New options for the redesign of the eastern portion of Toronto's Gardiner Expressway could nearly double the cost of the project, if approved.

Three options were revealed in a new report from city staff, which will be brought before the Public Works and Infrastructure Committee next week.

The most expensive of the three options would add up to an additional $230 million to the project's approximate $260 million price tag.

Earlier this year, the city debated three options for what to do with the crumbling portion of the Gardiner Expressway east of Jarvis: maintaining it, removing it all together, or a "hybrid" option.

The "hybrid" option involves maintaining a link between the Gardiner and the Don Valley Parkway. The on- and off-ramps east of the Don River that extend to Logan Avenue will be demolished, and Lake Shore Boulevard will be widened to accommodate more traffic.

In June, Toronto City Council voted 24-21 for the hybrid choice. At the time, the net present value (NPV) cost estimate was $260 million in capital funding, and $76 million in "lifecycle" funding.

NPV is a calculation comparing the amount invested to the future value of the project. Taking away the NPV, the city estimated the entire project would cost $919 million in total.

The report to be considered next week outlines three "concepts" for consideration, and gives approximate NPV costs for each.

"All three design concepts would have minimal impact on private property and would facilitate development of the First Gulf site, as well as other developments proposed for the Keating, Port Lands and South of Eastern precincts," according to the report.

The first is similar to the city's initial plan, but would involve a new, realigned eastbound off-ramp connecting the Gardiner to Lake Shore Boulevard. It would run close to the Gardiner "without impacting adjacent development lands."

The report estimated that the capital cost would be approximately $260 million, the same as the estimate from June. It would include approximately 8.5 acres of new development.

Gardiner Expressway Concept 1

Concepts 2 and 3 would involve reconstructing the elevated eastern portion of the Gardiner between Cherry Street and the DVP, but would move the expressway further north.

The second concept would cost an additional $90 to $140 million NVP, and would include 12.5 acres of new development.

Gardiner Expressway Concept 2

The third concept is similar to the second, but would also include the widening of the Don Rail Bridge over the Don River. The Metrolinx bridge has space for additional roadway infrastructure underneath, but would have to be widened to accommodate vehicle traffic.

This option would cost an additional $120 to $180 million NVP, and would cover approximately 13.5 acres.

Gardiner Expressway Concept 3

On top of the initial costs, each project would require an additional $30 to $50 million in "public realm improvements," meaning the most expensive option (Concept 3) could run a bill of $230 million, plus the additional estimate of $260 million.

The report did not outline the full, uninflated costs, only listing the NPV costs. The full report is available online.

All three options will be subjected to an environmental assessment, to be completed and endorsed by council by early 2016.