With the VAPEX process, combinations of vaporized solvents are injected into heavy oil and bitumen reservoirs for in situ recovery of the oil. The oil is diluted with the solvent, which reduced the viscosity so the oil drains by gravity to a horizontal production well. The VAPEX process has the potential to greatly reduce the greenhouse gas emissions for oil sands and heavy oil recovery since it is a non-thermal process that does not require the reservoir to be heated with, for example, steam. The Petroleum Recovery Institute (PRI) was the operator of a joint industry project of 16 participants with nine research performing organizations. During 1998, the project investigated the full project engineering and commercial scale economics for the VAPEX process. The supply cost economics for VAPEX oil production from the Athabasca oil sands, Cold Lake oil sands and Southeast Alberta heavy oil were determined. The work indicated that VAPEX has attractive economics and helped to define the critical field operations design issues that need to be addressed prior to proceeding with a substantial field pilot. The climate change advantages of the VAPEX process are described in the paper along with an overview of the integrated physical model, numerical simulation, facilities design, well specifications, production, transportation, and marketing work which led to calculation of the supply cost economics.