A subtle but important difference between voluntary offsets and compliance carbon credits: Voluntary offsets are based on the concept of additional emissions reductions or removals. To be a valid offset, the project must've not been possible without funding from the offsets, and the amount of offsets issued must be additional to a business-as-usual baseline. Compliance credits are based on actual emissions versus either an absolute amount cap or an amount calculated from output multiplied by the carbon intensity of production. You pay if you're above your cap. It's that simple (well, no, nothing with a government regulator is ever simple, but ...) As a result, for example, renewable energy projects may not qualify as valid voluntary carbon offsets because the low cost of wind and solar have made them the most economical choice, but they would qualify for compliance credits if they lower your regulatory emissions account.