Transmission and interregional trade can lead to leakage.

Under State Action, the North Central region imports fossil-based electricity from the unconstrained Central region.

But under State Action, California increases electricity imports from the Southwest and spurs out-of-region renewables.

State-led action = more electrification.

Under State Action, we see more EVs, heat pumps, and electrified industry in participating states, requiring +900 TWh/year over National Action. But non-participating states retain a fair amount of natural gas and coal generation without a federal cap.

We modeled two scenarios using Temoa:
• State Action: net-zero by 2050 in 23 politically-willing states
• National Action: same CO₂-eq reduction but achieved with a nationwide cap

Both reduce emissions 46% by 2050, but with very different tech pathways.

Electrification (think heat pumps and EVs) decisions were optimized within the model and varied based on carbon cost. At $400/t—sufficient to achieve net-zero emissions by 2050—U.S. electricity generation more than doubles compared to today to most cost-effectively reduce emissions.

Our marginal abatement cost curves reinforce this message.

Emissions abatement is increasingly costly as the energy system decarbonizes.

But, as technologies improve, there is greater opportunity for cost reductions in future years, resulting in more emissions reductions at comparable costs.

Here are CO2eq emissions under discrete carbon costs.

$40/t cuts emissions 36% with more wind and solar, and some electrified space heating and transportation.

$100/t gets a 63% drop, near elimination of coal, substantial reductions in the industrial sector, and more widespread electrification.

We found the greatest range of outcomes related to carbon management. For example, in some cases, direct air capture was scarcely used before 2050, while in other cases it provided substantial share of the CO2 mitigation.

Because we endogenize end-use technology selection, we are able to explore the range of future electricity demand and rates of electrification. In all near-cost-optimal cases, we see substantial expansion of the power sector.

Natural gas use in 2050, though, could vary anywhere from near zero use to current levels of consumption, with most of the range occurring in the industrial sector and the potential use in direct air capture.

We see some commonalities across the 1,100 near-cost-optimal net-zero futures. No surprises: we’re going to need to build a lot of solar and wind, and burn very little coal and oil.

I bet you are, Eversource.

Panel alert! I’ll be moderating a session on “Communicating uncertainty in macro energy systems to decision-makers” with Clean Air Task Force’s Leslie Abrahams, EIA’s Joe DeCarolis, and EPRI’s Naga Srujana Goteti. Wednesday, Feb 7 at 12:00pm ET.

Register at: stanford.zoom.us/webinar/regi...