Ewing announced planning approval Monday for a $710 million combined power-heat biomass generator at the Port of Grangemouth on the River Forth, which will generate as much as 120 megawatts of electricity -- the equivalent of the amount needed to power around 130,000 homes.
It will also be aimed at industrial users with 200 megawatts thermal of heat, thus making "a valuable contribution to Scotland's ambitions to decarbonize electricity generation."
The plant, expected to be up and running by 2017, will create 70 permanent jobs and up to 500 during the three-year construction phase.
The energy minister also said it would be supplied only with environmentally certified wood fuel not linked to deforestation.
Environmentalists have raised objections over the effects of large-scale biomass generators on shrinking global biodiversity, international deforestation, air pollution, human rights and other concerns.
"In consenting [to] this application I have put in place a series of conditions to protect local residents from inconvenience, safeguard the appearance of the area, and protect the environment and air quality," Ewing said.
"The conditions to the consent also ensure that the fuel used in the biomass is from sustainable and responsible sources."
The massive plant is one of a series of four such biomass generators once proposed in Scotland by Forth Ports Ltd. and SSE PLC, with others originally slated for the ports of Leith, Dundee and Rosyth.
The joint venture company Forth Energy says the projects represent a $1.7 billion investment in renewable energy to produce as much as 300 megawatts of electricity and 260 megawatts thermal of heat.
Wood fuel, it says, "is safe and dependable and provides a source of energy which can be constantly generated."
But plans for the Leith plant were shelved last year after strong opposition from opponents, who claimed the government is backing away from a pledge to use local fuel sources for biomass generation and instead has opted for large-scale efforts that require the importation of masses of trees.
In 2011, seven people were arrested during a protest against the power station at the Grangemouth docks after about 20 protesters blocked access roads to the port and locked themselves to scaffolding tripods, the BBC reported.
"[The government] claims to have a policy favoring use of biomass in small-scale plants, off the gas grid, using primarily local sources of supply," Friends of the Earth Scotland Director Richard Dixon told the broadcaster.
"Now it approves a massive power station importing over a million tons of trees a year to burn for electricity, with no guarantee that Forth Energy will find customers for the heat it produces."
The Grangemouth approval also brought criticism from the Scottish Green Party.
Member of Scottish Parliament for Lothian Alison Johnstone told the BBC the government had "made a poor decision, and should instead be supporting genuinely sustainable heat and power at a local level.
"Chopping down swathes of foreign forest to burn in Scotland is plain daft."