A CREB is a special type of tax credit bond providing rural electric cooperatives, municipal electric utilities, and government entities (including tribal councils) the equivalent of an interest-free loan for financing qualified energy projects. CREBs were created in the Energy Policy Act of 2005, and are largely modeled on the Qualified Zone Academy Bond program that provides tax credit bonds for school renovation and upgrades in certain qualified school districts. They deliver an incentive comparable to the production tax credit that is available to private renewable energy project developers and investor-owned utilities. $800 million of CREBs were allocated by the U.S. Treasury for 2006 and 2007 through an application process by qualified borrowers. The program was fully subscribed for 2008 for $400 million of bonds.