* No update on timing for Keystone XL
* Says Gulf Coast project in service within weeks
* Q3 comparable profit C$0.63/shr vs C$0.59 expected
* Shares up 0.3 pct
VANCOUVER, Nov 5 (Reuters) - TransCanada Corp, which is backing the controversial Keystone XL oil pipeline, said on Tuesday its third-quarter profit rose 30 percent on stronger results from its Canadian natural-gas mainline system and its electricity operations.
The company, Canada's No. 2 pipeline operator, also said it expects to begin filling its Gulf Coast crude oil pipeline within a few weeks. Construction on the line is 95 percent complete.
"We are very close to completion and we would expect that we will be calling for first oil here probably in as early as a few weeks," Alex Pourbaix, president of TransCanada's pipeline division, said on a conference call with investors.
The Gulf Coast pipeline, which will ship oil from Cushing, Oklahoma, to the Gulf Coast, is the southern leg of the Calgary-based company's controversial Keystone XL pipeline.
The line will have a capacity of 700,000 barrels per day when complete and could be expanded to more than 800,000 bpd, with 2014 flow expected to average 550,000 bpd, Pourbaix said.
TransCanada's shares were up 0.3 percent at C$47.04 early afternoon on the Toronto Stock Exchange.
The Calgary-based company is still awaiting a presidential permit for the northern leg of the Keystone XL crude oil line.
The company did not say when it expects a decision from the Obama administration, but said the delay, which has stretched on for five years, would add to the project's $5.3 billion budget. Once a permit is issued, it said the project could be in service within two years.
Keystone XL, fiercely opposed by environmental groups, could carry more than 800,000 barrels per day of crude oil from Alberta to U.S. refineries on the Gulf of Mexico coast, providing relief for Canadian oil producers worried about tight pipeline capacity.
The company said it has spent $2 billion on the project, as of Sept. 30.
Net income attributable to common shares rose to C$481 million ($462.1 million), or 68 Canadian cents per share, from C$369 million, or 52 Canadian cents per share, in the year-prior quarter.
Comparable earnings, excluding most one-time items, rose 28 percent to C$447 million, or 63 Canadian cents per share. On that basis, it beat the average analyst estimate of 59 Canadian cents, according to Thomson Reuters I/B/E/S.
TransCanada's earnings beat was driven by strong results from its power operations and its Canadian Mainline pipeline, though partially offset by challenges in its U.S. natural gas pipeline business and cyclical lows in its gas storage business.
TransCanada said cash flow for the quarter rose 21 percent to C$1.05 billion. The board of directors also declared a dividend of 46 Canadian cents per share for the quarter ending December 31, 2013.