Chokphoethong Bottling Plant 198kWp Solar PPA — Si Racha

Project Overview

Chokphoethong Transport 2012 Co., Ltd. operates a water bottling and distribution facility in Si Racha, Chonburi — running 24 hours a day, seven days a week. With monthly electricity bills consistently exceeding THB 300,000, the business was paying one of the highest ongoing costs of any operation its size. As an industrial-scale TOU (Time of Use) tariff customer on a 22–33kV connection, they were being charged peak rates of over 4.18 THB per kWh for daytime consumption — exactly the hours when solar generation is at its highest.

Kunini Solar EPC was engaged to design, fund, install, own, and operate a 198kWp rooftop solar system under a Private Power Purchase Agreement (PPA) — allowing the business to access the benefits of solar with zero capital expenditure and no technical burden.

The Challenge

The facility’s large corrugated metal roof required a robust, non-penetrating mounting solution that would not compromise the roof’s integrity or the plant’s watertight requirements — a critical consideration for a food-grade production facility. With operations running around the clock, installation had to be managed carefully to avoid disrupting production below.

The scale of the system — 198kWp across a single roof structure — also required a detailed structural engineering assessment, precise string design across 18 DC combiner circuits, and full PEA compliance documentation for a Medium Voltage (22–33kV) interconnection, which involves more complex grid protection requirements than a standard Low Voltage connection.

The Kunini Solution

Kunini’s in-house engineering team designed a 198kWp system using approximately 307 LONGi 645W monocrystalline panels, mounted on Antai metal roof clamps — a zero-penetration mounting solution that preserves the roof membrane and carries no structural load beyond the design capacity of the existing purlins. A central safety walkway with fiberglass anti-slip grating runs the full length of the ridge, providing safe access for ongoing O&M.

A Solis 150kW commercial three-phase inverter was selected for its proven reliability in industrial environments and its native compatibility with the facility’s 22–33kV metering setup. An 18-string DC combiner box, custom AC solar panel, and DC solar panel were engineered and installed in a dedicated inverter room adjacent to the main electrical switchroom. A crane was deployed to lift panels to roof level efficiently, allowing the installation to be completed without disrupting plant operations below.

As the system owner under the PPA agreement, Kunini manages all ongoing performance monitoring, maintenance, and insurance throughout the contract term. Chokphoethong pays a fixed monthly PPA service fee for the solar energy delivered — replacing a portion of their grid electricity spend with a predictable, lower-cost alternative.

The Result

The system generates approximately 25,000 kWh of clean solar electricity per month — offsetting around 33–35% of the facility’s total grid consumption. Given that the plant operates continuously, the solar system delivers its generation entirely during peak daytime tariff hours, where the grid rate exceeds 4.18 THB/kWh — maximising the value of every kilowatt-hour produced.

The facility’s first PPA invoice was issued in August 2026 following commissioning, replacing what would otherwise have been a significant portion of their monthly PEA bill. With the PPA rate locked in below current grid tariffs, the business now has greater electricity cost predictability for planning purposes — regardless of future Ft charge adjustments.

A Phase 2 expansion to increase system capacity is currently under assessment, planned for Q4 2026, as the business continues to grow its production volumes.

System Highlights

Is a Private PPA Right for Your Business?

If your monthly electricity bill exceeds THB 80,000 and you have suitable roof space, Kunini can assess your site and model a PPA proposal at no cost. Zero upfront investment. Immediate savings from day one.

Hua Hin: +66 (0) 61 413 4850

Pattaya / Si Racha: +66 (0) 82 056 7906

Email: info@kunini.com

Web: www.kunini.com