Solar cell mistake problem

Problem statement

To date, the average electricity consumption of the USA is approximately 5´1011 W=500 Gigawatts. A beginner electrical engineer estimates the size of a square area in the state of Arizona to be covered with c-Si solar cells or with a-Si solar cells in order to fulfill this need.

The engineer intends to check all possible square areas from 1´1 to 150´150 miles, as well as all possible panel efficiencies from 1% to 20%. After that he/she would like to create a contour plot in order to observe how the required area increases/decreases depending on the available efficiency.

An older colleague from the same company has already started a MATLAB script for that purpose, which is given below. However, this colleague made four programming mistakes:

I have found 3/4 mistakes:

one in line 7, line 13 and in line 28. I think its in line 19 but i cannot figure it out. I put a (j) to make E(j) but cannot figure out what else.