The Energy Saving Trust's Plugged-in Fleets initiative, run with EDF Energy, offers free guidance on how electric vehicles can add value. London has around 1,300 charging points.
As part of the project, the use of trucks by Urban Planters, councils and companies such as Morrisons is being analysed to pinpoint where electric vehicles could provide an alternative.
Energy Saving Trust manager Caroline Watson said: "We have shown that organisations can save money by selectively introducing electric vehicles to their fleets. Our advice team can provide impartial recommendations."
Transport minister Norman Baker said: "Electric vehicles are an essential part of the low-carbon revolution. This scheme will give fleet managers the information they need to pick the right vehicle for their business."