Process heat electrification offers the prospect of deep decarbonization of the process industries. Replacing fossil fuel-fired boilers with electric ones can reduce carbon emissions if power is supplied from a grid with a high proportion of renewables. For multinational firms with plants in multiple locations, the electrification decisions should be scheduled based on grid carbon intensity projections and coordinated among these subsidiaries; in addition, carbon credits can be traded among the multiple sites to allow lagging plants to reduce their carbon footprints. Here we develop a novel mathematical model to optimize process heat electrification policies in multinational corporations. The model determines the optimal timing of electrification at each location, and also the necessary level of carbon trading within the multinational firm. An illustrative case study demonstrates how the proposed model can be used to generate electrification plans that are superior to those based on simple heuristics.