According to Reuters, the money that comes from CO2 permits are invested in climate solutions that compensate for the emissions released.

Some traders say that lower wind speed and a reduction in solar power meant that it was necessary to produce power using fossil-energy, which led speculators to increase the price of permits.

The temporary return of coal as an important energy source also made it so that more CO2 permits were necessary, but coal-fired plants will eventually be replaced with renewable solutions, experts say.

Poland officials urged EU representatives to limit permit price hikes, as the country makes use of coal for a lot of its energy demand.

Other EU countries that aren't relying as much on fossil power said that increasing prices of carbon permits are necessary in order to encourage a fast transition to renewables.

Mark Lewis, head of climate research at Andurand Capital Management, said that renewable green hydrogen generation might become competitive, should the prices of carbon stay above 100 euros per ton.