Villa in Rawai, Phuket

1. About the project

What the system delivers

• Covers around 74% of electricity consumption.
• Estimated savings of THB 67,000 per year.
• Payback on the panels, inverter and battery in approximately 4 years and 10 months.

Solar energy with clear financial benefits

The client already knew the benefits of solar panels. However, he believed that adding a battery would make the system too expensive and that the investment would not pay off.

For his villa in Rawai, we selected a hybrid system that makes solar energy available both during the day and after sunset. The PVsyst calculation demonstrated the financial case for including a battery: around THB 67,000 in annual savings and a payback period of less than five years.

2. The challenge and objective

Showing when a battery justifies the investment

After comparing offers from other companies, the client approached Siriteja with a request for a “10/10/10” system: solar panels, an inverter and a battery. He wanted to understand how a battery would benefit his particular home and how quickly the entire system would pay for itself.

Our task was to match the equipment to the villa’s electricity consumption and present the cost, expected savings and payback period before installation.

3. Engineering solution

Solar energy during the day and in the evening

We combined solar panels, a hybrid inverter and a battery into one energy system. During the day, solar generation powers the home, while some of the energy is stored in the battery for use in the evening.

The battery makes more of the home’s own generation useful: energy produced during the day remains available after the sun has set.

4. Solar generation and energy storage

15 Trina panels: 9.375 kW

The 625 W solar panels are installed on the roof slopes. Their combined capacity is 9.375 kW.

Deye hybrid inverter: 10 kW

The inverter coordinates the solar panels, battery and utility grid, directing energy to household consumption and battery charging.

GENIXGREEN battery: 10.24 kWh

The lithium battery stores daytime energy for evening consumption and helps reduce electricity purchases from the utility grid.

5. System protection

The system includes electrical protection for the solar and grid circuits, as well as control of energy export to the utility grid. Equipment protection and correct connections are just as important to the solution as the panels and battery.

6. System economics

Cost and savings

• System cost including VAT: THB 324,480.
• Share of electricity consumption covered: around 74%.
• Savings: THB 67,000 per year, or around THB 5,600 per month.
• Estimated payback period: 4 years and 10 months.

The figures were calculated using the villa’s consumption profile and an electricity tariff of THB 4.7/kWh. They represent the system’s expected financial performance.

7. Project results

For this villa, the battery became part of a financially justified solution. It makes solar energy available after sunset and increases the value of the home’s own generation. The calculation showed that the investment in the panels, inverter and battery would pay back in approximately 4 years and 10 months.

The result starts with understanding how a home uses electricity. That is why we select a system to match the owner’s consumption and explain its economics in advance.

Who is this approach suitable for?

• Private homes and villas that use electricity during the day and in the evening.
• Properties where using more of their own solar energy is a priority.
• Owners who want to understand the system’s economics before investing.

Would you like a similar solution for your property?

We will analyse your home’s electricity consumption, select solar panels and a battery, and show the expected savings and payback period.