The energy sector in the US is by far the largest source of greenhouse gas (GHG) emissions, responsible for more than 80% of total emissions excluding LULUCF. GHG emissions in the US increased significantly during the 1990s before levelling off and peaking in 2007. This trend was largely driven by changes in the energy sector, which was the fastest growing emissions source before peaking in 2005. Since then, energy sector emissions have declined by 15% (as of 2019), largely driven by the availability of cheaper fossil gas and renewables and the subsequent decline in coal consumption in the energy sector.
Within the energy sector, the highest share of emissions comes from the power sector (30%), closely followed by the transport sector (28%). Emissions from the industry and waste sectors have continued to decline since 1990 while agriculture emissions have increased slightly.
17 While global cost-effective pathways assessed by the IPCC Special Report 1.5°C provide useful guidance for an upper-limit of emissions trajectories for developed countries, they underestimate the feasible space for such countries to reach net zero earlier. The current generation of models tend to depend strongly on land-use sinks outside of currently developed countries and include fossil fuel use well beyond the time at which these could be phased out, compared to what is understood from bottom-up approaches. The scientific teams which provide these global pathways constantly improve the technologies represented in their models – and novel CDR technologies are now being included in new studies focused on deep mitigation scenarios meeting the Paris Agreement. A wide assessment database of these new scenarios is not yet available; thus, we rely on available scenarios which focus particularly on BECCS as a net-negative emission technology. Accordingly, we do not yet consider land-sector emissions (LULUCF) and other CDR approaches which developed countries will need to implement in order to counterbalance their remaining emissions and reach net zero GHG are not considered here due to data availability.
18 In some of the analysed pathways, the energy sector assumes already a certain amount of carbon dioxide removal technologies, in this case bioenergy carbon capture and storage (BECCS).
The United Statesʼ current GHG emissions
MtCO₂e/yr
Displayed values
By sector
Power
Transport
Industry (energy use)
Buildings
Fugitive emissions
Other
Agriculture
Industry (processes)
Waste
LULUCF
By gas
CO₂
CH₄
N₂O
Other
078%0
Sectors by gas
Energy
094%0
Agriculture
00
Industry (processes)
00
Energy system
The US primary energy mix is dominated by fossil fuels, with oil contributing 36% (mostly used in the transport sector), fossil gas 34%, and coal 12% in 2019. Nuclear energy accounts for 10%, while renewable energy makes up about 8% of the energy mix. The pace of renewable energy deployment in the US has lagged behind others such as the European Union, as retiring coal capacity has largely been replaced by fossil gas and regulatory rollbacks have supported fossil fuels.
The share of fossil gas in the power mix has been increasing, and it is largely replacing coal. In 2017, gas and coal had about equal shares in the power mix, but by 2019, the share of gas had increased to 38% while coal decreased to 25%. Nuclear (19%) and renewable energy including biomass (18%) made up the bulk of the remaining generation.
While there are existing policy gaps in the energy sector, President Biden has presented ambitious energy sector reforms including the goal to achieve a “100% clean energy economy” by 2050.8 Biden’s COVID-19 economic recovery plan also includes a target to achieve a “carbon-free power” sector by 2035.8 The Inflation Reduction Act, passed in 2022, is expected to help narrow this gap with significant measures targeting the energy sector such as support for renewable energy and electric vehicles.3
“At this time, the United States does not intend to use voluntary cooperation using cooperative approaches referred to in Article 6.2 or the mechanism referred to in Article 6.4 in order to achieve its target.”1
Long-term target
The US long term strategy (LTS) aims to reach net zero emissions by 2050.5 The LTS covers all greenhouse gases and sectors.