Topeka ? The Kansas Senate on Tuesday approved another bill that would require the construction of two 700-megawatt coal-burning power plants in southwest Kansas.

The 24-10 vote and expected approval in the House later Tuesday night will probably set up another showdown with Gov. Kathleen Sebelius over the issue that has dominated the 2008 legislative session.

Sebelius has already vetoed two bills authorizing the plants, citing concerns about the environmental effects of the project’s carbon dioxide emissions.

In order to try to gain more support in a possible veto override vote, plant supporters married the project to several other economic development initiatives in one piece of legislation.

Several senators said that violated the Kansas Constitution prohibition against having more than one subject matter in a single bill.

“This clearly contains multiple unrelated subjects and therefore is unconstitutional,” said Senate Democratic Leader Anthony Hensley of Topeka.

But Sen. Nick Jordan, R-Shawnee, said all the provisions of the bill fall under the heading of economic development.

State Sen. Marci Francisco, D-Lawrence, voted against the measure, and state Sen. Roger Pine, R-Lawrence, voted for it.

Movement of another coal bill also indicated that the Legislature was marching toward the end of the wrap-up session. Lawmakers will return May 29 for the official last day of the session and possibly another attempt to override Sebelius’ veto, which takes a two-thirds majority of both houses.