An inventor called Jack Bitterly in a laboratory in Southern California has invented a flywheel made of densely packed carbon fibre that rotates at 100,000 revs per minute and as the wheel turns it generates electricity which could be used to drive an electric car. This story and stories about ancient inventions such as an aeroplane and an analogue computer can be viewed at https://youtu.be/bQJvyRLSl9U - allow an hour and a half to watch it. Very interesting.