A few years ago, Mace et al. developed an algorithm to calculate self-diffusion coefficients from the potential energy surface of an adsorbate molecule, based on the transition state theory. In their work, they used a clustering algorithm to identify the adsorption sites, transition states, and connecting tunnels within the material for a specific adsorbate, which are then leveraged to run a lattice kinetic Monte Carlo simulation from which the mean square displacements are deduced. We were inspired by this approach, but are more interested in the present work in the use of the energy barrier itself: instead of using it to determine transition probabilities, we have developed a simplified version of the algorithm that only focuses on the energy at which the diffusion tunnels have percolated (i.e., become all connected).