Potential Energy is calculated through the equation,
 PE = m x g x h 
where m is the mass, g is the acceleration due to gravity, and h is the height. Since, weight is equal to mass times gravity, PE may also be calculated through the equation,
 PE = W x h
Substituting the known values,
 PE = (2,200 N) x (15 m) 
 PE = 33,000 J