Sustainable Pathway to Sustainable Power



In the tenth episode of the SLEN Podcast, Eng. Suran Fernando speaks with the Head of CEB Long Term Planning, Eng. Lakshitha Weerasinghe about “Power Generation Strategy of the Country”.


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Eng. Suran Fernando :

You are listening to IESL SLEN Podcast, featuring a wide range of conversations on diverse engineering and non-engineering sectors of national importance. I am Eng. Suran Fernando, and today, for our 10th podcast, we have a special guest. Today, our discussion is on the power generation strategy of the country which is a hot topic discussed and argued in many engineering circles now-a-days. For that discussion we have Eng. Lakshitha Weerasinghe, who is the Head of CEB Long Term Planning. Let me warmly welcome Eng. Lakshitha Weerasinghe for today’s discussion.

Eng. Lakshitha Weerasinghe :

Thank you for considering me and inviting me for this podcast. I hope I would be able to do justice in the next 15 to 20 minutes to come.

Eng. Suran:

There is a lot of discussion in the society these days about generating electricity using renewable energy sources. Judging by certain criticism in the society on the main electricity supplier, Ceylon Electricity Board, it appears that CEB is not holding this same view on the role of Renewable Energy. As the head of CEB’s long term planning branch, what are your views on relying more and more on renewable energy sources to meet our future electricity requirements?

Eng. Lakshitha :

That is a good question. in fact, we also hold the same view as those in the society that we should gradually transition into a greener, cleaner future and gradually abandon fossil fuels. it is very clear that the entire world is moving in this same direction. and unlike during any other period in the past, we even see that the required associated grid support infrastructure and enabling technologies also coming up for us to make this transition. That means we can certainly rely on renewable forms of energy to meet our future electrical requirements. As a result, we are fully in agreement with the general view in the society that the country should gradually relieve itself from the dependency on imported fossil fuels and go for indigenous renewable forms of energy. in fact, if you go by our recent long-term generation expansion plans, including the recent most draft long term generation expansion plan prepared for a 20-year period, starting from 2022-2041 also is clearly aiming at taking the country in that direction. For example, the latest draft long term generation plan had not identified any Coal-fired power plant after 2030. It had identified only a single new coal plant of 300MW size as compared to nine in the current pan that had received the approval of the Public Utilities Commission. We planned it that way despite coal being the cheapest source of a thermal generation because coal steam technology does not operationally complement the requirements of when running a system with a large proportion of variable renewable energy sources. So, it is clear we too are heading for the same goal, in the same direction.

Eng. Suran :

If that is the case, why is there some criticism about CEB? Some claim that CEB is reluctant to go to Renewables.

Eng. Lakshitha:

Well, I don’t think there is any reluctance on the part of CEB. The criticism I think is more about the strategy adopted by CEB in reaching carbon-neutrality and what is expected from us by others. You must understand that we have a responsibility to keep the lights on while also listening to multiple drivers of the society including the government. As a result, our strategy of reaching for this low carbon future, which is of course is based on years of experience we have in operating our power system and in seeing practical limitations in executing projects in the country, is different to what is obviously expected from us by the others. I think it is mainly to do with the speed that we see as optimal and practical as against what some others think than anything else.

Eng. Suran :

What is CEB strategy then? Can you explain to our audience? It is very important to know from the CEB itself as it is the main electrical utility provider in Sri Lanka.

Eng. Lakshitha :

Let me explain. In order to understand what should be the correct strategy and what should be the correct speed at which renewable sources are to be added onto the system, one must have a little basic understanding of how power systems actually work. As you all know, from the day we decided alternating current, or AC as the best choice to transmit and distribute electricity, we have inherited what is known as synchronous power grids with synchronous generators, running in synchronism supplying the customer demand. in such a grid, the supply of electrical power (measured often in MW) must be exactly equal to the demand for electrical power in real-time. if this supply and demand balance is not maintained, in real-time from megawatt to megawatt, that affects the system frequency. and the system frequency is maintained within a very narrow and tight band. For example, when frequency deviates just 3 Hz from the nominal of 50Hz, the power grid could collapse. And that too within seconds.

