WASHINGTON (AP) _ President Bush, in his much-awaited energy plan, will warn on Thursday that the United States faces ``the most serious energy shortage since the oil embargo of the 1970s.'' He will order federal agencies to dismantle regulatory barriers that slow gas, electrical, coal and nuclear power production and propose opening federal lands for oil drilling.

He also will encourage conservation, setting aside most of the $5 billion in new tax incentives for people who buy energy-efficient cars or use alternative energies. The 163-page policy, developed by a task force headed by Vice President Dick Cheney, also orders review of fuel economy standards with an eye toward raising the minimum mileage requirement.

``A fundamental imbalance between supply and demand defines our nation's energy crisis,'' says the report, a portion of which was released Wednesday night by the White House. ``This imbalance, if allowed to continue, will inevitably undermine our economy, our standard of living, and our national security.''

The White House was releasing the report Thursday in connection with Bush's speech on the topic in St. Paul, Minn.