Canadian policy makers and energy scholars acknowledge that significantly reducing GHG emissions from Canada’s electricity system is a crucial step toward achieving “net-zero” emissions by 2050 (Government of Canada 2020; Dion et al. 2021). Canada is a leader globally in low-emissions intensity electricity generation (Shaffer 2021, 2) but this standing masks broad disparities between provinces reliant on large-scale non-emitting hydro power such as Manitoba and British Columbia and fossil-fuel dependent provinces such as Alberta, Saskatchewan, Nova Scotia and New Brunswick (Macdonald 2020; Shaffer 2021; Hoicka and MacArthur 2018). Within this context, the province of New Brunswick presents a curious puzzle: in 2019-2020, 80.4% of its electricity generation was from non-emitting sources, a dramatic change from 40% non-emitting in 2010. How did one of Canada’s four “fossil fuel-based provinces” (Shaffer 2021) achieve this decarbonization? This study finds NB’s initial decarbonization was spurred by a combination of nuclear refurbishment, coal phase-outs, increased interprovincial energy transmission, and small-scale community energy projects, all of which were framed by policy makers, utility officials, and regulators as providing economic benefits to the province. However, we find that the very factors that have contributed to improvements in New Brunswick’s energy system are likely to hinder further decarbonization. The province has been unwilling to scale up in-province renewable energy generation, has sought to delay further coal phase-outs, and has been unable to secure increased high transmission agreements with Quebec. We argue that New Brunswick’s current state reflects the pernicious challenge of a “double-carbon trap” in which jurisdictions manage to improve their emissions pathways over a basic threshold but which stall or plateau prior to achieving deep decarbonization (Bernstein and Hoffmann 2019; Seto et al. 2016). The paper concludes with a discussion of the ways in which changes to the framing of the issue and increasing the capacity of regulators could help the province get “unstuck” on its path toward deep decarbonization.