Thanks to TS for opening this discussion and the posters on the first 2 pages for their discourse, I think I understand how TNB calculates this and have an idea on why it is done this way.

It seems to me that there is still ROI in solar installation however people need to understand that using solar that is tied to TNB grid does not mean they can use more electricity freely where the cap is 1500kWh. On one side I like how this causes us to be green and think about what our big energy expenditures are like AC. On the other side it does feel like a detriment to going green by using EV. I suppose the purpose cant be any clearer, I am charged more when I use more electricity because the grid needs to cater to my usage and TNB needs to invest to handle that load, regardless of how much I return to the grid.