Price collars have frequently been advocated to restrict the price of emissions permits. Consequently, collars were incorporated in the three bills languishing in Congress as well as in California?'s AB-32; Europeans are now considering price collars for EU ETS. In advocating collars, most...

Previous analyses of cap-and-trade programs regulating carbon emissions assumed that firms must surrender permits as they pollute. If so, then the price of permits may remain constant over measurable intervals if the government injects additional permits at a ceiling price or may even collapse...

Virtually every analysis of cap-and-trade programs assumes that firms must surrender permits as they pollute. However, no program, existing or proposed, requires such continual compliance. Some (e.g. the Acid Rain Program limiting SO2 emissions) require compliance once a year; others (e.g. the...