In one of its final votes of the session, the state Senate passed a controversial bill this morning that would force state utilities to purchase synthetic natural gas from a plant proposed for downstate Illinois.

The bill paves the way for Power Holdings of Illinois LLC’s to produce gas from Illinois coal in Jefferson County by guaranteeing that the plant would have a market for the gas it produces for the next 10 years: Illinois consumers.

The vote follows a similar bill that passed last week that forces utilities to purchase the total output of a coal-to-gas plant proposed for Southeast Chicago by Leucadia National Corp. for the next 30 years.

Together – if the governor signs the bills into law – it would mean that nearly a quarter of the gas used to heat Illinois homes for at least 10 years would come from the two proposed plants.

While the bills’ supporters say the agreements will mean jobs and a guaranteed market for Illinois coal, consumer advocates are outraged saying that Illinois consumers would pay a premium to purchase the synthetic version of something that is already cheap and abundant.

The Environmental Law and Policy Center, a Midwest environmental advocacy organization, estimates that the price for the synthetic gas could be double that of natural gas based on projections from the U.S. Energy Information Administration.

The governor has 60 days to sign the bills into law.