As a major economy in Southeast Asia, Thailand has a continuously growing demand for electricity. Coastal gas-fired and coal-fired power plants, relying on convenient seawater resources, generally adopt seawater cooling systems. However, the high-temperature and high-salt environment of tropical marine areas leads to prominent problems of biological fouling in cooling pipelines. Traditional liquid chlorine disinfection has potential safety hazards and environmental risks. Seawater electrochlorination technology, which generates sodium hypochlorite by on-site electrolysis of seawater, provides an innovative solution to this problem and is showing unique application value in Thai coastal power plants.
Technical Principles and Core Advantages
The core principle of seawater electrochlorination technology is to use electrolytic cells to convert chloride ions in seawater into sodium hypochlorite with strong oxidizing properties. During electrolysis, when seawater passes through titanium-based coated electrodes (DSA anodes), chloride ions lose electrons at the anode to form chlorine gas, which reacts with water to form hypochlorous acid (HClO) and hypochlorite ions (ClO⁻). These two components can effectively destroy microbial cell membranes and inhibit the reproduction of marine organisms such as algae and barnacles. The entire system consists of four parts: electrolytic cell, rectifier, brine supply unit, and control system, which can automatically adjust the electrolytic current according to the cooling water flow rate to achieve precise dosing.
Compared with traditional disinfection methods, this technology has three major advantages in Thai power plant applications: in terms of safety, on-site chlorine production avoids the explosion risk of liquid chlorine transportation and storage, complying with the strict requirements of Thailand's "Industrial Safety Law" on hazardous chemical management; in terms of economy, using the power plant's own electricity resources to produce disinfectants reduces the cost per ton of available chlorine by 30% compared with purchased liquid chlorine. For large power plants with an installed capacity of over 1000MW, the annual cost savings can reach millions of baht; in terms of environmental protection, sodium hypochlorite naturally decomposes into sodium chloride in water without residual pollution, and the residual chlorine concentration in discharged water can be controlled at 0.1-0.2mg/L, meeting the discharge standards of Thailand's "Marine Environmental Protection Regulations".
Application Scenarios in Thai Coastal Power Plants
The Map Ta Phut Industrial Zone in Rayong Province, part of Thailand's Eastern Economic Corridor (EEC), is a key application area for seawater electrochlorination technology. This area gathers several combined-cycle gas-fired power plants operated by companies such as Gulf Energy and IRPC. The length of their seawater cooling system pipelines is mostly more than 10 kilometers. Pipeline blockages caused by biological fouling once reduced the unit thermal efficiency by 5%-8%. After a 3.6GW gas-fired power plant introduced a seawater electrochlorination system provided by a Chinese enterprise, efficient operation was achieved through the following processes:
Seawater enters the electrolytic cell after being filtered by a grille. Under a 3000A current, a 0.8% concentration sodium hypochlorite solution is generated, which is injected into the inlet of the cooling system by a metering pump at a dose of 1.2mg/L; an online residual chlorine monitor is installed in the middle section of the circulating water pipeline, and the data is transmitted to the PLC control system in real-time. When the residual chlorine concentration deviates from the set value, the system automatically adjusts the electrolytic current; an activated carbon adsorption device is installed at the outlet of the cooling system to ensure that the residual chlorine concentration in the discharged water is ≤0.1mg/L. After the system operated for one year, the thickness of biological fouling on the inner wall of the pipeline was reduced from 3-5mm to less than 0.5mm, the unit thermal efficiency was restored to the design value, and the annual downtime for cleaning was reduced by about 120 hours.
The Bang Pakong Power Plant in Chonburi Province has combined seawater electrochlorination technology with intelligent management. This power plant with an installed capacity of 1862MW, during its 2024 renovation, interconnected the electrochlorination system with the plant's DCS system, achieving the following innovations: automatically adjusting the chlorine dosage according to changes in turbine load (for every 10% increase in load, the chlorine dosage increases by 8%); combining with seawater temperature sensor data, automatically activating the enhanced disinfection mode in summer (when water temperature ≥32℃); predicting the biological fouling trend through AI algorithms and adjusting operating parameters 24 hours in advance. After the renovation, the maintenance cost of the cooling system of this power plant decreased by 40%, becoming a demonstration case promoted by the Electricity Generating Authority of Thailand (EGAT).
