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Oral reply to PQ on electricity disruption

Oral reply to PQ on electricity disruption


Mr Desmond Choo: To ask the Minister for Trade and Industry (a) what is the cause of the widespread electricity disruption that occurred on 18 September 2018; (b) how are our critical infrastructure protected against such disruptions; and (c) what is the impact of the liberalization of the energy market on the reliability of electricity provision.

Mr Liang Eng Hwa: To ask the Minister for Trade and Industry (a) what is the root cause of the major disruption to power supply in Singapore on 18 September 2018; and (b) what are the follow-up actions and measures that will be put in place to minimize the risks of recurrence.

Assoc Prof Daniel Goh Pei Siong:
To ask the Minister for Trade and Industry what caused the power failure on 18 September 2018 and how many homes were affected by the blackout.

Ms Rahayu Mahzam: To ask the Minister for Trade and Industry (a) what are the findings from the investigations by the Energy Market Authority on the disruption of power supply that occurred on 18 September 2018; (b) what are the safeguards that are in place to ensure that there are no power disruptions to critical services such as those in hospitals, lifts, street lights and traffic lights; and (c) what are the safeguards that can be put in place to prevent another similar occurrence of disruption of power supply in the future.

Oral reply (to be attributed to Senior Minister of State for Trade and Industry Dr Koh Poh Koon)

1.             Mr Speaker, let me begin by tracing the timeline of events behind the electricity supply disruption on 18 September.

2.             That evening, a total of 16 generating units were operating. At 1:17am, a power generating unit at Sembcorp Cogen Pte Ltd tripped. Based on EMA’s preliminary investigations, this was likely due to an equipment fault. This triggered an automatic response by the other 15 units to increase their supply, to meet the demand for power. This is usually not a problem, as each of the remaining units only had to increase their supply by about 5%. However, a unit at Senoko Energy Pte Ltd tripped a few seconds later, due to failure of a different equipment component. This led to a further shortfall in supply from the operating plants to meet demand, which caused the protection devices in the power system to kick in as designed and automatically disconnected electricity to about 146,500 consumers to rebalance the system. Out of the 146,500 consumers affected, 130,535 were households.

3.             To restore electricity supply, EMA immediately instructed other stand-by generating units, including unaffected units from Senoko and YTL PowerSeraya Pte Ltd to provide additional electricity supply. Once these additional units came online after about 15 minutes, electricity supply was progressively restored. While power was fully restored within 38 minutes, some consumers remained affected as the electrical equipment within their premises had to be manually reset.

4.             EMA treats its mandate of ensuring the reliability of Singapore’s electricity supply very seriously, and has taken the following steps in response to this incident.

5.             Firstly, EMA has been working closely with the two generation companies and their original equipment manufacturers to establish the root cause of their respective equipment failures, even though the units were maintained in accordance with the manufacturers’ recommendations. This is important because the generation technology is used in other generating units in Singapore as well as globally, and what happened here could occur elsewhere. This will take some time, as the parts have to be sent for testing overseas, but we believe a thorough investigation is important.  

6.             Secondly, EMA is also working with the industry to review its processes for handling such events to ensure they remain satisfactory. As explained earlier, the technical processes kicked in as designed, allowing for the relatively quick restoration of power. During the blackout, SP Group officers were immediately activated and deployed at key substations and control centres. SP Group also provided the public with progressive updates on its social media channels and concurrently informed the media of its updates. Nonetheless, we will review this incident carefully, to see how we can further improve our responses.  

7.             Thirdly, we are reviewing our system to ensure that we continue to have sufficient capacity and contingency measures to handle any similar incidents in future. Mr Speaker, I would like to reassure the House that we do have enough spare capacity in our system, as evidenced by the quick progressive restoration of power within 15 minutes of the incident. In the design of any electricity grid system, we have to balance redundancy and assurance with cost imposed on consumers. The higher the degree of redundancy, the smaller the probability of disruption, the higher the cost at the system level. Hence we have adopted a calibrated approach in our system planning, with a certain level of redundancy at national grid level, coupled with a higher level of redundancy at the local level for critical systems. This system design has served us well so far, with Singapore having one of the most reliable and affordable electricity systems in the world. From FY13 to FY17, the average disruption per consumer annually in Singapore ranged from 12 to 45 seconds. In comparison, major cities such as Tokyo, New York, Hong Kong and London experienced an average disruption per consumer of between 4 and 34 minutes in 2015.

8.             The reliability of electricity supply has also not been affected by the liberalisation of the electricity market. In fact, our electricity sector relies on both regulatory powers and market incentives to keep generation companies on their toes. Generation companies that do not maintain their sets will lose market share and face regulatory action by EMA. In addition to the generation companies, EMA also regulates the infrastructure planning and maintenance regime of SP PowerGrid, the national grid operator, to improve system reliability and minimise disruptions. 

9.             For critical services and infrastructure, such as lifts, traffic signalling systems and public hospitals, these have contingency plans to deal with power outages on the national grid. For instance, public hospitals are provided with dual supply sources, each of which is able to provide backup to the hospital if the other one fails. In addition, if there is any disruption from the main power source, backup power systems, such as diesel generators and Uninterrupted Power Supplies (UPS) systems, would automatically kick in, to support all critical equipment and critical facilities. Hospitals also carry out regular and preventive maintenance to ensure that both their electrical installations and backup power systems are in good working condition. During the power outage on 18 September, hospitals in the affected areas activated their back-up power supply immediately, preventing disruptions to their operations and patient care. Telecommunication exchanges similarly did not experience any disruption as their back-up power supplies were activated. 

10.          On the other hand, passenger lifts have to be installed with an Automatic Rescue Device that will park the lift at the nearest floor and open its doors during a power failure. Furthermore, a standby generator is required for lifts in very high-rise residential buildings or those serving both residential and non-residential uses, which will provide emergency power to resume at least one lift’s operations. As for traffic signals, LTA will work with the Traffic Police to quickly deploy resources where needed during a power outage, to assist with traffic control at affected junctions. Backup generators can also be deployed on-site to provide temporary power supply to mitigate the impact to traffic signal operations.

11.          Beyond these sector-specific measures, EMA has been looking at how technological solutions such as energy storage systems can increase security and resilience at the system-level. Such technologies can also address other issues such as the increased intermittency faced by greater deployment of intermittent generation sources such as solar power. EMA recently completed a round of industry consultation on the regulatory framework for energy storage systems and will publish a policy paper to provide clarity on the regulatory framework by 4Q 2018.

12.          We will ensure that we incorporate all the lessons from this incident to ensure continued high standards of reliability for our power system.
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