A wholesale removal of oil-and-gas drilling bans that cover many public lands and waters would raise only limited federal revenues over the next decade, according to a new Congressional Budget Office study that could provide political ammunition to drilling foes.

The nonpartisan budget analysts, in a report requested by the House Budget Committee Chairman, examined the effects of allowing drilling in Alaska’s Arctic National Wildlife Refuge (ANWR), and removing restrictions that also cover other lands and offshore areas.

Royalty and leasing revenues are a big source of non-tax federal cash, and CBO estimates that under current policies, proceeds from federal leases will total about $150 billion over the next decade.

But opening new areas won’t add much to that tally any time soon, given the lag time between lease sales and when oil and natural gas actually start flowing from these regions.