15 August, 2022


The 70% Renewables Saga Again

By Kumar David

Prof. Kumar David

People were settling down to the belief that like Pavitra’s snake oil, the 70% electrical energy generation from renewables totem-pole that the President erected in his halcyon days immediately after his election had been quietly buried and forgotten. Unexpectedly this serenity was disturbed by a wakeup call last week from diehard aficionados of Aesop’s fables. My friend and top Canadian-Sri Lankan scientist Chandre Dharmawardana last week circulated, very widely, an email about how to increase the yield from the CEB’s major hydro projects wherein he made passing reference to the 70% story. That was not his issue but others on the list picked up on it and either disputed or supported it. This shows that even among professional scientists and a few engineers the myth persists. I have intervened in this farce before and this is the last time I intend to prove that a square does not has five sides nor explain that a leprechaun, a small size fairy-man, is supernatural.

Sitting as I am inside a strict quarantine room my facts may not all be up to date but they are good enough for my case today. The CEB Annual Report; unfortunately 2019 is the latest available online says that in that year gross-generation was 16.556 TWh (terra-watt-hours or billion-kilo-watt-hours, a kWh is commonly called a unit).

Say we use 16.56 TWh for this gross production hereafter.

Covid dampened the economy in 2020 and 2021 (no stats yet) but we also have the experiences of post-covid growth spikes in other countries. Hence it is reasonable to use an average 7% growth rate, which the CEB has used in the, past to prevail from 2019 to 2030. Using 7% growth for the eleven years from 2019 to 2030 (inclusive) the total annual electrical energy production needed in 2030 is 34.8 TWh. Forecasters are not soothsays and it could be higher or lower. (If it turns out to be much lower woe unto Sri Lanka because electricity usage is a reliable indicator of economic growth). Plans and projections must be updated regularly as circumstances change. Planners are familiar with this and call them ‘Rolling Plans’. If the economy nosedives due to debt-default, covid or economic mismanagement in the next three or four years, electricity demand will also plummet. The availability of money for everything, food and medicine included, leave aside new electrical plant, will be squeezed and governments may go out of the window. I will not contemplate this doomsday scenario here because that is a parallel universe. I will assume that normal growth (7% electricity growth is quotidian) will be sustained and that reasonable funding will be available for expansion of the electricity sector and funding will be made available for a robust renewables programme.

I now turn to a second point from the same (2019) CEB Annual Report which provides a pie-chart of generation breakdown by source. Here is what it says:-

* Major Hydro: 23.76% (3.93 TWh) in 2019. Hydro is subject to vagaries of the weather and in some years can decline up to 25% of expectation and in other years be plentiful.

* Non-conventional renewable (NCR) Mini Hydro: 6.35% (1.05 TWh). This too is subject to the rain gods.

* Wind+Solar+Biomass+Rooftop-solar: (W+S+B) group, added up in 2019 to 4.71% (0.78 TWh).

All renewables, Major Hydro, Mini Hydro and the (W+S+B) group add to 34.79% (5.76 TWh) of total generation. The other nearly 65.2% (16.56 – 5.76 = 10.80 TWh) was coal and oil fired electricity. This was in 2019.

Let us round the 2019 renewable total of 5.76 as 5.8 TWh (34.8% of total electrical energy). Observe that of this Mini Hydro (1.05) plus the (W+S+B) group (0.78) add to 1.83 (11% of total). Let’s round this to 1.8 TWh. To repeat, of the grand total of energy production 65.2% was from coal and oil thermal sources. You don’t need to bother with all these details. Keep only these two numbers in mind; all the renewables including Major Hydro added to 34.8% of total production in 2019 and its magnitude was 5.8 TWh. Excluding major hydro the renewals group was 11% that is 1.8 TWh.

Previously I estimated the production need in year 2030, if national economic development goes well at an averaged out growth rate of 7%, as 34.8 TWh. Am I an optimist in respect of mother Lanka? If you feel so you can reduce this figure by 10% or whatever you wish but I am sticking with it to prove my point. Seventy percent of 34.8 is 24.4 TWh. To attain the President’s target by 2030 we will have to increase our renewable sourced electrical energy from 5.8 TWh to 24.4 TWh! That is another 18.6 TWh. Since envisaged new major hydro will only add 0.35 TWh (see below) the other part the [mini hydro + (W+S+B)] group will have to provide the rest. That is expand from 1.8 TWh in 2019 to 18.25 TWh (18.6-0.35) in year 2030. This is why I asked whether as a child you enjoyed Aesop’s Fables?

And in the nearly three years since President Gotabaya floated his idea in late 2019 how much in renewable sources have we added to the generation mix? A quarantine room is not the best place to collect data, but I guess it’s about 0.6 TWh. But the government daydreams of adding another 18 TWh by 2030! I maintain that a total of 12 TWh annual total renewable source generated electrical energy is a healthy and optimistic target to aim for by year-2030. That is to say, add another 6.2 TWh on top of the existing 5.8 TWh instead of crazy notions of adding 18 TWh. Coal power is environmentally bad, no question. Let’s minimise it as soon as feasible but the last three are the operational words. OK let’s stop quarrelling about percentages; we can all agree that the share of renewable energy has to be increased. Let’s aim to get the renewable total to 12 TWh and take it from there after that. What if we get there before 2030 – great! If not let’s keep striving.

