposed Keystone XL system to the Houston refining center. The proposed facilities would double the U.S. Gulf Coast refining market capacity accessible from the Keystone Pipeline System to over four million barrels per day by providing access to the key refining market in the Houston area.

"The extension of the Keystone Pipeline System would provide direct access to the Houston refining market and further enhance the connection of a secure, growing and reliable supply of Canadian crude oil and domestic U.S. crude oil from the Williston basin and Cushing through Keystone Marketlink with the largest refining market in North America," said Russ Girling, TransCanada president and chief executive officer. "The addition of a Houston lateral would increase the markets accessible from the Keystone Pipeline System and provide additional flexibility to our shippers.”

Following the completion of the open season, which closes at 12 p.m. (Mountain) on October 17, 2011 and subject to receipt of sufficient contractual commitments from shippers, TransCanada intends to proceed with the necessary Canadian regulatory applications for approvals to construct and operate the facilities required for the capacity expansion and provide transportation services from Hardisty to Houston.  The Keystone Houston Lateral and capacity expansion are included in the original scope of the Keystone XL U.S. Presidential Permit application process, which is expected to conclude by the end of 2011. Subject to the receipt of the Keystone XL Presidential Permit, transportation service to Houston on the Keystone Pipeline System is expected to begin in 2014.

Keystone XL is a proposed 1,700 mile pipeline that would expand the existing Keystone system and deliver crude oil to refineries in the U.S. Midwest and the Gulf Coast.  Keystone would increase U.S. energy security by providing Americans with a stable, secure supply of U.S. domestic and Canadian oil versus continuing to import unstable, higher priced crude from the Middle East and Venezuela.  Keystone would create 20,000 American jobs during construction, inject $20 billion into the U.S. economy and pay over $5 billion in property taxes over the lifetime of the project.

Parties are invited to visit www.transcanada.com/houstonlateral.html or contact oil_pipelines@transcanada.com, Ed Scheibelhut at 403.920.2746 or David Diakow at 403.920.6019 for more information.

With more than 60 years experience, TransCanada is a leader in the responsible development and reliable operation of North American energy infrastructure including natural gas and oil pipelines, power generation and gas storage facilities. TransCanada's network of wholly owned natural gas pipelines extends more than 57,000 kilometres (35,500 miles), tapping into virtually all major gas supply basins in North America. TransCanada is one of the continent's largest providers of gas storage and related services with approximately 380 billion cubic feet of storage capacity. A growing independent power producer, TransCanada owns, or has interests in, over 10,800 megawatts of power generation in Canada and the United States. TransCanada is developing one of North America's largest oil delivery systems. TransCanada's common shares trade on the Toronto and New York stock exchanges under the symbol TRP. For more information visit: www.transcanada.com.

Forward-Looking Information
This news release may contain certain information that is forward looking and is subject to important risks and uncertainties. The words "anticipate," "expect," "believe," "may," "should," "estimate," "project," "outlook," "forecast" or other similar words are used to identify such forward-looking information. Forward-looking statements in this document are intended to provide TransCanada securityholders and potential investors with information regarding TransCanada and its subsidiaries, including management's assessment of TransCanada's and its subsidiaries' future financial and operations plans and outlook.  Forward-looking statements in this document may include, among others, statements regarding the anticipated business prospects, projects and financial performance of TransCanada and its subsidiaries, expectations or projections about the future, and strategies and goals for growth and expansion.  All forward-looking statements reflect TransCanada's beliefs and assumptions based on information available at the time the statements were made. Actual results or events may differ from those predicted in these forward-looking statements. Factors that could cause actual results or events to differ materially from current expectations include, among others, the ability of TransCanada to successfully implement its strategic initiatives and whether such strategic initiatives will yield the expected benefits, the operating performance of TransCanada's pipeline and energy assets, the availability and price of energy commodities, capacity payments, regulatory processes and decisions, changes in environmental and other laws and regulations, competitive factors in the pipeline and energy sectors, construction and completion of capital projects, labour, equipment and material costs, access to capital markets, interest and currency exchange rates, technological developments and economic conditions in North America. By its nature, forward looking information is subject to various risks and uncertainties, which could cause TransCanada's actual results and experience to differ materially from the anticipated results or expectations expressed. Additional information on these and other factors is available in the reports filed by TransCanada with Canadian securities regulators and with the U.S. Securities and Exchange Commission (SEC). Readers are cautioned to not place undue reliance on this forward looking information, which is given as of the date it is expressed in this news release or otherwise, and to not use future-oriented information or financial outlooks for anything other than their intended purpose. TransCanada undertakes no obligation to update publicly or revise any forward looking information, whether as a result of new information, future events or otherwise, except as required by law.

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Media Enquiries:  
Terry Cunha/Shawn Howard   
403.920.7859
800.608.7859

Investor & Analyst Enquiries:  
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