An appeals court has declined to issue an injunction blocking construction of part of a transmission corridor that will bring electricity generated by hydroelectric plants in Quebec to Lewiston, where it will be fed into the New England power grid.

The 1st U.S. Circuit Court of Appeals in Boston said late Thursday that it agreed with a federal judge in Maine who had declined to issue an injunction to block construction on part of the New England Clean Energy Connect, which will stretch over 145 miles through western Maine. The request for an injunction was included in a lawsuit filed by environmental groups who argued that the Army Corps of Engineers did not perform a complete review of the impact of the corridor on the environment when it issued permits to Central Maine Power.

The appeals court said that opponents of the project are unlikely to win in court. Injunctions are only granted if a party seeking one can convince a court that it is likely to win, along with several other benchmarks that judges consider.

The injunction covered one of the five segments of the project and would have blocked contractors from filling wetlands and building a tunnel underneath the Kennebec River. Opponents of the project said the Army Corps and Department of Energy should have completed a full environmental impact statement on the project rather than the less extensive environmental assessment that was performed.

Thorn Dickinson, president of the company formed by CMP to oversee construction of the corridor, called the ruling “a victory for Maine’s clean energy future” and said the project will replace electricity generated by fossil fuels with “clean hydropower.”

One of the groups opposing the project said it was “very disappointed” by the court ruling. But Colin Durrant, spokesman for the Natural Resources Council of Maine, said the organization would continue to press its court case, which alleges that the Army Corps and Department of Energy failed to follow the National Environmental Policy Act in issuing permits for the project.

The corridor plan also faces a potential block this fall with a referendum question that will ask voters if the Legislature should have to approve projects like the corridor. The Maine Secretary of State has already certified that the opponents have gathered enough signatures to put the measure on the ballot and the Legislature is expected to also approve a referendum on the issue.