Opinion
Does Minister Gammanpila contradict President on energy targets?
By CHANDRE DHARMAWARDANA
Energy Minister Udaya Gammanpila has told the Consultative Committee on Energy that Sri Lanka was “sitting on USD 267 billion worth of oil and gas hidden in the Mannar Basin”. Is the Minister abandoning the renewable energy targets of the President, and unwittingly planning to destroy the Palk Strait’s ecosystem (Rodriguez et al. 2007), and return to a future based on fossil fuels? Are we to breach the Paris accord, and spew pollution that the ADB costs at 7% lost GDP!
While the Minister dreams of under-sea oil and gas, the CEB and its apologists uphold coal and fossil fuels, while downplaying renewable energy prospects in Sri Lanka. Similarly, Professor Kumar David (KD), a Fellow of the Institute of Electrical Engineers, writes frequently on Energy policy and takes a pessimistic prognosis for renewable energy in Sri Lanka. KD agrees with the CEB plan to continue with coal and other fossil fuels for future decades. Specifically, KD claims that supplying even 70% of the “energy needed.” using renewable sources by 2030 is sheer fantasy.
However, identifying a problem is half-way to the solution. The Sunday Island (12-September-2021) carries yet another article by Prof. KD where he repeats his concerns. Let us use KD’s identification of the problems in renewable energy as a basis for further discussion.
1. Randomness and Unpredictability in Solar and Wind outputs
As KD puts it, “If wind or solar output falls quickly by a hefty amount, it is the same as the forced outage of a big unit like Victoria or Norochcholai, and the shock to the system is similar”.
Victoria is a 210 MW facility, while most solar installations are small rooftop installations. KD rightly targets the ADB installed 100 MW wind farm in Mannar, significantly in the path of migratory birds. Wind energy installations have unknown unpredictable and NON-LOCAL environmental effects. I am no fan of wind energy and oppose large wind installations!
Big lenders like the ADB go for big Wind or Solar plants, and fail to understand the need for “distributed power”. Instead of a large solar plant, producing 100 MW and occupying a huge area in one location, let it be small solar plants (e.g., 5-10 MW) distributed all over the island. So, when clouds cover Mannar, the sun may shine in Monaragala or Hambantota. Although the output of each solar plant may fluctuate, the SUM of the many many solar plants DISTRIBUTED over the island will average to a steadier power output – the central limit theorem!
The problem envisaged by Professor KD is created when the CEB and the ADB opt for a 100 MW wind-power plant, without setting up similar plants in several places that balance out freak fluctuations. Such balance is out as Lanka lacks contrasting sites that can support 100 MW solar or wind farms. In contrast, Lanka has sufficient potential in deploying FLOATING SOLAR PANELS at 5-10 mw level and should prioritise floating solar.
Cloud cover fluctuations occur at the scale of many minutes, whereas a crest of electrical energy from panels in Mannar, can combine with a trough of energy from panels in Monaragala in less than a thousandth of a second, because electricity travels effectively at the speed of light.
Optimally handling power fluctuations in distributed arrays is a mature subject. In Hawaii too, the erratic fluctuations in solar energy, due to changing cloud cover is a problem. According to Dave Renne of the US-National Renewable Energy Laboratory (NREL) in Colorado, the Hawaii Clean Energy Initiative set up a measurement system and data sourcing that enabled the NREL team “to set up a solar-monitoring network that simulates exactly how clouds would impact a large photovoltaic system”. While Hawaii can profit from the US satellite data available to one-second precision, neither the CEB nor the sustainable energy organisations in Sri Lanka have any such data capability. Such research shortcomings can only be overcome by setting up a power-research institute (PRI), where an interdisciplinary team of scientists and engineers will work on these frontier problems.
In the following I argue that Sri Lanka can use its unique Hydro-power reservoir system for storing solar power, generated during the day by shutting off some turbines and conserving the corresponding amount of water in the reservoir for later use. Batteries are NOT needed.
2. Poor Sunshine in Sri Lanka
Prof. KD says that Sri Lanka is “not the Gobi Desert, Atacama or the Australian outbacks”. Interestingly, the available sunshine data for Sri Lanka are largely from US satellites and from scientists at the NREL in Colorado. Dave Renne et al. of NREL notes that the tropical clouds and humidity are a drawback except in certain times of the year, and yet conclude that “the annual results for Sri Lanka range from 4.5 to 6.0 kWh/sq. meters/day (and that)..the study shows that ample resources exist throughout the year for virtually all locations in Sri Lanka and the Maldives for PV applications. So, the NREL experts are, in my view, in contradiction to Dr. Kumar David.
3. Saturation of Renewable Energy Sources
Apologists for fossil fuels claim that sources of renewable energy in Lanka are already “saturated”, while the demand for power is “ever growing”. According to them, there are no more rivers to dam, no good windy sites, and no readily available land for solar farms.
The Floating Solar Option
There are ample crown-owned water surfaces in Lanka for installing floating solar panels. The density of reservoirs (230 ha for every 100 sq. km of land area) in Sri Lanka is the highest in the world. Additionally, placing floating panels on reservoirs SAVES loss of water by evaporation, boosting hydro-power outputs and agricultural water by as much as 30%.
The floating panels reduce the sunlight falling on the water and curb algae, aquatic weeds, and aquatic oxygen depletion (c.f., Exley et al., Solar Energy, Volume 219, 2021). The use of even 20% surface coverage is environmentally beneficial and aquatic organisms thrive better.
The current population of 21.2m is expected to reach a plateau of 22m (plus or minus 3%) by 2039 and then decrease. Hence, we anticipate a maximum power demand of 44 Terawatt hours (TWh) per annum for Sri Lanka, if Lankan’s are to enjoy the same standard of living as in the EU, with a per capita power consumption of 2000 Kwh per annum. The present supply is 16.6TWh from the existing hydroelectric and fossil-fuel power stations. Rounding off the 44TWh upwards to 50TWh, as the maximum ceiling of power needed, we need to generate an ADDITIONAL 34TWh to satisfy Lanka’s power needs to reach EU life standards in 2039, when the population peaks.
According to Professor David “The output for a one square-kilometre site in Puttalam, the NCP, NP or Hambantota will be about 150 GWh per year” ((https://www.colombotelegraph.com/index.php/impediments-to-a-better-ceb/)
Hence, generating the additional 34TWh will need an area of about 22,666 ha. The area occupied by major lakes, rivers and reservoirs in Sri Lanka is 375,000 ha (c.f., Somasundaram et al 2020), with some 160,000 ha covered by reservoirs (tanks). That is, covering a mere 14% of the available reservoir surfaces with floating solar, is sufficient to achieve the EU standard of consumption of electricity at the peak of Sri Lanka’s population growth.
Prof. KD’s estimate of 150 GWh per sq. km of solar is based on the current photo-voltaics with an efficiency of about 10%. High end cells (e. g, used for space applications) already operate at 40- 50% and will become standard within a decade.
Unlike in 2009 when these ideas were first suggested (see https://dh-web.org/place.names/posts/dev-tech-2009.ppt) to officials of the Presidential Secretariat by the author, today an even stronger case exists for running a pilot project.
In conclusion, with solar cells at 10%-50% efficiency, a mere 14%-3% coverage of the available reservoir surfaces with floating solar panels would be sufficient to meet ALL of Sri Lanka’s future power needs, at a per capita consumption of 2000kWh per annum, even when the population peaks in 2039, assuring even an EU standard of living.