Natural Gas Stocks Inventory in Portugal increased to 3.11 TWh on Sunday March 29 from 3.10 in the previous day. Natural Gas Stocks Inventory in Portugal averaged 2.39 TWh from 2011 until 2026, reaching an all time high of 3.92 TWh in August of 2020 and a record low of 0.00 TWh in January of 2011.