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Plunged into darkness

The power failure witnessed on February 24, 2013, showed both the vulnerability of Pakistan’s electricity grids and the government’s incompetence in limiting power outages. Nearly every city in the country plunged into darkness.

The vulnerability of the country’s electricity grid is a well-known fact. Scientists and engineers have repeatedly raised the issue and warned the government of dire results, similar to the one witnessed on February 24.

Fortunately, there are solutions available that have been tried and tested in the rest of the world. All it takes is strong commitment and hard work to make the national electricity grid resilient to faults and failures. Since Pakistan’s power generation and transmission system is decades old, a complete overhaul is needed to turn the system into a dependable one. And the first aim of this effort would be to ensure that power blackouts of such magnitude never occur.

Unintended power blackouts typically involve a cascading failure in the electricity grid. A cascading failure occurs when one part of the grid system completely or partially fails, resulting in the shifting of its load to nearby systems in the grid. Those systems are then faced with electrical load, which is beyond their capacity, thereby causing them to fail as well. Consequently, their load in addition to the initial load, is shifted to systems further up in the grid which also fail and so forth. In more technical terms, the cascading failure in high voltage systems starts when a single point of failure on a fully loaded or slightly overloaded system leads to spiking across all the nodes in the grid. This leads to the failure of overloaded nodes which set-off more overloaded nodes, ultimately bringing down the entire electrical grid in a very short time.

With the susceptibility of electrical grids well-known, the solutions are present and have been implemented all over the world. Three well-known solutions are discussed here. First is changing the national macro-grid into micro-grids where each grid works independent of the other. In this case, if one grid fails, it will have no impact on its neighbouring grids. Second is turning the entire national grid into a smart grid in which latest technologies are used to continuously monitor the entire grid and computers control the system isolating a fault in real time before it spreads. The third is a hybrid grid, which incorporates both micro and smart grid properties. In the hybrid grid the national grid is subdivided into micro grids, but all of those grids are connected via a smart grid. This hybrid grid provides the best of all worlds.

The process of making the system resilient to cascading failure is quite complex since the failure spreads at the speed of light through the electrical transmission system. Even a computer would not be able to control it once it starts as the control signal would have the same speed as that of the failure speed – failure would outrun the control signal since it had a head start. Thus, the best option utilised is monitoring the entire grid within set limits, calculating in real time which element of the grid is nearing its limit and shutting it down before it crosses the safety limit. This helps stop the start of a cascading failure. This system is part of any smart grid.

However, computers alone cannot do all the work. Engineers skilled in smart grid technologies are needed to run them and can takeover once the computers point out an issue. Additionally, the engineers are needed to keep the computers and hi-tech systems running in optimal configuration.

The transmission system would also need to be upgraded to further enhance resilience and reliability. The next generation of electricity transmission systems are intended to be bidirectional, thereby allowing electricity generation at the household level. This would not only further enhance the system resilience but also allow users to sell electricity back to the utility company. Consumers are expected to generate electricity from fuel cells, solar cells and rooftop windmills. This would incorporate the concept of micro grids where a house would itself be a micro grid being able to send electricity to the national macro grid. Tomorrow’s transmission grids are expected to be able to handle bidirectional flow of electricity. Small power generation also encompasses the concept of distributed energy generation.

Blackouts being witnessed these days in sharp contrast to increasing energy demand and rising energy rates are making it imperative that Pakistan works out a comprehensive strategy to overcome them. While part of the issue could be resolved by increasing power generation capacity, it would also need upgrading of the transmission grid system to make it fault tolerant. It is imperative that while we are working to this end, we include cleaner fuels in our national energy mix as well.

To achieve this herculean task, a cooperative effort from all segments – the government, industry and society – would be needed. While at the government level, policies would be required, investment would be needed from the industry and efficient utilisation of energy systems would be needed from society.

The dark night of February 24 was of a scale never witnessed before in Pakistan. And if we do not wake up now and work tirelessly to fix our electricity grid, it wouldn’t be long when this type of darkness becomes routine, just as hours-long darkness has become a norm today.

The writer is a Ph.D. candidate.


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