The US Environmental Protection Agency (EPA) has confirmed its plans to restrict new greenhouse gas emissions rules to America’s largest power plants and industrial facilities, reiterating that it is committed to introducing the rules using a “common-sense, phased-in approach”.

The watchdog issued a statement yesterday confirming that following a consultation with state governments it would follow its original proposals that restrict new greenhouse gas permitting requirements to large facilities that emit more than 100,000 tons a year of carbon dioxide equivalent (CO2e).

The announcement comes after the Supreme Court last month threw out a legal challenge questioning the EPA’s right to place restrictions on greenhouse gas emissions under the Clean Air Act.

The decision allows the watchdog to proceed with a new regime of so-called Prevention of Significant Deterioration (PSD) permits, which require new facilities and those that make major modifications to existing facilities to implement energy-efficiency measures.

Under the rules confirmed yesterday, PSDs will be required for new facilities that emit more than 100,000 tons a year of CO2e and existing facilities that emit more than 100,000 tons a year of CO2e and make changes that increase annual emissions by 75,000 tons a year. Meanwhile, new and existing facilities emitting more than 100,000 tons a year will have to obtain separate operating permits.

The controversial rules have been welcomed by green groups and are widely seen as a first step towards using the Clean Air Act to further restrict greenhouse gas emissions from power plants and industrial facilities over time.

However, a number of industrial groups and Republican politicians have condemned the move as an additional cost for businesses that will drive up energy bills.

The EPA has repeatedly argued that any additional costs of compliance with the rules will be more than compensated by environmental and health savings, as well as energy-efficiency improvements at the facilities covered by the rules.

The watchdog also confirmed yesterday that it has finalised a new provision “that allows companies to set plant-wide emissions limits for GHGs, streamlining the permitting process, increasing flexibilities and reducing permitting burdens on state and local authorities and large industrial emitters”.