To meet New Zealand’s emission commitments, the government has prioritized the up-take of Electric Vehicles (EVs), as personal transportation is a large consumer of fossil fuels. Extrapolating figures from official sources (Ministry of Transport and Ministry of Business, Innovation & Employment) we estimate that passenger transportation is responsible for at least 30% of New Zealand’s fossil fuel consumption. Given New Zealand has a large share of renewable sources (78%) the simple conclusion is that the uptake of EVs would directly reduce carbon emissions, however the interaction of EVs with the power system is complex and requires a comprehensive approach. Transition Engineering (TE) is an emerging field that addresses sustainability in design and management of engineered systems. Within the context of the TE methodology we investigated the implication of EV targets on the New Zealand Energy System and associated Greenhouse Gas Emissions. We utilized a Retro Analysis approach, using the transport activity and grid composition of 2012, superimposing various policy objectives into that system to understand the costs, benefits, consequences and utility of the policy. An energy system model was developed using the Longrange Energy Alternatives Planning System (LEAP). The model incorporated seasonal availability of power plants along with sector specific energy consumption profiles reported in official datasets. We defined a set of scenarios to examine the impact of different EV targets, charging behavior, modal shift, transport behavior and changes to grid composition. The implications of the intermittent nature of renewable resources were explored along with potential demand additions (EV charging) on the power system.