CO HB1240

Conditions the Colorado Public Utilities Commission's consideration of federal carbon tax costs on the actual adoption of a carbon tax as part of federal law, rather than merely the likelihood of such regulation.

Requires the PUC to consider costs "imposed by current federal law or regulations" on greenhouse gas emissions when evaluating utility proposals to acquire resources.

Limits the rate of return that utilities may earn on new generation facilities that replace existing generation facilities not yet fully depreciated to one-half the rate of return permitted on existing generation facilities.

Takes effect 90 days after the 2011 legislative session ends (August 10, 2011), unless subject to a referendum petition, in which case implementation requires voter approval at the November 2012 general election.