Gov.Martin O'Malley's stripped-down bill to promote the development of an offshore wind energy industry off the Maryland coast cleared several test votes in the House of Delegates Thursday and appears poised for final passage in that chamber as soon as Friday.

Republican delegates offered several amendments seeking to gut or further weaken the bill, which had already been scaled back in the House Economic Matters Committee. On each roll-call vote, the Democratic majority rejected the measures by an overwhelming margin. The House then gave the bill preliminary approval.

The key vote came on an amendment offered by Del. Ron George, R-Anne Arundel, that would have scaled back the proposed wind farm off Ocean City to one prototype turbine.

At the urging of Del. Dereck Davis, thePrince George's CountyDemocrat who chairs the committee, the House rejected the amendment on a 41-93 vote. Before that vote, Davis accepted an amendment by Del. Jeannie Haddaway-Riccio, a Middle Shore Republican, to limit the potential cost to farmers.

The bill sets a $1.50-a-month limit, measured in 2012 dollars, on the potential cost of such a project to residential customers. That represents a reduction from the $2 allowed in O'Malley's original bill.

If the bill passes the House, it still faces a battle getting through the Senate Finance Committee. It's chairman, Sen.Thomas M. Middleton, D-Charles, is supportive but it is not clear whether a majority of the panel will vote for the bill.