Most pro-forma look like this: Take year-1 generation → apply degradation curve → haircut for availability → extrapolate to 30 years in a spreadsheet.

But over 30 years, uncertainties interact and compound:

• Weather varies year over year 

• Modules degrade unevenly, creating growing mismatch losses

• Degradation shifts the energy production curve, changing when clipping occurs

• Grid curtailment eats into revenue generating electrons

Simple extrapolation can't capture these interactions. Overconfident P50 estimates lead to portfolio shortfalls and underestimated P90 in poorly secured debt.