Aug 14 (Reuters) - U.S. liquefied natural gas developer

NextDecade ( NEXT ) said on Wednesday it was exploring all

available legal and regulatory options to ensure the

construction of the first phase of its Rio Grande project in

Texas.

Earlier in August, a U.S. court had overturned the Federal

Energy Regulatory Commission's authorization for the project,

for not issuing a supplemental environmental impact statement.

NextDecade ( NEXT ) said the judicial decision would not come into

effect till the court issued a mandate, which was not expected

to occur until the appeals process had been completed.

"If the ruling stands, the precedent set impacts the

viability of all federally permitted infrastructure projects

because it will be difficult for developers to attract capital

investments until projects receive final unappealable permits,"

CEO Matt Schatzman said.

The company's flagship facility has been in development for

several years and has already suffered repeated delays.

The first phase of the project is expected to reach

completion by early 2029 at an expected cost of about $18

billion.

It is already building the first three liquefaction trains

for the proposed project, which would have the capacity to

produce about 27 million tonnes per annum of LNG, once all of

the trains become functional.

The company, which is backed by the likes of Global

Infrastructure Partners and French energy major Total Energies

, said that overall project completion of the first two

trains stands at 24.1%, as of June.

It has also received purchase orders of about 92% of total

capacity for the first two trains and 88% of the total for the

third train.

The company was planning to start construction of the fourth

liquefaction train in the second half of 2024 after a final

investment decision.