US greenhouse gas (GHG) emissions last year rose 6.2% relative to 2020 as a jump in coal-fired generation and road transportation outpaced growth in renewables that supplied 20% of the country’s electricity for the first time, according to a preliminary analysis from research house the Rhodium Group.

The increase in transportation emissions – 31% of the US total – reflected high demand for motor freight services for consumer products and a modest recovery of passenger travel, it said in its report Preliminary GHG Emissions Estimates for 2021.

Power sector emissions – 28% of the US total - increased 6% in 2021 as utilities used more coal in response to natural gas prices which doubled during the year, the first annual increase in coal-fired generation since 2014.

As a result, gas slid to 37% of overall generation from 40% in 2020, while coal rose to 23% from 20%. Renewables provided 20%, up from 19%, while nuclear declined to 20% from 21%, according to the report.

Both sectors last year claimed back about two-thirds of the decline from 2019 levels. Industry, which generates about 25% of emissions, made up just over half the difference from 2019 levels.

“The uptick in GHG emissions move the country even further from meeting its Paris Agreement climate target of reducing emissions 50-52% below 2005 levels by 2030,” said the report authors.

In 2020, emissions in the US fell to 22.2% below 2005 levels, but “ticked up to 17.4%” last year. The research group had anticipated higher emissions after they plunged more than 10% in 2020 during the initial Covid-19 outbreak, a record one-year decline.

The US economic recovery has been uneven due to the emergence of new coronavirus variants, availability of vaccines, and ongoing prevention measures and this has kept total emissions below pre-pandemic levels, they wrote.

Nevertheless, the report highlights GHG emissions appeared to have rebounded faster last year than growth in the $22trn national economy.

President Joe Biden’s strategy to accelerate the US transition from fossil fuels to meet the Paris target and regain global leadership on climate change suffered a setback last month when the $2trn Build Back Better legislation failed to advance in the Senate. It contained about $555bn in clean energy funding including tax credits for electric transmission, energy storage, solar, and wind.

The White House appears ready to support a scaled-down version of the bill but details and a potential legislative path forward are unclear.