How to fit discrete optimization under a curve?

Hi all,

I am trying to fit discrete load under solar power curve. As show in the figure there is 2 discrete loads different sum (90%, 95%, 100%, and 105%)=alpa of the solar peak. Note here that the solar peak in normalized to 1.

Solar power is p(t), and [x1 x2]= [70,30]%

My question here is how to solve this for the optimal values of x's and optimal alpha ? And more over to look for more than 2 units up to 10 for example.

min(p-x1-x2) st x1+x2<=p x1,x2>0

Thanks for your help.

Regards, Habib