Damn that's vague. So they can run no KERS again like last time ? But don't they increased the min weight of the car this season ? so no KERS might be too much of disadvantage ?
KERS is not mandatory, a number of the smaller teams have already come out and said they will not run it this year. And, yes, not having KERS will be a bigger disadvantage this year than it was in 2009 not just because of the minimum weight limit, but also because of new rules on weight distribution and the smaller front tires.
In 2009 the KERS cars actually started off with a big disadvantages relative to the non KERS cars because the weight of the KERS system meant they had less ballast to put towards the front of the car, which was required to get the best out of the fat Bridgestone fronts. In 2011 the front tires are not as fat as they were in 2009 and there is an enforced weight distribution as well.