So what is that got to do with renewables? If we are to go with a very high proportion of renewables, we have to rely on Solar PV and wind technology to take us there. (You know that all our hydro potential has been already exploited). And we all know that solar and wind have varying and intermittent outputs unless we take corrective action. In conventional power systems, maintaining the supply-demand balance was not a big problem as the only things that were changing were on the demand side or on the customer side. The power system operators, you know, power system operators are the engineers who are at national grid control centres like our own System Control Centre at SJP and centrally operating and dispatching the grid-connected generators and they also operate the high voltage transmission network. So, those system operators adjust conventional generators they have at their control and match the demand. Sometimes this is called load following. But now they have an additional problem. In addition to the customers, even some of the generators they have are now changing. As a result, they now have customers who change their demand minute by minute and generators like wind and solar who too change their output minute by minute. So, now maintaining the supply-demand balance must be done by very few remaining conventional synchronous generating units, whose share should now gradually come down also to give way to renewables like solar and wind. So that is one problem.

Now I told you earlier that in synchronous power grids the supply-demand balance must be maintained MW to MW in real-time. Actually, system operators do not intervene to maintain this balance in seconds to a millisecond scale. It is taken care of by the stored kinetic energy in the generators, mainly. So when customers suddenly ask for more electrical power in the next second or start using less power than in the last second, it is the stored kinetic energy that gets converted to electrical power in the generators before the primemovers that are coupled to the generators (it can be turbines or engines) start giving the mechanical power back to the generators. That is the nature of synchronous power systems. When kinetic energy changes, the generator rotational speeds changes and generator speeds are directly related to the frequency of supply and as a result frequency changes. That means, when the mechanical inertia of all the generators is high, there is lot of kinetic energy and that kinetic energy can take care of sizeable supply-demand imbalances without causing a significant change to speeds or frequency. But when the mechanical inertia is low, there a higher chance to the speed is required to give the same kinetic energy, and as a result, frequency is affected. So when the conventional generators gradually give way to solar and wind, the mechanical inertia too becomes low and low. Both wind and solar technologies have power electronic interfaces and do not add any mechanical inertia. Sometimes you may think that there are these big wind turbines, when you see the rotating blades they add mechanical inertia, but they don’t. their interface is power electronics. Same with solar. So we expect the mechanical inertia of our future power system to get lower and lower, and that means a more and more unstable grid, and we have to take corrective action for that. As a result, CEB strategy to low carbon future also address such technical problems on its way or else we could inherit a cleaner greener grid but with blackouts or brownouts!

Eng. Suran :

So, you mean to say, that it is the technical problems that keep us from making the transition faster? That means CEB engineers have failed so far to give proper solutions to those problems. Isn’t that the case?

Eng. Lakshitha :

I am glad you phrased the question that way, in fact, lot of people think so, and my answer is definitely NOT. Technical problems have technical solutions. Engineering problems have engineering solutions. It is not the lack of solutions but it is other practical limitations in implementing such solutions and also certain very important OTHER strategic reasons that had compelled the CEB to propose its own pathway to the greener grid. You know, one must understand that it must not only the energy sources that must be sustainable, but our progression to renewable itself must be sustainable. It is those reasons that keep CEB too from taking the very rapid, near-overnight transition that a lot of people are advocating.

Eng. Suran :

Now, you are saying about some limitations other than the technical problems that you mentioned earlier. Can you please share with us what those are? Initially, you said it is the technical challenges that you are more concerned about.

Eng. Lakshitha :

Let me put it like this. There are three important considerations in deciding the optimum pathway the country must take to the green grid. It is very important for our country to have our own pathway, have our own strategies in going for the green grid. We must not merely follow what other countries are doing but must take our own strengths and weaknesses and national priorities into consideration and devise our own strategies to come up with the best pathway.

So, as I told you before, there are three considerations.

First, consideration, there are challenges that we have to overcome on the way. There are three such challenges in my opinion, … which I will explain later…. and mind you only one of those challenges is the technical challenge. Technical challenge is the smallest of the three challenges though many think it is the biggest. Many try to teach us technical solutions and fundamentals of power systems thinking our reluctance to go faster is in fear of such technical problems. But contrary, … though the technical challenge is also a grave concern, in comparison it is the smallest of the three.

So, facing such challenges is the first consideration in deciding our own path to a low carbon future.

