All materials suffer from breakdown when a strong electric field is applied to them. Breakdown implies the flow of current through a material, which results in high temperatures generated due to Joule heating effect. This process can be utilized as a way to induce thermo-chemical decomposition of biomass and some byproducts of gasification, such as biochar. By approximating biochar using the properties of graphite, a semiconductor model used in the literature to analyze Joule heating of graphene transistors, is modified and adapted to study charge and heat transport in graphite due to the application of voltage. Temperature distributions inside the material, electron and hole densities, and Joule heating values are reported based on one-dimensional simulations.