The use of textile materials and structures to build textile-based TEGs is of particular interest as they can also offer unique textile properties. In this work, the initial goal is to present a prototype TEG measuring device and its experimental results for comparing the open circuit voltages coming from various pairs of knitted samples which may constitute part of a textile TEG. We focus on representing realistic testing conditions as on a wearable garment, by introducing a friction stage between the contact and separation stages which is applied under a lightweight load. Α second goal is to explore the possibilities of some environmentally friendly textile materials to provide electric energy, again under realistic conditions. From the carried tests, it was seen that even conventional natural knitted textiles structures like single jersey, without expensive and complex nano-treatments, can provide considerable voltages if they are part of a wearable garment. Moreover, it was found that even low friction under a weight load of 20grf is adequate to give the above results. The hereby presented measuring TEG device can be used in the comparison or improvement of textile or even non-textile based TEGs, in order to find optimal combinations of materials and designs to be used on clothing TEGs.