Three teams will reportedly start the 2011 season without KERS.

The energy-recovery technology is returning to F1 this season in conjunction with a higher minimum weight and a fixed weight distribution.

But Auto Motor und Sport reports that all of the new-in-2010 teams - Team Lotus, Virgin and HRT - will be racing in Bahrain without a KERS boost button on board.

However, the report said Lotus' new TL11 car, to be launched on Monday, has been designed for a KERS system which will be fitted at some point during the forthcoming season.

Also designed to accommodate KERS for 2011 is the Cosworth engine that is used by Virgin and HRT as well as Williams, the famous British team that has designed its own battery KERS system.

Cosworth's business director Mark Gallagher said last year: "Our partners will be able to use KERS if they so choose."