UPDATE 2-Keystone operator TC Energy beats profit estimates on pipeline strength

(Compares with estimates, adds details on oil spillage)

Nov 1 (Reuters) - TC Energy reported a better-than-expected quarterly profit on Friday, buoyed by higher volumes of crude and natural gas the pipeline operator transported.

Earnings from the company's oil-transporting liquids segment, which comprises its 590,000-barrel-per-day (bpd) Keystone pipeline system, surged more than 55% to C$491 million in the third quarter ended Sept. 30.

Though there has been a surge in oil transportation, with peer Kinder Morgan also reporting higher movement last month, oil producers in Canada are desperately in need of more pipelines as they face discounts on their product due to transportation constraints. (https://bit.ly/325Z0yr)

TC Energy, formerly known as TransCanada, has been investing heavily in the disputed 830,000 barrel per day (bpd) Keystone XL pipeline, which is expected to boost export volumes from the oil marketing hub of Alberta to U.S. refineries.

The $6 billion project has, however, faced regulatory and environmental hurdles despite backing by U.S. President Donald Trump.

Separately, in a major leak reported on Thursday, about 9,120 barrels of oil are estimated to have spilled from TC Energy's Keystone crude pipeline in Walsh County, North Dakota, the state regulator said.

The initial estimate makes it one of the biggest onshore crude spills in the past decade and the largest for Keystone, according to U.S. Pipeline Hazardous Materials and Safety Administration (PHMSA) data back to 2010.

On an adjusted basis, the Calgary-based company earned C$1.04 per share, beating the average analyst estimate of 98 Canadian cents per share, according to IBES data from Refinitiv.

However, net income attributable to shareholders fell to C$739 million, or 79 Canadian cents per share, compared with C$928 million, or C$1.02 per share, a year earlier.

TC Energy said the earnings were hit by combined after-tax losses of C$266 million from the sale of Ontario natural gas-fired power plants and certain Columbia Midstream assets.

Revenue also fell marginally to C$3.13 billion.

TC Energy also said it will invest about $1.2 billion to expand its subsidiaries NOVA Gas Transmission and Foothills Systems to connect to the GTN XPress Project announced by its limited partnership TC PipeLines LP.

(Reporting by Shradha Singh in Bengaluru; Editing by Shinjini Ganguli)