Nov 4 (Reuters) - Energy Transfer LP is growing its natural gas liquids (NGL) and liquefied petroleum gas (LPG) systems, company executives said on Wednesday, as it fights a legal battle to keep its Dakota Access oil pipeline running and faces the prospect of a Biden presidency.

The Dallas-based pipeline and storage company said it expects to invest three-quarters of its roughly $3.3 billion in growth capital for the year on its systems to transport NGL and LPG, both used in petrochemical production, as well as refined products.

"There is an enormous market, both domestically and around the world for petrochemicals," Tom Long, the company's chief financial officer, said on an earnings call. "That's going to be a huge growth area for us."

Energy Transfer's NGL transportation volumes rose to 1.5 million barrels-per-day (bpd) in the three months ending Sept. 30, an increase of 10% from the same period last year, the company said. It also plans to ramp up its LPG export capacity to 500,000 bpd from its current 180,000 bpd.

Meanwhile, crude oil volumes fell on its 557,000 bpd Dakota Access Pipeline (DAPL), the company said without specifying an amount.

DAPL moves about 40% of the oil produced in the Bakken, the second-largest U.S. shale basin, from North Dakota to Patoka, Illinois. Regulators last month approved a plan to double the amount of oil that can flow through the pipeline.

Energy Transfer is battling to keep DAPL operating as it appeals a U.S. district court ruling requiring an extensive environmental review of the line and vacating one of its key permits.

An appeals court is now considering whether or not to uphold the lower court's decisions.

Adding uncertainty to the pipeline's future is the possibility that Democrat Joe Biden will win the presidency and issue an executive order forcing DAPL to shut. (Reporting by Laila Kearney; Editing by Sonya Hepinstall and Stephen Coates)