The centres, at Stacey Avenue, Edmonton N18, Global Approach, Bow E3, and Delta Park, Smugglers Way, Wandsworth, will give fleets guidance on which are the cleanest vehicles and where to find them, how to convert vehicles already in service, approved converters and the availability of Autogas.
The sites are situated to allow access to fleets heading towards the congestion charging zone in London.
Calor's Lee Woodger said: 'It's another example of our commitment to support fleets in selecting the right fuel option. Now the congestion charge has bedded in, fleets can take a long, hard look. It's important they make the right choice.'