By Taylor W. Anderson, The Bulletin.

PORTLAND — Before starting to implement Oregon’s low-carbon fuel standard , the state must first deal with some math that is both complicated and controversial.

To make sure the program actually cuts as many emissions as purported under the complex renewable fuel policy, the Oregon Department of Environmental Quality is considering adopting models that account for the greenhouse gases indirectly emitted by renewable fuels when land is used to produce biofuels instead of food. The concept is known as indirect land use change, or ILUC.

That type of accounting is a new and disputed science between climate experts and the companies that must comply with the low-carbon fuel program. It is maligned by some biofuels companies and revered by climate scientists who say it’s the only way to potentially cut emissions through the low-carbon fuel standard.