Friday, March 18, 2016

Power outage: Some posers to CEB

Opinion by Dr. Janaka Ratnasiri - Nawala
In a news item in the Financial Review of The Island of March 17, titled "No guarantee blackouts would not occur in future", the General Manager of CEB was reported to have said that "all three machines at the Norochcholai power plant had been stopped due to the power failure and it takes a few days for them to cool before starting again."


This is something unusual to Sri Lanka, because if one looks at the situation in other countries where blackouts have happened, there is no such waiting time for the tripped plants to cool down before restarting. Wikipedia lists all the major electricity blackouts that have occurred in the past, and there have been many blackouts world-wide - North America, South America, Europe, India and SE Asia, for a variety of reasons, affecting hundreds of millions of people particularly in Asia. But, there was one common factor. They were able to restore the service within 10-15 hours after disruption.

I believe in most of these places, coal power plants were supplying electricity to the grid, and once they tripped, they did not have to wait several days until the plants cooled down before restarting. A report titled "Technical Assessment of operation of coal and gas fired power plants" prepared by a consultancy firm for the UK Department of Energy and Climate Change in August 2014 has listed the start-up times for both these types of power plants under hot start (idling less than 8 hrs) and cold start (idling more than 48 hrs).

A gas-fired combined cycle hot plant will take less than 25 min. after starting for delivering full load while a hot coal plant will take about 90 min. On the other hand, when starting from cold, a gas plant will take about 3 hr sand a coal plant will take about 7 hrs, before delivering full load. In any of these cases, no mention was made for the necessity to wait until the plant cooled down before starting.

If this is the situation in Sri Lanka with coal plants, unlike in all other countries using coal power, what is the wisdom of planning to install many more coal plants here when alternative plants with no such restrictions and which are more flexible for load variations are available at competitive prices? We must remember that lightning strikes, the cause for many of the blackouts, cannot be avoided altogether, but mechanism should be there to restore the service with minimum delay when a lightning strike disrupts the system.

Would the General Manager of CEB kindly explain to the public the reason, with regard to the Puttalam coal plant, why CEB has to wait several days until the plant cools down before they could reconnect the load to it, when there is no such requirement in other countries under similar situations?

I wonder what all the professional bodies and chambers who were clamouring for coal power have to say about the present situation with regard to the coal power plant, which I believe would have caused billions of rupee economic loss to the country.

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