The adoption of domestic emissions trading schemes (ETS) can impose a heavy burden on energy-intensive industries. In particular, energy-intensive industries competing with foreign competitors could lose their international edge. Although the abatement of carbon dioxide (CO2) emissions in industrialized countries entails the reduction of their energy-intensive production, a corresponding increase in the production of energy-intensive goods in countries without CO2 regulations may lead to carbon “leakage.” This paper examines the effects of various allocation methods for granting emissions permits in the Japanese ETS on the economy and CO2 emissions using a multiregional and multisector computable general equilibrium model. Specifically, we apply the Fischer and Fox (2007) model to the Japanese economy to address carbon leakage and competitiveness issues. We compare auction schemes, grandfathering schemes, and output-based allocation (OBA) schemes. We further extend the model by examining a combination of auctions and OBA. Though the auction scheme is found to be the best in terms of macroeconomic impacts (welfare and GDP effects), the leakage rate is high and the harm to energy-intensive sectors can be significant. OBA causes less leakage and damage to energy-intensive sectors, but the macroeconomic impact is undesirable. Considering all three effects—leakage, competitiveness, and macroeconomics—we find that combinations of auctions and OBA (with gratis allocations solely to energy-intensive, trade-exposed sectors) are desirable.