This thesis employs simulation and optimization to conduct a multi-scale investigation of the cost and performance of two hydrogen transition pathways. Chapter 2 simulates production pathways for green hydrogen in Canada's Atlantic Maritimes. Projects could be implemented by 2050 and at <2 $/kgH2 with aggressive growth rates, learning rates, and electrolyzer capital costs of 500 $/kW. Chapter 3 develops a method to estimate the thermal loads in remote and northern communities. It applies this method to 40 communities and develops a regression model that estimates thermal loads. Chapter 4 builds an optimization model that deploys wind turbines and reversible fuel cells to meet the electrical and thermal loads of those 40 communities. This model overbuilds wind capacity. Five communities have costs of avoided emissions of <200 CAD/tCO2, while 30 have costs of <500 CAD/tCO2.