Need to consider also how long solar panel and batteries can last before replacement.

Yes, for RM 400-600 bill you need 10 kwp setup.
Which is around 45,000.00
Takes 6-7 years to recoup the investment.

But, there is a big BUT, this NEM policy stays valid for 10 years only.
After ten years, you can't sell it back to TNB anymore to offset your bill.

The way out is installing another battery setup (20-40k) depends on cost of the battery 10 years later.

I roughly did my calculation previously,
for 20 years with 10 years of NEM policy (sell back to TNB) and
10 years of self consumption (Install battery after 10 years),
the CAGR is around 5.5%,
which can be easily achievable by putting the money in EPF plus without any headache.

Meaning same amount of money put in EPF, get you same return like Solar Project.

Correct me if my calculation is wrong.

If no batteries, how to get power at night? During day, where to channel excess power if not storage. Panel output is DC anyway and output is not constant. The AC is generates using inverter from DC.

your monthly electric bill high then worth la.

if monthly bill around RM50-80 nia not worth

before getting ROI need to pay for maintenance liao