The Congressional Research Service is basically the federal government's think tank.

As a legislative branch agency within the Library of Congress, the service writes reports on the effects of different bills for members of Congress, their committees and staff.

In a March 8, 2006, report on the Energy Policy Act of 2005, the research service concluded that the bill would actually lead to a tax increase for oil companies:

The $2.9 billion in energy tax increases, which increase the tax burden of U.S. refineries, offsets the $2.6 billion in tax cuts for the oil and gas industry as a whole. In fact, focusing only on refineries, their $2.9 billion in tax increases far outweigh the $400 million of tax cuts provided by the act (over 11 years).

A recent TV ad by Majority Action criticized U.S. Sen. Elizabeth Dole for voting for the act.

It is not clear whether the report includes the royalty relief in its calculations.