New EU Emissions Trading System: what should change?

Set up in 2005, the EU Emissions Trading System (ETS) is the world's first international emissions trading system. Since its establishment, the concept has had plenty of detractors. Now, with the UK set to leave the EU ETS and replace it with something else such as a carbon tax, and the incoming US administration of Joe Biden sounding unenthusiastic about cap-and-trade, EU policymakers are being prompted to think about other ways to price carbon. The European Commission is proposing to revise and possibly expand the scope of the ETS. They claim the ETS proves that putting a price on carbon is possible and makes economic sense, helping to move further towards a low carbon greener future.