Another important matter is availability. Once you “use up” all your hydro sources, the best wind and the best solar sites, there’s no more to be had. This has already happened with major hydro; after Mahaveli there are only a few less significant plant. Broadlands and Umma Oya, between them just 0.35 TWh annually (compared to Victoria alone 0.78 GWh annually, and Norochcholi 1, 2 and 3 about 5 TWh annually) and a few miniscule ones left for the CEB to do. Renewables by their nature are energy limited and once you use them up that’s it.

Broadlands: 35 MW capacity, 0.125 TWh energy

The solar energy potential of Sri Lanka is greatly exaggerated in layman discussions. We do not have anything even remotely comparable to the insolation levels of the Atacama, the Gobi or Rajasthan. And we do not have enough land to spare due to competing needs – tea, paddy, villages, small towns and cities. We are an island of some 22 million souls in a 60,000 sq. km land. We can’t uproot the tea, chop down Singharaja or cover Minneriya with solar panels and damn the aquatic life beneath! These are the constraints within which we need to think. It’s not a gloomy picture but a challenging one. Let’s focus on 12 TWh for now.

The Atacama: Larger than Sri Lanka, cloudless, clear, arid, elevation 1400 ft.

God’s gift to the solar power engineer

Say you reach say X% (no matter 50 or 35 or whatever) renewable sourced electrical energy by Year-Y (no matter 2030 or 2040 or 2050 or whenever) using up the best known sources. Then as a percentage their share will decline in years thereafter as demand grows. Demand keeps growing but you have no more resources to add.  To repeat:  Renewables by their nature are energy limited and once you use them up that’s it. What we have to do then is look for new technologies such as off-shore wind, increase solar-cell efficiency, mini-fusion and if it becomes available and the public will have it, small safe nuclear power. None of this will come easy and will require effort and investment. I can’t see a one off-shore wind farm (except on an experimental scale) coming on stream by 2030. In 2010, the US Energy Information Agency said “offshore wind power is the most expensive energy generating technology being considered for large scale deployment” according to Wikipedia; but costs have been falling in the last 10 years. There are also maintenance problems out at sea and operational issues pertaining to stochastic sources – I did a bit of work on wind-power with the Royal Institute of Technology in Stockholm in the 1980s modelling the stochastic aspect. The UK, Germany, Denmark and Belgium are going strong with large off-shore projects because consumers are prepared to pay higher prices for clean electricity. In Sri Lanka this is something for the future when we are richer.

We will have to install Norochcholi Unit 4 to avert power shortages in – soon but that depends on economic growth as I previously said. The next big generator will have to be an LNG powered plant. But these two essential plants have been delayed or sabotaged by political scabs and commercial bandits who support this or that supplier on whose commissions they lean. LNG most certainly is not a renewable source; it emits carbon dioxide and leaks ethane. Yes it is cheaper and less polluting than coal. But what’s the use of wailing about all this until the brigands get their cut, or till competent and fearless technologists take control of the processes.

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Latest comments

  • 1

    The UK, Germany, Denmark and Belgium are going strong with large off-shore projects because consumers are prepared to pay higher prices for clean electricity
    That is not entirely true! Many of the working class people in those nations are not happy with having to pay more and more in the name of ‘going green’ when they are struggling to make ends meet.

  • 1

    Coal power is environmentally bad, no question
    Solar, wind and hydro power all create their own environmental problems

    • 1

      Nuclear power is relatively safe, doesn’t harm the environment as much as coal, and is not dependent on weather or insolation. We aren’t in an earthquake zone either. Those are the pros. The cons are the dismal state of CEB professional expertise, which can’t keep Norochcholai going without hiccups and clouds of pollution. What could CEB engineers not do to a nuclear power plant? Then there is public opinion, already trained to believe in things like death by 5G and poisonous milk powder. Perhaps foreign engineers could run the plant. But there is an easier way. Since the Indians are already running a few nuclear plants nearby, why not pay them 50% of the cost of one more, and run a cable across? No pollution, no protests. Only Sri Lankan political stupidity stands in the way.

      • 0

        A Nuclear power plant run by 79 IQ Sri Lankans – sounds great!
        What could possibly go wrong?
        Good to see Prof Kumar can write a decent, informative article.

  • 0

    Sorry, LNG plant is prone leak METHANE not ethane. Volume for volume it is far more environmentally harmful than CO2 though it sticks around in the atmosphere for a shorter period.

  • 0

    While the analysis of long term power generation requirement may be correct, what about roof-top PV penetration in the country? We have over 6 million roofs, amounting to over 75k hectares of roof space, mostly unutilized. How about a plan to use them with Solar Self-consumption which burdens grid only 20%, which will ease the burden of an immediate grid upgrade? Many countries have adopted this concept and even moving forward with VPP concept. Both these methods, proven in other countries, will help Sri Lanka to achieve 70% goal from renewable energy by 2030, sustainably and cost effectively. Any thoughts on the matter and productive criticism will be appreciated.

    • 0

      If you have a rooftop panel, it doesn’t work at night or on rainy days. So the options are:
      1. Power cuts on rainy days,
      2. Pay for and keep a normal power plant on standby for rainy days.
      Rather defeats the purpose, doesn’t it?

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