This chapter presents an overview of the demanding conditions of sliding bearing applications within hydropower plants, where the use of novel complex multiscale thermoplastic polymer composites is desired to combat the friction and wear issues. The three unique challenges of this application originate from its extreme contact pressure during operation (~  30 MPa), the longevity of operation (~  40 years) as the maintenance is significantly costly and complicated, and particularly the realization of oil-free or water lubrication from a sustainability perspective.

Green or sustainable tribology in hydropower applications is an emerging concept that emphasizes environmental adaptive lubrication (EAL) or fossil-fuel free lubrication with an improved or similar tribological performance. Polymers are the most promising materials for EAL lubrication compared to metal, as the corrosion becomes an important issue.

Recent investigations of several commercial and in-house made high-performance thermoplastic based multiscale polymer composite materials to solve the tribological issues in hydropower applications are presented in this chapter. Furthermore, various pre- and posttribological characterizations, detailed multiscale composite manufacturing processes, an important results are also described in detail.

To mitigate the effects of downstream lubricant spillage from hydroelectric power plants, environmentally friendly lubricants are required. For the sustainable operation of oil-free bearings, the development of high performance bearing materials is crucial. In this study, the tribological performance of PPS and UHMWPE-based composites, incorporating various reinforcements, such as graphene oxide, is evaluated and compared with five commercial materials. Experiments were performed under different lubricating conditions; Dry, water, and using a glycerol-based environmentally adaptive lubricant (EAL). The use of water inhibited an adequate transfer film, which increased wear for most materials. EAL lubrication showed a significant reduction in friction (up to 98%) when compared to dry conditions. The experimentally developed PPS composite provided superior tribological properties, especially under water-lubricated conditions.