Transformers a risk to keeping the power on

We depend on electricity in our daily lives and for that power we rely on transformers. But they are also potential weak links in the grid. If one fails the entire network is rendered vulnerable. If a power surge occurs across the network, knocking out a number of transformers, the electrical grid could be crippled for months, even years.
Transformers are the critical links between the generation, distribution and transmission networks within the electrical grid. A major transformer failure can wreak havoc, causing power shortages or outages affecting millions of homes and businesses and costing many millions of pounds.
In June 2007 a transformer fire at Krümmel nuclear power station in Germany caused it and another nuclear plant at Brunsbüttel to be shut down. The resulting repairs put Krümmel – the largest reactor of its kind in the world – out of action for two years. Days after the plant was restarted in June 2009 further transformer problems forced it to be shut down again, creating power shortages across Hamburg. Following that, Vattenfall, the plant’s owner, decided to replace two of Krümmel’s important transformers, causing another lengthy shutdown.

Global shortages
The problem is that these transformer units are big, expensive to build and largely custom made. A recent surge in demand has pushed back delivery times, meaning that if a transformer fails it can take three years before a replacement is delivered.
The number of new transformers built around the world each year is less than 100 and manufacturers are weighed down by orders from India, China, Latin America and the Middle East, where new electrical grids are being built to cope with the booming demand for power. Shortages in the supply of copper, a vital component in the manufacture of transformers, have caused further delays and the cost to spiral.
“The situation has become so bad that in a bid to avoid protracted outage times some energy generators and utilities have bought hedges on the raw materials needed to manufacture transformers, and also on production slots for new transformers. These production hedges are even being traded now,” says Gary Stevens, Managing Director of GnoSys UK, a power industry risk consultancy.
The UK and other countries have sophisticated arrangements to ensure there is spare capacity within the system, so the power will stay on even if a major transformer fails. But this puts enormous pressure on the remaining network, which could lead to supply disruptions. 
Utility companies in these countries face tough choices between patching up their existing networks and investing in expensive new equipment. In order to meet government targets on greenhouse gas emissions cuts, companies will increasingly have to invest in new low-carbon or renewable energy networks.
Although they monitor their network so they know what demands they can place on its various elements, their ageing infrastructure means the probability of their equipment failing is uncertain. So-called ‘cascade failures’ where other parts of the system go down, whether by coincidence or because of the increased pressure, mean the weakened grid could buckle under the stress, causing blackouts. Infrastructure risk is an issue highlighted in Lloyd’s recent 360 Risk Insight report “Globalization and the risks for business.”

Nightmare prospect
The risk that a huge electromagnetic pulse (EMP) could knock out not one, but a string of transformers across the electricity network, crippling the system, is a nightmare prospect that is preoccupying governments. 
One source of such a powerful EMP is a terrorist attack using a nuclear bomb. “The electromagnetic pulse generated by a high altitude nuclear explosion is one of a small number of threats that can hold our society at risk of catastrophic consequences,” the US’s Critical National Infrastructures Commission stated in a 2008 report. “Damage to or loss of these components could leave significant parts of the electrical infrastructure out of service for periods measured in months to a year or more.”
The lack of readily available replacements “represents a glaring weakness in our survival and recovery to the extent these transformers are vulnerable,” the Commission concludes.
But it is not only extremists who pose a threat. The famous 1859 geomagnetic storm, the Carrington Event, was set off by a powerful solar flare that created an enormous electric charge that hit Earth. If it were to be repeated today it could cause between $1 trillion and $2 trillion of damage to our hi-tech infrastructure, said a study by the U.S. National Academy of Sciences. Depending on the scale of the damage, it could take four to 10 years to fully recover from the storm. This risk of geomagnetic storms is heightened by the fact that we are now entering a period of increased solar activity as we move towards the next Solar Maximum , expected in late 2012 or early 2013.