The paper presents the impact of the reformed EU ETS (Emission Trading Scheme – ETS in the European Union) on the currently operating market for trading in CO₂ emission allowances. The new Directive introduced a number of changes aimed at tightening the climate policy, which the Polish energy sector based mainly on hard coal may mean an increase in the costs of electricity production, and thus an increase in the cost of the entire economy. The main goal of the changes is to achieve one of the objectives the European Union has set for itself, i.e. the reduction of CO₂ emissions by 40% until the year 2030. These assumptions are the result of joint arrangements of the EU countries under the Paris Agreement on climate change adopted in 2015. The Directive introduces a new market stability reserve mechanism (MSR) which, according to its assumptions, is designed to ensure a demand and supply balance of the ETS. Bearing the balance in mind, it means the reduction of excess allowances, which, although their number is decreasing, it is decreasing to slowly according to EU legislators, still oscillating around 2 billion EUA. The paper also draws attention to the rigorous assumptions adopted in the new Directive, aimed at increasing the price of CO₂, that is the costs in electricity production. Due to manually-controlled prices, are we doomed to high CO₂ prices and therefore the prices of electricity? What are its estimated maximum levels? Will the new assumptions encourage the Member States to switch to lowcarbon technologies? Can they weaken the economies of countries that are currently based mainly on coal energy sources, and strengthen countries where green energy is developed?