An unfinished nuclear plant will be altered for gas.

The unfinished Midland nuclear power plant, which was hit by delays and cost overruns almost from the start of construction, will be converted to a natural gas-fired plant under a $600-million contract signed by Consumers Power Co., the utility, and Dow Chemical Co. Under the project, to be known as MCV for Midland Cogeneration Venture, the plant will begin generating electricity for the utility and providing about 600,000 pounds of steam per hour to Dow by 1990, the companies said. The two companies initially were partners in the Midland nuclear power project, but their relationship soured in 1983 after Dow pulled out of the deal with the plant only 85% finished. Under the agreement, they have dropped lawsuits asking $520 million in damages from each other.