Living in Malaysia means dealing with the monsoon season. For many landed property owners, this raises a burning question: “Will my solar panels become useless when it rains?”

It’s a valid concern. You don’t want to invest in a system that stops working for half the year. However, the truth about Solar ATAP efficiency might surprise you. It’s not just about how much sun you get; it’s about how the billing rules work in your favor.

Yes, solar production drops during overcast or rainy days—typically generating 10-25% of their peak capacity. But here is the critical insight most installers won’t tell you: Maximum production isn’t always the goal; maximum utility is.

Under the current Solar ATAP framework, the “Use-it-or-lose-it” nature of certain export credits means that generating massive amounts of power on a sunny day isn’t helpful if you aren’t home to use it and the export rates are capped.

Here is the counter-intuitive truth about Self-Consumption vs. Export:

• Sunny Days (Export Scenario): You generate excess power while you are at work. This power is exported to the grid. If the credit cannot be stored indefinitely, you might “lose” that value.
• Rainy Days (Self-Consumption Scenario): You generate less power, but because you are likely using lights, fans, or appliances at home, you consume 100% of that energy instantly.

Every kilowatt you use directly from your roof saves you the maximum TNB tariff rate. In the “Solar ATAP” model, direct savings (self-consumption) beat export credits every time. Even on a rainy day, your system is actively lowering your bill.

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