Piebalgs writes on his Web site that the European Union encourages local environmental initiatives though the Covenant of Mayors.
The Covenant of Mayors is a commitment by local governments to reduce greenhouse gas emissions and advance green energy technology beyond the energy guidelines for the European Union.
Local governments participating in the Covenant of Mayors receive technical and promotional support from the European Commission.
Piebalgs lauds a commitment by the municipalities in Barcelona province in Spain to cut emissions by more than 1 million tons by 2020. This, the commissioner notes, is about 20 percent of their current emissions.
"These first action plans show the time has now come to move from good intentions to concrete activities," he writes.
Piebalgs notes that 80 percent of the energy consumed in the region comes from major population centers.
"If we manage to cut emissions substantially (in cities), we will have gone a long way to reaching our ambitious climate objectives," he says.