CARLSBAD — Officials with Poseidon Resources are celebrating after the California State Land Commission granted the final permit needed to build the first desalination plant of its kind in the county.

The plant will be built on the property of the Encina Power Station on Carlsbad Boulevard, and will take ocean water from the Agua Hedionda lagoon and turn it into 50 million gallons of drinking water a day.

It has been a long road to get to this point for Poseidon Resources, Inc., a company from Connecticut.

The project has been in the works since the early 1990s, Peter MacLaggan with Poseidon Resources said, and when completed will be the largest in North America.

The California Coastal Commission approved the project last fall, prompting two environmental groups to join forces and file a lawsuit against the commission for giving the desalination plant “conditional approval.”

Marco Gonzalez, an environmental attorney, said the concerns are not with the process, which is likely the wave of the future, but with the impacts this particular plant will have on the surrounding area.

The plant is expected to be up and running by 2011.