The reduction in price of solar PV technology led, in the recent years, multiple investors to apply for installing new solar PV power plants in Portugal which would operate without subsidies or feed-in-tari s. In 2016 it was reported the approval of construction of such power plants and given the low variable cost of this technology it is expected that their penetration would reduce the electricity market prices. Hence, before doing the economic assessment of potential new solar PV power plants included in this regime it is important to quantify the impact that these units themselves would have on the market prices, and consequently on their revenues. This thesis aims to calculate this potential maximum impact of a given scenario of 480 MWp with every solar PV producer in it willing to produce at 0 e/MWh.