Application Challenges and Countermeasures
Thailand's tropical climate brings special challenges to the application of seawater electrochlorination technology. The average annual seawater temperature above 30℃ accelerates electrode loss, and the service life of traditional titanium-based electrodes is shortened from 5 years in temperate regions to about 3 years. In response, Thai power plants mostly use ruthenium-iridium-titanium ternary coated electrodes. By increasing the content of precious metals (iridium content reaches 20%) to enhance corrosion resistance, the electrode service life is extended to 4.5 years. Operational data from a power plant shows that although the purchase cost of new electrodes increases by 25%, the full-life cycle cost is reduced by 18% due to fewer replacements.
High seawater turbidity is another major problem. In power plants near the estuary of the Chao Phraya River (such as the South Bangkok Power Plant), the concentration of suspended solids in seawater can reach more than 50NTU during the rainy season, which is very easy to cause blockage of the electrolytic cell. Solutions include: adding an automatic backwash filter before the electrolytic cell with a filtration accuracy of 50μm; adopting a pulse electrolysis mode, shutting down for 10 minutes every 4 hours of operation, and using reverse current to remove deposits on the electrode surface; regularly (once a month) cleaning the electrolytic cell with 5% dilute hydrochloric acid to maintain the current efficiency above 90%.
The increasing requirements for environmental compliance have also prompted technological upgrading. Thailand's revised "Industrial Wastewater Discharge Standards" in 2024 added a total organic carbon (TOC) control index, requiring the TOC of cooling system discharge water to be ≤5mg/L. For this reason, a waste incineration power plant innovatively combined seawater electrochlorination with ultraviolet disinfection. First, sodium hypochlorite generated by electrolysis removes 90% of microorganisms, and then ultraviolet rays (dose 30mJ/cm²) degrade residual organic matter. Finally, the TOC of the discharged water is stabilized at about 3.5mg/L, far exceeding the standard requirements.
Future Development Trends
With the advancement of Thailand's goal of "51% renewable energy share by 2037", seawater electrochlorination technology is developing towards greenization and intelligence. In terms of green energy integration, a biomass-gas combined power plant in Rayong Province has tried to connect photovoltaic power to the electrochlorination system. By balancing the fluctuation of photovoltaic power generation through energy storage batteries, the carbon emissions from disinfectant production have been reduced by 22%. This model has obtained the green technology certification from the Thailand Board of Investment (BOI) and enjoys income tax reduction and exemption benefits.
Intelligent upgrading is reflected in the application of digital twin technology. The "Virtual Electrolytic Cell" system being tested by the Provincial Electricity Authority (PEA) of Thailand can simulate the impact of different seawater parameters (salinity, temperature, pH value) on disinfection effects through digital models and optimize operating parameters in advance. Data from a pilot power plant shows that this technology has improved the chlorine dosage control accuracy to ±0.05mg/L, further reducing chemical consumption by 15%.
Sino-Thai technical cooperation has also injected new vitality into this field. The "Sino-Thai Seawater Electrochlorination Joint Laboratory" signed in 2025 plans to establish a research and development center in Bangkok, focusing on the development of low-energy electrolytic cells suitable for tropical environments (aiming to reduce the energy consumption per unit chlorine production from 4.5kWh/kg to 4.0kWh/kg) and anti-biological fouling electrode materials. These innovations are expected to increase the popularity of seawater electrochlorination technology in Thai coastal power plants from the current 35% to more than 60% by 2030.
Chlory has been deeply engaged in the field of seawater electrochlorination technology, continuously making efforts in research and development and practical application. The successful application cases of Thai power plants fully prove that through localized technical optimization and innovation, this technology can efficiently overcome the problem of biological fouling in cooling systems in tropical coastal areas. With increasingly stringent environmental regulations and the vigorous development of intelligent technologies, seawater electrochlorination technology is gradually becoming the core driving force for the green transformation of Thailand's power industry, and the accumulated practical experience will also provide a highly valuable "Thai model" for coastal countries in Southeast Asia.
The seawater electrochlorination system developed by Chlory, with advanced technology and stable performance, has achieved large-scale application in Southeast Asian countries such as Thailand, Indonesia, the Philippines, and Vietnam. Its application scenarios cover power plant circulating water systems, municipal water treatment plants, and industrial wastewater treatment plants, providing reliable guarantees for equipment anti-corrosion and microbial control in various industries.