AGU Advances: Carbon‐Neutral Pathways
Updated: Mar 14
The team at EER published a new paper today in the journal AGU Advances titled "Carbon‐Neutral Pathways for the United States."
The work features the state-of-the-art in economy-wide, bottom-up, energy modeling with high temporal fidelity and encapsulates our learning from the several dozen decarbonization studies we have completed over the last five years. This work focuses on energy system dynamics, such as the interactions between electricity and fuels, using eight pathways that reach either net-zero or net negative emissions in 2050. Among the pathways is one that is compatible with a return to 350 ppm by 2100, a first within published research of this kind.
Several additional themes emerged from the work that are worth highlighting:
The cost of decarbonization has become dramatically cheaper over the last five years due to a combination of: (1) technology cost falling faster than expected; and (2) improved modeling tools aiding in the imagining of new infrastructure pathways. This conclusion comes from comparing our work in the U.S. Deep Decarbonization Pathways Project reports from 2014 where reducing emissions 80% by 2050 to 750 Mt was estimated to cost 1% of GDP. In this latest research, reducing emissions to -500 Mt in 2050 (compatible with a return to 350 ppm) is estimated to cost just over 0.5% of GDP. This is remarkable given that the 1.25 Gt in emissions reductions between 750 Mt and -500 Mt are also the most expensive to achieve.
Renewable electricity forms the foundation of the least-cost net-zero infrastructure transition. This result has been echoed by other work in the past. In this paper we highlight in new ways how reliability can be maintained in high renewable power systems at very low cost through the maintenance of existing thermal resources operating very few hours burning decarbonized fuel blends, including hydrogen, together with flexible industrial loads, such as electrolysis and dual-fuel electric boilers.
The actions required in the next 10 years are known with high confidence. Across a wide range of scenario input assumptions, the steps required to be on a path to net-zero are remarkably similar over the next decade, providing confidence for near-term legislative action. These actions include: a renewables build‐out (>500 GW total wind and solar capacity by 2030); coal retirement (<1% of total generation by 2030); maintaining current nuclear and natural gas capacity; and electrification of light‐duty vehicles (EVs > 50% of LDV sales by 2030) and buildings (heat pumps >50% of residential HVAC sales by 2030).
While this work shows that a transition to net-zero emissions in 2050 is both affordable and feasible, the success of this transition and benefits for society will depend on implementation details that still need further study. These include addressing many questions that involve allocation of cost and benefits, including: household cost burdens, changes in employment patterns, air quality impacts on local communities, and protection of domestic industries. Over the coming years, we will be turning our attention and modeling capabilities towards these new research topics addressing not just "what to do" but "how best to do it."
Artwork credit: Alisa Singer based on Sankey diagrams for the 100% Renewable and net-negative scenarios.