Despite the relevant role of green hydrogen in the pathway to net zero, its market is still developing, mainly due to its high production cost compared with gray hydrogen. An optimal portfolio selection, considering the grid as a backup, is needed to achieve a cheaper and more stable electricity supply and, thus, reduce costs in the short term. Other aspects can help reduce costs, such as demand flexibility, reduction of perceived risks, and the implementation of hydrogen storage. An optimization model was developed and implemented in Julia programming language to test and analyze the impact of these aspects on hydrogen production costs and project design. Using the model, it was possible to conclude that the usage of the grid as a backup has the most relevant impact on the levelised cost of hydrogen (LCOH), reducing it from 6.4 USD/kg in the reference case to 4 USD/kg. However, the possibility of using the grid while still complying with the European regulation for RFNBO will be at risk if the share of electricity produced using fossil fuel increases in the Brazilian power matrix. Without the possibility of using the grid, Brazilian hydrogen projects will need to adopt other flexibility and risk aversion methods to reduce the LCOH and still maintain a possible position in the international hydrogen market.