Ford Motor Company has decided that its third generation hybrid vehicle system will replace nickel-metal-hybrid batteries with lithium-ion batteries. This could reduce the company's use of "rare earth" metals such as neodymium, cerium, lanthanum, and praseodymium, by up to 500,000 pounds per year.

The company has already reduced its use of dysprosium by about 50% in magnets for hybrid vehicles. "We're continually looking to find ways to provide greater fuel efficiency as well as cost savings to customers of our hybrid vehicles, and the reduction of rare earth metals is a key part of this strategy," said Chuck Gray, chief engineer, Global Core Engineering, Hybrid and Electric Vehicles. It remains unclear to me which of these are "rare" because that is merely their name, and which are rare and therefore potentially could be very expensive as demand increases.