EU lawmakers could reach a compromise on the MSR over the treatment of unallocated allowances but not by bringing forward its start date from 2021, Polish climate negotiator Marcin Korolec said in an interview with Bloomberg news.

He said the EU Council representing the 28 member states would not budge from its position of a 2021 start date.

But he added it may be willing to agree to putting some of the unallocated phase 3 allowances directly into the MSR if this does not affect allowances awarded to member states and the transfer of backloaded allowances into the reserve is made voluntary for each country.

The EU Council and Parliament are in trilogue negotiations over the bill. Both the Council and Parliament have previously agreed that the 900 million backloaded allowances be placed directly into the reserve.

The two institutions are divided on the other two major price-impacting issues: Parliament wants the MSR to start by 2019 and for all the unallocated allowances to enter it, while the Council has a common position to start the MSR in 2021 and to postpone a decision on unallocated allowances.

The trilogue talks, which also involve the European Commission, are due to resume on May 5 and May 26.