A fault in the national grid disrupted electricity supply across Sri Lanka last Saturday, leaving the country without power for more than two hours. Although no definitive cause has been identified, officials involved in the country’s power distribution and transmission believe the situation may have been triggered by excess solar power capacity connected to the grid relative to demand.

Sri Lankan utility companies have since ordered the temporary suspension of rooftop solar power systems. The country’s national grid also suffered a complete shutdown in February last year, when excessive pressure from solar power reportedly destabilised the system and led to a grid failure.

The Bangladesh government aims to develop around 10,500 megawatts of renewable power generation capacity by 2030. Electricity from the country’s nuclear power plant is also expected to be connected to the national grid within this year. Experts have expressed concern over whether the grid is sufficiently prepared to accommodate electricity generated using these advanced and emerging technologies. They say Bangladesh should place greater emphasis on expanding grid capacity and modernising the system, taking into account its past experience of grid failures and accidents involving new power technologies in other countries.

They also stress the need to properly follow existing integrated management systems and policies designed to protect the grid from power generation through to distribution. Such measures, they believe, could help prevent power outages and major grid accidents.

Officials from Power Grid Bangladesh PLC and the Bangladesh Power Development Board (BPDB) said they are continuously working to address grid-related accidents, failures and technical faults. They identified spinning reserve as a key challenge, saying that addressing the issue could reduce risks across large sections of the grid.

Bangladesh has experienced several grid failures over the past few years. The main causes broadly include technical faults, weaknesses in the transmission system, and imbalances between electricity supply and demand. First, a grid failure can occur when electricity supply does not match consumer demand.

Second, cascading tripping occurs when a major power plant or transmission line suddenly shuts down or trips for any reason, placing additional pressure on other lines. This can trigger the automatic shutdown of power plants and substations one after another.

Third, weaknesses in the transmission system and inadequate maintenance have contributed to major failures in the past. Poor maintenance of the power grid, along with capacity limitations in ageing transmission lines and substations, has increased the risk of disruptions. In October 2022, faults at the Ghorashal power plant and Aminbazar substation, or a fire involving a transformer, led to a nationwide grid failure.

The government plans to connect electricity from the Rooppur Nuclear Power Plant in Pabna to the national grid either later this year or early next year. Power from the state-of-the-art plant, which has a capacity of 1,200 megawatts, will be integrated into the grid in phases. Several transmission lines have already been built to carry electricity from the plant. But Russia’s state-owned nuclear energy corporation Rosatom, the plant’s builder, has repeatedly advised maintaining an adequate spinning reserve before commissioning it. The Bangladesh Power Development Board (BPDB) has said that maintaining such a reserve remains a major challenge.

Bangladesh’s current power generation capacity stands at 29,593 megawatts. Of this, grid-connected renewable energy accounts for 1,229 megawatts, or 3.81 percent of the total capacity. If the existing capacity is maintained and another 10,450 megawatts of renewable energy capacity is added to the grid by 2030, the country’s total power generation capacity will reach around 40,000 megawatts.

Experts warn that maintaining grid stability could become extremely difficult if the full capacity of renewable energy — most of it solar power — is used during the day and a large share of solar generation drops off the grid towards evening. The challenge will be particularly acute if other energy sources cannot immediately make up for the shortfall.

Experts say integrated management is essential to maintaining grid stability and preventing grid failures, and also stress the need to modernise the grid and develop spinning reserves and battery storage systems.

Speaking to Bonik Barta, Dr Abdul Hasib Chowdhury, a professor in the Department of Electrical and Electronic Engineering at Bangladesh University of Engineering and Technology (BUET), said, “Grid stability requires integrated management of power generation, transmission and distribution. Reliability and resilience must be ensured at every stage. With nuclear power and large-scale renewable energy set to enter the generation mix, greater emphasis must be placed on efficient technical management across all three stages.”

M Rezwan Khan, former chairman of Power Grid Bangladesh PLC and professor emeritus at United International University, also stressed the importance of storage capacity for solar power and grid management as electricity generated using advanced technologies is connected to the national grid.

Speaking to Bonik Barta, he said, “New power plants using advanced technologies are being connected to the grid, and larger solar power plants will be added in the future. Once these plants are integrated into the grid, its stability will become a major concern. In this context, spinning reserves and battery backup have become essential. I’m not saying that our grid is risk-free, but it has the capacity to withstand disruptions. Grid modernisation must therefore continue to advance gradually. This will require substantial investment, which will have to be made in phases.”

He added that greater caution was needed in managing the grid as electricity from various technologies was being integrated into the system. Ensuring grid stability, he said, was essential for accommodating these new sources of power.

Former senior officials of state-run agencies working in the sector also believe the grid needs to be upgraded to successfully integrate renewable electricity.

Mohammad Alauddin, former chairman of the Sustainable and Renewable Energy Development Authority (SREDA), told Bonik Barta, “The government’s renewable energy target is undoubtedly commendable. But expanding capacity also depends significantly on the grid, and the system must be upgraded accordingly. Focusing solely on power generation won’t be enough; investment in battery storage systems is also necessary so that batteries can provide backup if generation-related problems arise on the grid. This will require substantial investment.”

“There would have been little reason to worry about battery backup in Bangladesh if a SAARC regional grid network could have been established. Under such a network, if a fault occurred in one country’s grid, electricity could be supplied using backup power from another country.”

Bangladesh’s power grid currently has 18,817 circuit kilometres of transmission lines. Over the past five years, another 5,496 circuit kilometres of 400 kV, 230 kV and 132 kV lines have been built. Substations operating at 230 kV, 132 kV and 33 kV have also been constructed. Power Grid officials said these transmission infrastructure projects represent a major part of the grid’s modernisation.

Conversations with several Power Grid officials revealed that the country’s transmission network still contains considerable amounts of ageing infrastructure and old lines, contributing to significant transmission losses. Transmitting electricity from 400 kV lines to lower voltage levels poses particular challenges for the grid. Faults also occur when electricity is delivered from the transmission network to the distribution level.

Power Grid is modernising its network and building new transmission infrastructure. But officials warned that risks to the overall system would remain unless modernisation efforts were expanded more extensively at the distribution level.

A senior Power Grid official, who spoke to Bonik Barta on condition of anonymity, said maintaining spinning reserves was a major challenge to grid stability, adding that the responsibility did not lie with Power Grid. “If spinning reserves can be maintained properly, most grid failures can be avoided. We’re holding regular meetings on the issue and informing the ministry. Power Grid is also recommending storage systems for solar power to ensure uninterrupted integration of electricity generated using new technologies. PGCB itself has undertaken a pilot project to install battery storage capacity of 200 megawatts at Ishwardi and Ghorashal,” he said.

Asked how BPDB was working to ensure grid stability, its chairman, Engineer Md Rezaul Karim, told Bonik Barta, “A study is underway on the grid’s capacity and stability, with a focus on identifying its weaknesses. Work is also underway to determine what further measures can be taken to increase grid capacity. Two meetings have already been held. Utility companies, PGCB and BPDB, are gradually discussing how much nuclear and solar power will be added to the grid each year as these sources are integrated in phases.”