Addressing the climate crisis necessitates accelerating transitions towards climate-neutral systems of production and consumption, with electrification emerging as a crucial decarbonisation strategy. The acceleration of such net-zero transitions across multiple systems faces significant resistance and contestation. In this paper, we propose an extended list of challenges unique to the acceleration phase of socio-technical transitions: we introduce ‘expansion and contestation’, ‘justice’, and ‘international dynamics’ as additional challenge types to complement the already acknowledged challenge types of ‘whole system change’, ‘multi-system interaction’, ‘decline and resistance’, ‘consumers and social practices’, and ‘governance’. We apply this analytical framework to the electrification of private-passenger vehicles and investigate the unfolding transition to e-mobility with evidence from expert interviews in Germany and California. We uncover over 50 real-world challenges associated with these net-zero transitions at the beginning of the acceleration phase. Most challenges fall within the categories of ‘expansion and contestation’ and ‘governance’. While Germany and California share many real-world challenges, we also find significant variation between both jurisdictions, which we attribute to differences in their automotive incumbency, transition governance approaches, sectoral institutions and socio-political contexts. We discuss implications for future research, arguing for greater attention to the dual politics of acceleration during net-zero transitions: political conflict not only centres around the decline of old industries and future losses, but also around the expansion of the new system and associated future gains.