In the context of the depletion of fossil fuels and the rising climate change impact, Cuba is a small island country with a lack of conventional energetic resources and, in addition, has limited access to the energetic resources market due to the restrictions imposed by EE.UU blockade, therefore the only way to reach energetic independence is to increase the share of renewable energy sources in the energetic mix. The rising of generation of electricity with renewable energy sources like solar and wind has the problem of the intermittence of these resources and contributes to worsening the flexibility of the power system. This work presents a preliminary evaluation of the flexibility of the Cuban Power System toward the 2030 goal to reach 37% of renewable energy share in electricity generation using a modified USAID-NREL analytical framework for the flexibility analysis, with five indicators that average form a power system flexibility score. This methodology permitted an assessment of Cuban power system flexibility from 2019 to 2030 and identified the indicators that Cuban Electric Union has focused upon and indicators that it is need to address for a more flexible power system and is a decision-making tool for the preparation for a new scenery with a high share of intermittent renewable energy.