New presidential administrations are not prone to praising or, for that matter, keeping the policies of their predecessors, especially when they have been bitter rivals.

On the subject of energy efficiency, the Trump administration may want to resist the temptation for a re-start, by considering the potential for huge savings from the actions of the Obama administration.

According to the American Council for an Energy Efficient Economy (ACEEE), several steps taken in the last eight years could save the country billions, and even trillions of dollars.

The ACEEE looked at three policy areas in particular. Specifically, the study examined the effect of new vehicle emission standards implemented for cars and light trucks, updated appliance standards, and the regulations of carbon emissions from non-vehicular sources through such policies as the Clean Power Plan, which applied to power plants.

Controversies surrounding some of these actions notwithstanding, the ACEEE looked at the results and found that these three policies combined are helping Americans save about 2 quadrillion Btu (quads) of energy this year, or about 2 percent of all U.S. energy use. These energy savings are worth about $30 billion this year.

While these initial savings are incredible, the long-term benefit should be even better, according to the ACEEE. The report asserts that the real benefits should arrive long after Obama and even after Trump leaves the Oval Office.

As these policies are allowed to have an imprint on product choices and consumer behavior, the savings will really take off. By 2030, the report projects savings of 10–14 quads of energy a year (10–14 percent of all energy use), worth $250–290 billion a year. By 2040, the savings continue to increase to 13–17 quads and $370–410 billion a year.