PDB plans Tk870cr project to restore 20-30MW at Kaptai power plant

Highlights:

• BPDB proposes Tk869.97 crore to rehabilitate Kaptai's Units 4 and 5
• Units currently generate 20-30MW less than their combined capacity
• Ageing infrastructure, structural cracks and outdated systems threaten reliability
• Jica financing is considered, despite relatively high and rising interest rates
• Rehabilitation would restore the units' full 100MW generation capacity
• The project is planned for implementation from 2027 to 2029

The Bangladesh Power Development Board (BPDB) has proposed a Tk869.97 crore project to recover 20-30MW of generation capacity currently lost at units 4 and 5 of the Karnaphuli Hydroelectric Power Station in Kaptai, with Jica being considered as a source of financing.

Each unit has a generation capacity of 50MW but currently produces only 35-40MW because of extensive damage to structural components, ageing foundations, and outdated control systems.

The proposed project includes Tk656.98 crore in foreign debt, Tk200.58 crore in government funding, and Tk12.40 crore from BPDB's own funds.

Infograph: TBS

A Preliminary Development Project Proposal has been sent to the Planning Commission for approval in principle. The Power Division has also written to the Economic Relations Division (ERD) to secure financing from Japan International Cooperation Agency (Jica).

Jica's high-interest loans for project

ERD sources said Jica's loan interest rate will be 3.55% from next October, along with a 0.20% front-end fee. The rate is higher than those offered by the World Bank, the Asian Development Bank, and other bilateral development partners.

ERD officials said Japan's loan interest rate was below 1% even two years ago, but has since been revised every six months and could rise further.

Japan also provides project financing in several instalments rather than through a single agreement. As a result, each agreement carries the interest rate applicable at that time, creating a risk of further increases.

BPDB officials said several meetings had been held with Japan regarding the project and Jica had expressed interest in providing the loan.

However, financing could also be sought from the World Bank, the ADB or another development partner, with the government to make the final decision.

Ageing units face mounting technical problems

Units 4 and 5, each with a capacity of 50MW, were installed in 1988 and have been operating for about 37 years.

They have accumulated more than 1.66 lakh and 1.50 lakh operating hours, respectively, and generated over 12,500 GWh of electricity combined up to December 2025, according to project records.

The project proposal says both units now face serious technical problems, including cracks in key structural components, and damage to rotor rim supporting ledges.

Unit 5 has 10 damaged ledges, while Unit 4 has six. Ageing foundations have also distorted the stators and caused uneven magnetic forces.

The units' control and protection systems are outdated, while spare parts are difficult to obtain, making maintenance increasingly costly and inefficient.

Repeated welding of damaged components has further weakened the structures and increased safety concerns, according to BPDB officials. The PDPP warns that further deterioration could pose additional risks.

The Toshiba Corporation generators and Hitachi Ltd turbines have undergone several major maintenance and rehabilitation works over the years.

Hairline cracks in the rotor spokes were first detected in 2000 and repaired by Toshiba in 2006-07. A major overhaul was carried out in 2010-11 after the units exceeded the maintenance interval recommended by the original equipment manufacturer.

However, technical problems persisted. In 2017, a rotor rim supporting ledge in Unit 4 broke during operation, damaging the stator windings and causing a short circuit. Similar cracks were later detected in Unit 5.

Toshiba subsequently recommended full rehabilitation, but financial and logistical constraints prevented the work from being completed.

Instead, partial repairs, including coil replacement and welding of cracked components, were carried out to keep the units operational.

Several tenders for repairs and critical components were attempted between 2019 and 2022, but were cancelled due to a lack of competition and other constraints.

The units also have obsolete electrical and control systems. Their ageing analogue governor systems are increasingly difficult to maintain because spare parts are unavailable, making replacement with modern digital systems necessary for safer and more reliable operation.

Rehabilitation plan

The proposed rehabilitation aims to restore the units' full 100MW capacity, improve safety and ensure reliable operation. A detailed technical study is also planned to identify the causes of the damage and develop long-term solutions.

According to the PDPP, the project is scheduled to run from January 2027 to December 2029. It will largely use the existing power evacuation system, with upgrades where necessary.

The work will include rehabilitation or replacement of major generator components, including stator coils, rotor poles, wedges and insulation, as well as turbine runners, shaft seals, cooling and drainage systems and bearings.

The project will also upgrade the governor, automation, electrical, excitation and auxiliary systems, alongside training and commissioning works.

BPDB officials said rehabilitating existing plants is necessary alongside building new capacity as electricity demand grows.

They said timely implementation would help prevent further deterioration, reduce the risk of major mechanical failure and preserve the power station as a national asset.