Rhode Island’s Building Trades Unions are urging government regulators and lawmakers to support of a proposal to build two wind farms off the Rhode Island coast.

The offshore wind farms proposed by Deepwater Wind would create high-paying jobs for years to come and could spark the creation of a clean-energy industry in Rhode Island. At the hearing in Pawtucket City Hall, they urged the Public Utilities Commission to consider the possible economic benefits as it decides whether to give a key approval to the first of the two projects.

“It’s an investment in the future,” said Michael F. Sabitoni, president of the Rhode Island Building and Construction Trades Council, an umbrella union group. “With our hopes and your vision, we will be known as the renewable, offshore wind hub of the United States.”

Sabitoni and seven others spoke in favor of the eight-turbine wind farm planned off Block Island. Nobody testified against the project, which would precede a 100-turbine project proposed for 15 miles off the Rhode Island coast.

It was the third hearing on a proposed power-purchase agreement between Deepwater and National Grid, the state’s largest electric utility. The first two hearings were held in Block Island and Narragansett. The final one will be Jan. 20.

The commission will then have evidentiary hearings in March in which energy experts will testify. A vote is scheduled for March 30.

Under the proposed deal, National Grid would pay Deepwater 24.4 cents per kilowatt hour for electricity generated by the Block Island wind farm. The price would escalate by 3.5 percent annually over the 20-year contract.

Energy from the development would go directly to Block Island, where residents pay exorbitant rates for electricity from diesel-fired generators. Excess power would be fed through an underwater cable to customers on the mainland.