Surplus land not required by coal mining companies would either be returned to the state governments or could be used for building solar power plants, Power and Coal Minister Piyush Goyal told parliament on Monday."The government has examined the issue of amending Coal Bearing Areas (Acquisition and Development) Act, 1957 to return the mined out land and the land acquired but found to be in excess of actual requirement to the state government for utilisation after reclaiming them," Goyal told the Rajya Sabha in a written reply."Considering our efforts towards providing clean and green energy, we are also considering setting up solar energy plants on such lands," he added.He said protection of such land against encroachment and their maintenance often involves unnecessary expenditure for the state-run coal companies.The excess land can be used for projects like afforestation, renewable energy and public utility services, the minister said.