TGE_MA - arithmetic mean of the clearing rates of the monthly GAS_BASE_M natural gas contract, listed on the commodity futures market of the Towarowa Giełda Energii, with delivery in the calendar month for which the price is determined from the formula. The average is calculated for the quotations available in the period: from the last calendar day in a month distant from the delivery month by 2 months and on each day of the calendar month preceding the delivery month, expressed in PLN / MWh. Daily clearing prices are published on the website of Towarowa Giełda Energii (www.tge.pl)