The company plans to construct a combined-cycle natural gas plant in Citrus County and two simple-cycle combustion turbine generators at the Suwannee plant near Live Oak, if plans are approved by the Florida Public Service Commission.

Additionally, it hopes to install new equipment at the Hines energy complex near Bartow to increase efficiency and power output.

Officials also announced the retirement timeline for two coal-fired units at the Crystal River energy complex.

If approved, the projects will benefit customers by increasing reliability and efficiency while reducing emissions.

"We are making these investments to continue providing our customers with the most cost-effective energy solutions and highest level of reliability with limited environmental impact," Duke Energy Florida president Alex Glenn said.

"We are committed to ensuring our customers' energy needs are met 24 hours a day, seven days a week, now and in the future."

Duke Energy Florida has selected its self-build option to construct a 1640 megawatt combined-cycle natural gas plant to help serve Florida's approximately 1.7 million customers starting in 2018.

The expected cost to build is approximately $1.5 billion ($A1.59 billion), including financing costs.

The plant will be located on 400 acres, neighbouring the Crystal River energy complex.

Construction and related activities are expected to add several million dollars to the local tax base.

Construction is expected to create 600-700 jobs.

If all regulatory approvals are received, construction is expected to start in early 2016.

The plant's first 820MW are expected to come online in spring 2018 and the second 820MW are expected to be available by December 2018.