Portlands Energy Centre Signs Accelerated Clean Energy Supply Contract

    TORONTO, Sept. 18 /CNW/ - (TSX: TRP) (NYSE: TRP) Portlands Energy Centre
L.P. today announced that it has signed a 20 year Accelerated Clean Energy
Supply (ACES) contract with the Ontario Power Authority for the Portlands
Energy Centre (PEC), a 550 megawatt high-efficiency, combined cycle natural
gas generation plant to be constructed in downtown Toronto. PEC is a limited
partnership of Ontario Power Generation Inc. and TransCanada Energy Ltd., a
wholly owned subsidiary of TransCanada Corporation.
    The ACES contract is the outcome of negotiations initiated in February
2006. PEC completed the applicable environmental assessment process as
confirmed by the Ontario Ministry of Environment in April 2005 following two
years of extensive studies, expert reviews, applications and public
consultation.
    The capital cost of PEC is estimated to be approximately $730 million.
PEC is expected to create more than 500 construction jobs during the peak
building period and about 25 full time positions.
    PEC will be operational in simple cycle mode and delivering 340 megawatts
of electricity to the city to meet peak summer demand beginning June 1, 2008.
When completed in the second quarter of 2009, the plant will provide up to 550
megawatts of power in combined cycle mode under the ACES contract - which is
about 25 per cent of central Toronto's needs. Visit
www.portlandsenergycentre.com.

    About TransCanada

    TransCanada is a leader in the responsible development and reliable
operation of North American energy infrastructure. TransCanada's network of
more than 41,000 kilometres (25,600 miles) of pipeline transports the majority
of Western Canada's natural gas production to key Canadian and U.S. markets. A
growing independent power producer, TransCanada owns, or has interests in,
approximately 7,000 megawatts of power generation in Canada and the United
States. TransCanada's common shares trade on the Toronto and New York stock
exchanges under the symbol TRP.

    About Ontario Power Generation

    Ontario Power Generation Inc. is an Ontario-based electricity generation
company whose principal business is the generation and sale of electricity in
Ontario. Our focus is on the efficient production and sale of electricity from
our generation assets, while operating in a safe, open and environmentally
responsible manner.

    Note: All financial figures are in Canadian dollars unless noted
otherwise.

    Legal Notice - Forward Looking Information for TransCanada
    Certain information in this news release is forward-looking and is
subject to important risks and uncertainties. The results or events predicted
in this information may differ from actual results or events. Factors which
could cause actual results or events to differ materially from current
expectations include, among other things, the ability of TransCanada to
successfully implement its strategic initiatives and whether such strategic
initiatives will yield the expected benefits, the availability and price of
energy commodities, regulatory decisions, competitive factors in the pipeline
and power industry sectors, and the current economic conditions in North
America. For additional information on these and other factors, see the
reports filed by TransCanada with Canadian securities regulators and with the
United States Securities and Exchange Commission. TransCanada disclaims any
intention or obligation to update or revise any forward-looking statements,
whether as a result of new information, future events or otherwise.

For further information: Portlands Energy Centre, Ted Gruetzner, (416)
592-3867; TransCanada, Jennifer Varey/Shela Shapiro, (403) 920-7859, (800)
608-7859; OPG, John Earl, (416) 592-4008, (877) 592-4008; Investor & Analyst
Inquiries: TransCanada, David Moneta/Myles Dougan, (403) 920-7911