The Maryland Board of Public Works unanimously approved Wednesday the first redevelopment phase of the 28-acre State Center complex on the edge of Mount Vernon.

Under the terms of the deal, the state will lease 500,000 square feet of office space slated to be developed at two new buildings in the development. The state will pay $25.85 per square foot, not including operating costs, beginning in 2014.

The approval is a key step for the private developer, led by Ekistics LLC, to seek financing for the $215 million first phase. Construction is scheduled to begin in the fall.

Phase one will encompass 500,000 square feet of office space spanning two new buildings, a parking garage, 70,000 square feet of street-level retail space, including a grocery store. A parking lot currently sits on the site.

In total, the entire redevelopment is set to take place in five phases and spans 15 years.

Over the next 20 years, state officials say phase one will generate more than $200 million in state and city taxes and another $30 million in lease payments to Maryland.

Once the entire development is complete, the state expects to be $144 million in the black by year 20. This includes a projected $28 million in parking revenue, $30 million in ground rent and shared profits, and $160 million in new state taxes over the first 20 years.