The Top Five Portfolio Strategies
| Combination | Deaths Avoided | Cost | DAC Share |
|---|---|---|---|
| T2 + B2 (Accelerate Both) | 1,424 | $4.0B | 20.1% |
| T2 + B1 (Accelerate Transport Only) | 1,361 | $2.0B | 20.2% |
| T2 + B4 (Accelerate + Cooking First) | 1,366 | $2.5B | 20.2% |
| T2 + B3 (Accelerate + New Only) | 1,339 | $2.0B | 20.2% |
| T1 + B1 (Baseline Both) | 1,001 | $0 | 20.4% |
All results at 2035 horizon. 20 scenarios = 5 transport × 4 building. 10,000 MC draws per combination. Baseline deaths: 14,699/yr.
The Effects Simply Add Up
The structural question for combined policy analysis: do transport and building electrification interact, or are they independent? If they interact, optimizing each one separately gives the wrong answer for the joint problem.
The combined effect (1,424 deaths avoided) is within 1% of the sum of individual effects (1,313 + 118 = 1,431). The sectors are effectively independent in the source-receptor model. Transport emissions and building emissions come from different source categories with different spatial patterns, and the ISRM handles them linearly.
This simplifies the policy problem. CARB can optimize each sector on its own — T2 for transport, B1 for buildings — and sum the results: T2+B1 at $2B avoids 1,361 deaths.
Where the Marginal Dollar Goes
T2 alone: $2B buys 1,361 deaths avoided at $1.47M each. Adding B2 for another $2B buys only 63 more — $31.7M per death, nearly 3× the EPA VSL of $11.6M. The marginal return drops ~22×. Spend on transport acceleration, not building acceleration.
20 combined scenarios (5 transport × 4 building) · 10,000 Monte Carlo draws · 2035 horizon · Additivity validated: combined effect within 1% of sum of individual effects · ISRM linear source-receptor assumption confirmed empirically · EPA VSL $11.6M (2024$)