Hundreds of jobs would be created by building biomass power plants at four Scottish ports, Forth Ports have said.
Forth Energy, a partnership between Forth Ports and Scottish and Southern Energy (SSE), wants to create plants at Dundee, Rosyth, Grangemouth and Leith.
The biomass stations could produce a total of 400MW of power.
The group said it would use sustainably sourced wood, by-products of the forestry industry and reclaimed timber to generate the electricity.
The energy would be used to power the ports, but could also be exported to the national grid.
Forth Ports said the developments would improve the security of Scotland's energy supply, help tackle climate change and create 600 jobs during construction and a further 180 permanent posts once in operation.
Chief executive Charles Hammond said: "Scotland has the potential to be a real powerhouse in renewables.
"These modern plants will provide clean, renewable energy and will make a major contribution to meeting Scotland's energy needs in the decades ahead."
Ian Marchant, chief executive of SSE, added: "Creating Forth Energy was designed to give us a new series of opportunities to pursue sustainable energy developments, and these proposals come in to that category.
"It is clear biomass will play an increasingly important role in energy production over the next 10 years and it is an area in which SSE expects to be a significant player."
The firms said they would submit planning applications for the plants next year.