The council said it was replacing smaller vehicles at the end of use with electric versions and aimed to replace larger vehicles in future.
The new vehicles include 24 midi vans, which will be used across council services, and five vans being converted for use by neighbourhood wardens dealing with stray dogs.
The new vehicles add to the existing electric fleet, which includes a refuse collection vehicle, eight pool cars and two midi vans.
Cllr Mark Wilkes, Durham CC’s cabinet member for neighbourhoods and climate change, said: ‘Reducing carbon emissions within our own services is a key priority for us as we aim to tackle climate change as a county.
‘This scheme coincides with our aim to make electric charging more accessible across the county. We are currently in the process of installing 250 public EV charge points, so that residents have the option to travel more sustainably.’
This year, the council hosted the third Local Electric Vehicle Infrastructure roadshow, an event which supports local authorities in England in planning and delivering charge point infrastructure for residents without off-street parking.