The optimal investment in power plants depends on many uncertain parameters (price of electricity, construction costs, cost of emissions, fuel cost...). Traditional approaches based on the Discounted Cash Flows methodologies, like the Net Present Value (NPV), do not properly take into account these uncertainties since they depend on the implicit assumption that all the decisions regarding the investment are evaluated in a specific moment (the time now) and cannot be postponed, waiting to acquire more information. An evolution of these methods is the Real Options Analysis (ROA) that considers a further value into the evaluation: the value of flexibility to choose when to invest. In this paper the ROA will be used to test a hypothesis made in literature, that small-medium sized plants (300-400 MWe) can be a suitable choice for small grids (or markets), thanks to their flexibility in the deployment. The assessment of this hypothesis is based on a ROA model that compares the investment in a Large Reactor (LR) vs. a group of Small Modular Reactors (SMR). Montecarlo simulations are used to approximate the probability distributions of the profitability indicators, both with a static approach, implying that investments are made immediately, and with a dynamic approach, letting the model decide when to invest (optimizing the profitability distribution). The result show as SMR, in small grid, can yield similar profitability in lower risky conditions.