In their General Terms & Conditions Contractors may cap Liquidated Damages at 20%

Higher Regional Court of Schleswig, Sentence dated 1 March 2012 – 5 U 47/11

In the General Terms and Conditions of a wind turbine supplier a clause capping liquidated damages due to non-availability of the turbines at an aggregate maximum of 20% of the estimated compensation for electricity fed into the grid is enforceable among business parties.