Objectives: Energy transition scenarios are prospective outlooks describing combinations of changes in socio-economic systems that are compatible with climate targets. These changes could have important health co-benefits. We aimed to quantify the health benefits of physical activity caused by active transportation on all-cause mortality in the French negaWatt scenario over the 2021–2050 period.Methods; Relying on a health impact assessment framework, we quantified the health benefits of increased walking, cycling and E-biking projected in the negaWatt scenario. The negaWatt scenario assumes increases of walking and cycling volumes of +11% and +612%, respectively, over the study period.Results: As compared to a scenario with no increase in volume of active travel, we quantified that the negaWatt scenario would prevent 9,797 annual premature deaths in 2045 and translate into a 3-month increase in life expectancy in the general population. These health gains would generate €34 billion of economic benefits from 2045 onwards.Conclusion: Increased physical activity implied in the negaWatt transition scenario would generate substantial public health benefits, which are comparable to the gain expected by large scale health prevention interventions.

Background Energy transition scenarios are prospective outlooks describing combinations of changes in socio-economic systems that are compatible with climate targets. These changes could have important short-term health co-benefits. We aimed to quantify the health benefits of physical activity caused by active transportation on all-cause mortality in the French negaWatt energy transition scenario over the 2021-2050 period. Methods We conducted a heath impact assessment of increased walking, cycling and E-biking projected in the negaWatt scenario. Time-varying mileage of walking and cycling projected by the scenario were distributed across the French population according to various hypotheses up to 2050. We quantified the number of premature death and years of life lost (YLL) prevented by increased physical activity. Health benefits were monetised based on the value of statistical year of life. Results The negaWatt scenario assumes increases of walking and cycling volumes of +11% and +612%, respectively, over the study period. As compared to a scenario with no volume increase, we quantified that the negaWatt scenario would prevent 9,797 annual premature deaths in 2045 and generate 34 billion euros of economic benefits from 2045 onwards; cumulatively over the study period, it would prevent 215,000 premature deaths and generate 696 billion euros of benefits. In 2045, health benefits would translate into a 3-month increase of life expectancy in the general population. Conclusions Increased physical activity implied in the negaWatt transition scenario would generate substantial public health benefits, which are comparable to the gain expected by large scale health prevention interventions.