The Energy Department set new efficiency standards Friday for big equipment, such as commercial boilers and portable air conditioners, after trying to block them for nearly three years.

The energy standards, finalized under the Obama administration in December 2016, will save consumers and businesses about $8.4 billion and cut carbon dioxide emissions by nearly 100 million tons over 30 years, according to the Energy Department’s own estimates. That is the equivalent of taking 21 million cars off the road for a year.

But the Trump administration had opposed the energy efficiency standards and only published them in the Federal Register now to comply with a unanimous ruling last October by the U.S. Court of Appeals for the 9th Circuit.

The publication “of these overdue standards is an important victory,” said Lauren Urbanek, a senior energy policy expert at the Natural Resources Defense Council. “It’s a heartening development in a period filled with strong advocacy for energy efficiency in the face of an administration senselessly devoted to moving backwards.”

The Energy Department has been responsible for establishing energy efficiency standards for household appliances and industrial equipment since 1987.

On Friday, the department published efficiency standards for commercial boilers for multistory buildings; uninterruptible power supplies such as the battery backup systems used to keep electronic devices running when the power goes out; air compressors used in equipment such as industrial paint sprayers or the machines that pump air into car tires; and portable air conditioners.

When the Trump administration blocked this group of standards, the NRDC, four other environmental groups, 12 states and two cities sued.

“There certainly wasn’t any technical reason to hold these up,” Urbanek said. “They had gone through the stakeholder process, they had gotten public comments. From our perspective the only thing we could see holding these up was the ideological reaction to regulation even when it’s common sense regulation.”

The litigation focused largely on the meaning of the word “will,” which the Energy Department said meant “may” and left the agency discretion not to publish the standards.

But the appeals court said “the word ‘will’ like the word ‘shall,’ is a mandatory term.”

It said “the rule’s use of the word ‘will’ unambiguously imposes a mandatory duty that constrains whatever discretion the Secretary might otherwise have possessed.”

The court cited a rule regarding the correction of errors in energy conservation standards and said that the rule “imposed upon the DOE a non-discretionary duty to publish the standards in the Federal Register, and its refusal to do so violated the rule.”

The Trump administration has sought to block new energy efficiency standards for a wide array of products. The Appliance Standard Awareness Project said that as of November 2019 the Energy Department had missed legal deadlines for 19 products, and more are due this month.

Urbanek said that “DOE is also moving in entirely the wrong direction” with these other appliances, notably the recent issuing of a rule to allow sales of inefficient incandescent and halogen lightbulbs. Stricter standards were to go into effect Jan. 1.