Power Felt is a thermoelectric fabric being developed by a team at Wake Forest University, North Carolina. It uses carbon nanotubes to create an electrical charge from temperature differences, with possible use cases include warming clothes, charging mobile devices, and storing heat through insulation in pipes and roof tiles. The material apparently feels just like felt, so clothing would be a good fit — it differs from technology such as piezoelectronic textiles in that no movement is required to generate a charge. While Power Felt is still being refined, the team envisions a future where the technology could be cheap and ubiquitous, for example only adding a dollar or so to the cost of a mobile phone cover.