Renewable forms of energy are increasingly penetrating the electricity market, particularly, geothermal energy. A wide range of resource temperatures and fluid quality are converted mostly using traditional binary power plants and, recently, using Climeon modular units. Portuguese natural geothermal resources are far from precise estimations. Despite the parameter uncertainties, electric power resource estimations of two natural geothermal reservoirs are presented: a volcanic sourced heated high-enthalpy geothermal reservoir in Sete Cidades, São Miguel Island, Azores; and a low-enthalpy geothermal reservoir linked to a fractured zone in a granitic setting in Longroiva, in the northern part of the Portuguese mainland. Based on the volumetric method, we assessed the power potential of geothermal resources in Sete Cidades and Longroiva using a probabilistic methodology-Monte Carlo simulation. The average reserve estimations for Climeon module were 5.66 MWe and 0.64 MWe for Sete Cidades and Longroiva, respectively. This figure was by far higher when compared to traditional binary technology; those differences were mostly attributed to distinct conversions efficiency factors.Commercial competitive transformation of geothermal heat (i.e., water or steam) into electricity requires a design with good efficiency. Geothermal traditional binary power plants require a geothermal fluid operational minimum inlet temperature higher than 90 • C (with some special exceptions, such as the Chena Hot Springs geothermal power plant in Alaska, with an inlet temperature of 73.9 • C and an outlet of 10.0 • C). Lower inlet fluid temperatures of traditional binary power plants imply low to very low energy conversion efficiency, turning these power plants without commercial feasibility [5]. However, recently, new modular and easy to install small-size compact Climeon heat power converters (SCHPCs) have come on the market, mostly resulting in increased conversion efficiency [6,7]. With medium/low enthalpy inlet water or gas temperature in the range 70 • C to 120 • C, the technology enables excellent efficiency in the range of 10-14% under good conditions, with high inlet temperature and flow combined with a cooling source providing low temperature and good flow. Reasonable efficiency in the range of 5-10% can be obtained even at less favorable conditions, depending mostly on inlet temperature and flow and cooling source temperature and flow. The Climeon technology can be useful in a wide range of use cases, from the early stages to the very end of a geothermal reservoir's exploitation, independent of the size and nature (natural or engineered) of the reservoir.For large geothermal projects, before the adequate characterization of a reservoir's extractable reserves (enthalpy, fluid quality, and available mass flow), when beginning geothermal exploration, well tests, and designing and fabricating the power plant, the Climeon modules can be quickly installed and powered into the market, thus allowing the owner to potentially generate a profit ...