March 20 (Reuters) - Sempra Energy said on Monday its unit has reached a final investment decision (FID) for Phase 1 development of the Port Arthur liquefied natural gas (LNG) export plant in Texas.

It has also agreed to sell an indirect stake in the project to KKR & Co Inc.

Sempra estimates the total capital expenditure for the 13.5-million tonnes per annum (MTPA) plant's Phase 1 at $13 billion.

Under the agreement, an infrastructure fund managed by KKR will buy a 25% to 49% indirect, non-controlling interest in the project. Sempra's unit, Sempra Infrastructure Partners, would target 20% to 30% of indirect ownership interest in the project, subject to the closing of the KKR sale.

The 70%-owned unit of Sempra has also finalized its joint venture with ConocoPhillips.

ConocoPhillips has acquired a 30% non-controlling interest in the project through the joint venture. The oil producer also agreed to purchase 5 MTPA of LNG from the project under a 20-year deal in November last year.

Along with ConocoPhillips, buyers of Port Arthur LNG include units of Poland's Polski Koncern Naftowy Orlen SA, INEOS, ENGIE and Germany's RWE AG.

(Reporting by Ankit Kumar; Editing by Shilpi Majumdar)