Building the new plant at Carmelite in Co Tipperary will be a $9.5bn investment.
The Department of the Environment said it was a “significant project” with a “high risk” of damage.
Construction of a new power station in Co Louth will be worth €1bn over 10 years.
The project will also include a new road to connect the coal-fire plant with the city.
The Government has pledged to pay for the work by selling bonds.
There are concerns that the plant could be over-reliant on coal for electricity and a recent study found that climate change would make the plant less environmentally friendly.
However, the Department of Energy said the project would not impact on any of the other renewable energy sources in the area.
The new power plant will be the largest ever installed in Ireland, with more than 6,000 megawatts (MW) of capacity.
It will be built in two phases, with the first phase of construction starting next year and the second in 2022.
The plant will also have a carbon capture and storage facility.
The €9.6bn plant will require a total of 9,500 tonnes of cement, 6,700 tonnes of limestone and 2,400 tonnes of concrete to be laid.
Construction was completed on a two-metre-high concrete wall at the site.
It is expected to be completed in 2021.
Construction will be financed through bonds issued by the Department for Energy and Climate Change.
A report by the European Commission found that the cost of the plant would be lower than expected and that the emissions reduction benefits would outweigh the costs.
Construction would be funded through the Renewable Heat Incentive scheme.
It has already attracted about €2bn in government funds and €1.5 billion from the European Investment Bank.