According to a UN report, natural disasters in the last decade have occurred almost twice as often compared to two decades ago, with Asia being the hardest hit. The report reveals that the number of such events had gone up 14% annually between 2005 and 2015 compared to the period 1995-2014. Such findings have driven countries like UK and USA to accelerate their resilience building measures. ‘Resilience’ implies preparedness and having a robust coping mechanism to deal with the damage wrought by hurricanes, earthquakes, floods and other violent natural events. The United Nations Office for Disaster Risk Reduction (UNISDR) has even launched a campaign called Making Cities Resilient which suggests, among other things, increasing the resilience of infrastructure for crucial services including electrical power, transport, healthcare and telecommunications.
India’s vulnerability to natural disasters
The UN report lists India as third among the countries hit by the highest number of weather related disasters in the past decade. The Center for Research on the Epidemiology of Disasters in its Annual Disaster Review for 2014 also listed India among the five countries most frequently hit by natural disasters.
According to the National Cyclone Risk Mitigation Project, almost 5,700 kilometers of India’s 7,500 kilometers of coastline are highly vulnerable to the impact of tropical cyclones and related meteorological hazards. Research by Verisk Maplecroft also shows that 82% of the population in India are exposed to natural hazards, compared with 50% of the population in China.
What is also disturbing is the increased vulnerability of populous Indian cities to the effects of these natural disasters, caused by growing population density, haphazard construction activities and inadequate preparedness. The recent Mumbai floods which crippled the city in August 2017, for example, were exacerbated by the city’s out-of-date drainage system and unbridled construction over the city’s natural nullahs, which otherwise could have effectively drained excess water. A report on World Disasters by the International Federation of Red Cross and Red Crescent Societies (IFRC), lists Mumbai among the 10 most vulnerable cities in terms of floods and earthquakes. A survey shows that, on an average, 21 Indian cities scored between 2.5 to 4 points out of 10 on governance parameters that measure preparedness for disasters.
Regions like the North East in India are particularly susceptible to natural disturbances like earthquakes, floods and landslides. According to the National Flood Commission, Assam, for example, accounts for 9.4% of the total flood prone area in the country. The commission estimated that due to floods, Assam suffered a loss of Rs, 3,100 crores in the past five decades. The whole of Brahmaputra Valley in Assam is in fact considered one of the most hazard prone regions in the country, with more than 40% of its land (3.2 million hectares) being susceptible to flood damage.
All these point to the need for resilience building measures, particularly to protect crucial infrastructure like electrical power -- one of the first casualties during a natural disaster. For example, when Hurricane Sandy struck the US East Coast in 2012, about 2,427 utility poles were toppled or broken, reportedly shutting off power to more than 8.5 million households. Back home, when Cyclone Wardah hit Chennai in December 2015, power supply was disrupted in the city and its neighbouring districts of Kancheepuram and Tiruvallur. Reports said thousands of concrete poles just collapsed and reportedly 32,000 poles had to be replaced in the three districts. Government officials were even quoted as saying that the estimated loss from uprooted poles alone was about Rs 65 crore. Inability of electricity poles (also called utility poles) to withstand strong winds contributes significantly to the disruption of power supply during such natural occurrences.
So how can critical infrastructure like electricity poles be saved during a disaster like a cyclone? One way could be to use better-suited material.
Ensuring power supply during natural contingencies
When typhoon Rammasun hit Guangdong in China, more than 70,000 concrete and metal poles collapsed. Earlier, in the aftermath of the massive Chuetsu earthquake in Japan in 2004, about 3,400 utility poles supporting communication cables were broken or toppled.
A post-event assessment revealed that many of the damaged poles were concrete. Concrete poles are comparatively difficult to repair or replace because of their weight and dependence on heavy machinery to install them. Besides, concrete has low tensile strength and often requires the use of materials like steel for reinforcement. When moisture seeps in through cracks in the concrete, the steel reinforcement rusts leading to further deterioration of the concrete pole.
There have been other instances of concrete and metal poles being completely destroyed by natural forces. In tornadoes that ripped through Florida in the late 90s for example, even 100-foot spun concrete transmission poles tested to withstand 250 mph winds, toppled. Ice storms such as the 1998 North American Ice Storm caused over a 1,000 steel towers to collapse under the accumulated weight of the ice. Some of these incidents led to the continued use of wood as a preferred material for utility poles. But environmental concerns emerged due to the use of certain chemicals for treatment of the wooden poles. Additionally, wooden poles are also vulnerable to natural disasters - in the earlier mentioned ice storm, over 30,000 wooden poles were found to have collapsed in addition to the steel ones. In the last few years, research has been conducted into the use of various other materials for utility poles even as wood, steel and concrete remained popular choices. But while all of them have their advantages, they also come with distinct disadvantages.
Concrete, for example, is strong, fire resistant and termite/rot proof, but has as previously mentioned, other disadvantages. Galvanized steel offers similar advantages as concrete, while also being lighter. However, it is also expensive, energy intensive to make, and hazardous since it conducts electricity. Wood, traditionally a popular material for utility poles, is also prone to decay and termite attacks, besides having low resistance to fire when unprotected.
All these factors have led to the development of new materials such as fibre reinforced polymer (FRP), which have proved to offer durability even during high intensity typhoons. For example, in the Rammasun typhoon mentioned earlier, a group of FRP utility poles were found to stand firm even when exposed to strong winds. These poles are made of a special kind of high-strength, high-flexibility polyurethane (PU) composite material called ‘Elastolit®’ developed by BASF. The poles have a strength that is easily 10 times greater than their weight and are only 250 kg, making them easy to transport and install them virtually anywhere. They are more durable and resilient than concrete poles, can withstand severe weather conditions and can also be optimized for specific conditions.
As in the case of Guangdong in China, replacing concrete poles with these FRP poles in areas facing high exposure to natural disasters in India has the potential to reduce the disruption caused to power supply during such events. To know more about BASF’s initiatives in this regard, click here.
This article was produced by the Scroll marketing team on behalf of BASF and not by the Scroll editorial team.