In a letter to the team principals, seen by Pitpass, FIA President Max Mosley has revealed a timetable for the evolution of Kinetic Energy Recovery Systems (KERS) over the next few years.

Stressing that the proposals are "for discussion", Mosley writes: "It has become clear that it is important to decide how KERS should evolve over the next few years. We should therefore like your views on how to proceed."

As from 2009, Mosley suggests that teams will be allowed to extract 60kW of energy from one axle on their cars, allowing drivers access to 400kJ of energy per lap, which would be used in the form of a 'boost' button.

By 2011, Mosley suggests this could be increased to 100kW, giving drivers access to 800kJ per lap, and by 2013 this would increase to 200kW (from two axles) giving drivers 1.6MJ per lap.

This would coincide with the introduction of the new low-cost engine in 2013 when the homologation of the current units runs out in 2012.

Mosley adds: "In addition to KERS, we think it would be interesting to allow the recovery of a maximum of 20KW from the cooling system from 2011. The suggestion is that this power would feed continuously into the drive train. Heat recovery would, of course, be an entirely new, road-relevant technology. The idea is to allow it but not to require it.

"Then, in 2013 the new engine would also allow exhaust energy recovery," he adds.

Mosley is at pains to point out that the proposals are merely "for discussion" and "not intended as a statement of policy" suggesting that Tony Purnell and Peter Wright are available for "detailed discussions. However, he makes it clear that he hopes to be able to agree the "broad direction" of the plan when the World Motor Sport Council meets in June.