The second consideration is that there are very important benefits also that is available for us to gain or reap DURING the journey to maximize renewables. Going for renewables is not only about REACHING a target by such and such a date.

We must make the country also benefit, …not only by merely reaching the goal… but also during the transition. There are a lot of benefits available, which we are likely to miss if we unduly rush, I will explain this later.

So that is considered number two, the benefits.

The third consideration is, there are very important corrections and adjustments that we definitely require to make during our journey. If we simply try to JUMP from today to a target on say 2030, we are most likely would not be able to make those corrections and adjustments on the way. I will try to explain very briefly but it’s quite impossible for me to explain everything in a short chat like this. You know, the world around us is changing very rapidly and there are very important new developments in the field of Renewable Energy that we see coming up. Very promising and very interesting. Even now we see clearly different directions leading to the same end result of an all-renewable future. There are different directions that we could take to go to the same end result. So, unless we are very careful and try to go rapidly, but in small steps, we will not be able to make these corrective actions and adjustments. So CEB’s approach is to go in small steps but rapidly.

You must understand that going for the all-renewable future is not only by installing N number of solar parks and X number of wind parks. A lot of people think so, mainly influenced by the commercial lobby. But we see a lot of other opportunities we as a country must take note of and try to adopt during this journey rather than simply putting up solar and wind farms.

Eng. Suran :

Can you please elaborate on the three considerations that you mentioned? If I get it right, I think they are, first the challenges, the second, the benefits and third, the adjustments. So, can we start from the challenges?

Eng. Lakshitha:

There are three challenges, technical financial and implementational. They are coupled to each other. For example, if we try to achieve say 70% of electricity generated by 2030 from renewables, as I told you earlier, we have to rely on solar and wind to takes us there. Both these technologies, particularly solar have low plant factors. That means, to get the same equivalent energy of a 300MW LNG fired power plant running at 70% plant factor from solar, we need about 1000MW of solar. This is a big problem. Solar generates a very high power capacity during a shorter period of the day to give the same energy. Now, our transmission network must be rated to transmit 1000MW instead of 300MW to evacuate power from the solar plant to get the same equivalent energy. To evacuate power from solar and wind zones right around the country, we now need a very high capacity 400kV backbone transmission line network, connecting our load centres with RE zones. Right now our backbone transmission line is 220kV. But in order to transmit these high power capacities, we cannot rely on 220kV. So you have to upgrade to 400kV.

This is both a financial challenge and an implementational challenge very difficult to achieve. As per the very preliminary estimates we have made, we will require an additional 1.7 billion USD to invest in transmission infrastructure. That is required before 2029 if we are to achieve our target in 2030. Again, we also need to maintain the supply-demand balance every second. But now solar brings in more power than required by customers in real-time. I hope you can visualize now. As per our simulations, if we are to achieve 70% of generation from solar and wind by 2030, that requires over 1000MW of batteries to be installed by that time to take the excess generation that is coming from the solar and wind during day time. Batteries are only emerging technologies. There was a lecture recently where it was told that the total installed batter capacity word-wide is less than 2000MW. But here, we too require 1000MW. Also, battery prices, though rapidly falling, are still high. As per present costs, batteries will also require about 2 billion USD within the period 2025 to 2029. So there is a big financial problem for the country. Unlike conventional thermal plants where the costs are spread over 25 years, initially, you have the cavity cost and thereafter the operational cost which is the fuel cost. It spreads over 25 years. But for solar and wind, they don’t need any fuel. So they generate electricity without any cost during the operational period. But for solar and wind, the cash outflows are mainly upfront. Can the country afford to do so, amidst the present forex problem? Well, I do not know.

The third and the biggest challenge is the IMPLEMENTATIONAL challenge. If we are to achieve 70% from RE by 2030, we need about 400MW of solar PV on average per year from next year onwards. If we realize only a half of that using solar parks, we need 2 – 100MW solar parks constructed every year from next year. Mind you, we do not have a single 100MW solar park in the country and to purchase land for the first 100MW solar park at Siyambanalduwa, the Sustainable authority is struggling since 2017. It is not their fault. That is how things happen in this country. In addition to solar, once in every two years, we need three Mannar wind park size wind parks developed in the country. With the sort of implementation difficulties in the country, is it possible? I will let the audience to answer that question. Merely raising a target alone will not make anything.

