Architect Claire Price talks about the field of energy harvesting and looking at ways to tap into the energy available from the workings of the human body or transport vibrations. Originally a DARPA-inspired area of research, imagine "34,000 commuters who pass through Victoria underground station at rush hour, for example, [who] could theoretically generate enough energy to power 6,500 LED light fittings - energy that today is disappearing into the ground." Read more of his ideas in the BBC.