Addis Fortune (Addis Ababa)
Omer Redi
1 June 2009
(Page 2 of 3)
This is one of the biggest tunnel projects. Cleaning the tunnel; removing the railing and ventilation system, along with qualitative consolidating of electromechanical system and civil works are expected to be completed at the end of July. Immediately after that, we will start filling the tunnel and generate power according to the schedule.
Q: Still on Gilgel Gibe II, which you expect to be the solution to the current situation, now the remaining part of the actual physical works are the about 200m of construction of the tunnel and other tunnel related works. When these are finalized, there is cleaning. Then, there are three stages of testing: dry test, wet test and commercial test, how long will all this take in total?
I think first of all, there is something we should not forget; the highest voltage (400Kv) and the longest transmission line (230Km) is also going to be commissioned. This is the first of its type in Ethiopia. The transmission is completed. It also includes opticfiber communication wire for telecom purposes and two of the biggest substations in the country - Sebeta II and Gibe End - are completed.
Now dry test is going on simultaneously at the power plant and the substation along with the remaining works because we want to save time. The wet test starts when the water is full in the tunnel and the good thing about it is even if it is somehow disrupted, we test it by loading [power] and supplying to the system; that is the advantage. The wet test and the commissioning test, even if in terms of time we stop and start, we can do that by synchronizing to the system. That means by supplying power to the system.
Q: So you are planning to undertake wet test and commercial test at the same time?
We do it simultaneously. We test it by actually feeding the power to the system and that is also what we mean by loading. Even we want the big industries to be on because we have to test it with the highest load in the system.
Q: How long does the cleaning take?
We are trying to make it shorter and expect this to be finalized in about two months. Let us not forget it is a more than 25Km long tunnel which is so unpleasant for human beings. You can't survive 200m in the tunnel without air and people, in fact, have died because of humidity and high temperature. For that reason, we have been using ventilation with safety standards and very standard technological facilities that we have to take out now.
Q: What elements does cleaning include?
Cleaning the more than 25Km long tunnel includes removing the railing, a very complicated ventilation system, and equipment that helps the Tunnel Bowering Machine for lighting the tunnel. It is after the tunnel that we see consolidated grouting and the tunnel should be solidified by the civil work. This is also called curing time, once you do the concrete wall, you need civil work of cement and concrete, so it is a drying and curing standard engineering time. And there are some works at the intake part before opening the tunnel.
Q: The dry test does not need water because you simply load power (voltage) to the generators from another sources to check its capacity, proper operation and sustainability. So I expect you have started this test alongside other works long before. How long have you been doing that test and what elements do the dry system include?
It is an every day job. In the past months, we were doing it on the turbines system, the control system, the protection system and the SCADA system. It includes the turbine (turbo machine) system and its functionality, generator, other hydraulic and electromechanical systems which have measurement, control, protection and safety systems. And the SCADA system, where you can control the whole plant using a computer, and where you can see the plant synchronized with the national grid, is also part of this test. This is a high-tech system that we stimulate by installing and feeding some false data to test the whole system. It is a matter of high evaluation on how stable the plant is with a very high standard quality that requires professional work.
Q: Once the dry test and cleaning are finalized, you go on to the wet test along with the commercial test, which is actually commissioning the power, is that right?
Yes, we clean and test the tunnel first. This includes testing the pressure, the water flow, the intake structure, the penstocks (the two 1.2Km each long steel pipes) and the turbo machine system with water. After these works are completed, we will make sure the whole system is ready, by feeding and supplying power from zero to the maximum capacity, then after that the commercial test goes on.
Q: I am aware that what you referred to as an internationally accepted standard and procedure of testing power generation plants demands the three levels of tests to be undertaken one after the other. It is only after these tests that the contractor will handover the project to you for actual commissioning. And of course, you test the plant for sometime before you release the performance guarantee bond. In total, it takes about six months. Now you are telling me that you are going to finalize the tests in about two months or so, while undergoing wet and commercial tests at the same time. I can understand the immense pressure you have been under due to the power crisis and how quick you want this project to be commissioned. But won't that be risky? Will the project contractor be willing to hand you over the project without going through the normal practice?
No! Not that way! You do not have to isolate some part of the system. You can do some separate tests but you synchronize them to the system. I am sure EEPCo's capacity and experience in the past 60 years in the power system is competitive and the contractor has to rely on our capacity on the particular matter. So I'm sure we know our business and we will do it to the best interest of the public. Since it is team work, we will achieve our timing and keep the one year warranty with the contractor. After that, we can stop the plant and check everything before taking out its liability. But we will not undermine the safety rules because of the pressure.
Q: Let me take you back to the blackout issue. There used to be a line dedicated for businesses engaged in export trades. There are reports that you have stopped that. Along with the current situation of the power shedding arrangement, which is at least every other day', that indicates the shortage of power supply and the level of water at the dams has reached a critical level. Considering the worst case scenario, for example, if the expected rain turns out to be negative, how long will you be able to supply power with the current amount of water?
With regard to the consumer grouping, it is based on the economic and social impact of the power outage. We have classified consumer groups. In terms of the industrial aspect, we have heavy industry consumers who have a dedicated line or one mixed with the other domestic or commercial consumers. We have export industries which have a dedicated line or one mixed up with the other from domestic or commercial consumers. When it is the social aspect, we have very sensitive consumers, like hospitals, schools, clinics, as well as water supply and telecom facilities.
The significant power demand is from the industry with commercial and domestic sectors. Thus, the saving is also from these sectors. Those heavy industries are warned to plan their maintenance in this time of shortage to mitigate the impact with the possible demand side management.
Most of them are to be appreciated for obeying the notice, and they are doing major inspection and maintenance works. Some of them are preparing their emergency supply for this period. They will be able to survive by doing their critical activities. Export industries are classified under a clearly committed market. They have been given power, whether through a line dedicated to them or in between consumers; since they are the major aspects of the Ethiopian economy they are given priority.
But as citizens of this nation, sometimes they should share the burden by using their own internal capacity. Since they have the financial capacity, they have to be part of the solutions by using their resources.
About the water level, on our part, we are very vigilant not to let the volume go below the lowest acceptable level. Though we have been successful in maintaining that level of water, the peak hour is still challenging us. Nevertheless, our optimistic plan is to keep to the same situation up to July. It also depends on consumers' behaviour, like in workshops, garages, and bakeries. They have to shift to stay with today's consumption for tomorrow, and it also requires consumers' behaviours to live with discipline for short periods and hope for a bright future. This is the fact of life in the whole continent, even in the world.
Be the first to Write a Comment!
AllAfrica aggregates and indexes content from over 125 African news organizations, plus more than 200 other sources, who are responsible for their own reporting and views. Articles and commentaries that identify allAfrica.com as the publisher are produced or commissioned by AllAfrica.