That is why when Engineers say that something is “yes possible” it must be possible both technically and practically. We are not scientists, or academics or visionaries, who have the liberty to state anything they foresee as possible. We are engineers and remember as I told you at the beginning, we have a responsibility to keep the lights on! That is why when we say something is possible, it has to be possible both technically and as well as practically.

Eng. Suran :

Looks that we came to the interesting part of the discussion but since we are running out of time, Eng. Lakshitha, can I ask you to quickly let us know the other two considerations, the benefits and third, the adjustments you think as required?

Eng. Lakshitha:

The journey to renewables must be made in such a way that it breeds local industry, local entrepreneurship also. Our country does not have a big market to support large industries like automobiles. But power sector is sizeable to support the growth of new players compared to other opportunities. We already see that Sri Lankan business enterprises that entered into mini-hydro industry and even wind industry now operates very successfully even overseas. Same with even certain companies that carried out EPC contracts for thermal power plants like our own Lanka Transformers Limited. They now even operate in Bangladesh. There are very successful local companies that have invested in wind power. We must make this journey in such a way that local players, new small players, or those who are already experienced to come and do the development of RE and thus get benefitted from the opportunity. To do so, we must go gradually big with a mixed model. But if we simply rush to a high target, you will soon see only big international companies coming and doing the development. It is only such big international players who can engage in developing 100MW, 200MW, 300MW and even 500MW size development and we Sri Lankans will miss the opportunity to develop the small-scale industrial players capable initially to engage in smaller sizes 1MW, 10MW scale. So we missed the opportunity of developing them. It is them who later on stepping on to 20MV, 100MV and go overseas and that is how the business develops in a country. If we rush unduly, we also would see these international companies coming and asking for dollar-denominated tariffs. To take a very careful note on this, if you unduly rush it is the only big players who can come and take the challenge and ask for dollar-denominated tariff. In such an eventuality, we would not only be able to develop our own business sector but also will have to pay electricity produced by our solar and wind resources back in dollars. Is it any different to generating from imported fossil fuels?

CEB plans had already offered very big opportunities to the solar and wind industry. For example, as per the draft CEB generation plan, we plan to add over 2000MW of solar by the end of 2029, which is five times what we have now. That itself is a massive opportunity to the local business sector.

I do not have time to let you know what adjustments are we need as it takes time. But let me summarize the CEBs pathway to a low carbon future in one statement.

We intend to go from the high carbon electricity (I may call it the brown grid. Right now even though I call it high carbon electricity, our CO2 in single KW electricity that we produce is only 0.55 Kg of CO2 which is quite low by the world standards. But let’s call it the brown grid.) So if we intend to go from this brown grid initiative our plan is to initially via a blue grid that uses LNG as a transition fuel, that is why I have told you at the beginning that we have stopped generating new coal power plants by 2030. So it will be mainly LNG as a transition fuel to the greener grid of the future. Our proposal is to do so via successive generation plans from brown to blue to green, but not just within one plan but in successive generation plans that we would prepare once in every two years. So that we can adjust to new developments and practical technical challenges on the way. Our plan is to make our grid zero carbon ready first before we make the jump.

But if we simply try to take a big jump (thinking it is very attractive to have such policies and slogans), without realizing the bigger picture, well your guess is good as mine.

Thank you. .

Eng. Suran :

Yes. Those are the views of Eng, Lakshitha Weerasinghe who is the Head of Long Term Planning at CEB. Let us conclude this fruitful discussion now. Thank you very much engineer Lakshitha Weerasinghe for spending your valuable time to share your ideas, opinion, your strategy on the CEB’s path towards Renewable Energy. We wish you all the success in your future endeavours.

Eng. Lakshitha:

Thank you once again for giving me the opportunity to brief IELS membership of the quite pertinent subject. And also I take this opportunity to wish you all good success on your future endeavours and the SLEN. Thank you.

Eng. Suran :

Yes. Those are the views of Eng, Lakshitha Weerasinghe who is the Head of Long This is engineer Suran Fernando from SLEN podcast. Have a nice day!

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