By Dr. Janaka Ratnasiri
The Sunday Morning on 29 November 2020 carried an article written by a staff writer, posing the question “why sun-drenched SL lags behind in solar power?” An attempt is made in this write up to answer some of the questions raised by the writer and also to clarify some points.
Is Sri Lanka sun-drenched?
First, a clarification of the title is necessary. The map of solar irradiation accompanying the article tells the story that Sri Lanka is not sun-drenched, as claimed in the title. It shows high levels of solar irradiation only along the coastal belt in the Dry Zone, with some penetration in the South and North regions. In the Wet Zone, the sky is overcast and cloudy on most days of the year and not the best for solar energy utilisation. However, the low irradiation could be compensated by using additional photovoltaic (PV) panels over the optimum.
There are two methods of utilising solar radiation for electricity generation. One is to use solar PV panels which convert solar radiation directly into electricity, with an efficiency of about 16-22%, depending on its type. The other is to use solar radiation to generate thermal energy to heat a fluid-producing vapour at high pressure, which in turn could drive a turbine to generate electricity. However, such systems are technically and economically feasible in regions of very high irradiation such as deserts. They have the advantage of being able to use solar energy even after the sun has set, while with PV panels, the usage is limited to daytime.
Sri Lanka’s position in per capita electricity consumption
The article says, “Sri Lanka’s per capita energy (electricity) consumption is 636 kWh, one of the highest in the South Asian region”. Though this may be true for South Asia, it is close to the bottom end when compared with other Asian countries. Sri Lanka is only above a few countries like Cambodia (423 kWh), Myanmar (313 kWh), Bangladesh (379 kWh), and Nepal (207 kWh), based on 2017/2018 data found in a 2020 ADB publication on “Key Indicators for Asia and the Pacific”.
The rest of the countries in Asia are way ahead of Sri Lanka. Of particular interest is Taiwan, a country with similar land area, geography, and population as Sri Lanka’s, which has a per capita electricity consumption of 11,614 kWh in 2018. Most of the other countries have values between 2,000 and 10,000 kWh per capita. Sri Lanka has a long way to go to come close to these countries in power consumption.
Sri Lanka’s highest demand for electricity is during 6 p.m.-10 p.m. for consumption in households for lighting and perhaps watching television. The low demand during daytime reflects the poor industrialisation in the country. The countries in the Far East and Southeast Asia, having high per capita consumption of electricity, are referred to as newly industrialised countries. This industrialisation has helped them to increase their per capita electricity consumption. Though Sri Lanka’s government after government over the last several decades have endeavoured to attract foreign direct investments (FDI), for various reasons, Sri Lanka has not been able to attract FDIs as much as what other countries in the region have.
Storage of solar power
One inherent characteristic of solar panels is their availability as a source of energy only during daytime. It peaks at noon and its strength declines with the increasing solar angle. Hence, the energy that a solar panel generates during the day is equivalent to what it generates at noon for about five hours. The PV installations already in use in Sri Lanka show that their plant factor to be about 20%, which means they are available only for 4.8 hours a day. On the other hand, a thermal power plant can supply energy during the entire 24 hours a day, but annually, it may drop to about 70-80% due to shut down for maintenance.
In order to make use of solar energy generated during the day during the nighttime, it is necessary to store electricity by suitable means. If the system is connected to the grid, solar energy generated during the day can be fed to the grid and at nighttime, the grid provides electricity to the consumer. Hence, there is no need for a separate storage facility. If a domestic installation such as a rooftop solar panel system needs to be used off-grid as an independent system, it is necessary to have batteries for storing the electricity generated during the day. However, if large solar power systems are to be used at utility scale, a different approach is necessary, though the use of large size batteries is also possible, which are expensive and have limited life time of about five years. Their disposal also causes an environmental issue, unless economic recycling facilities are available.
One method is to make use of existing hydropower reservoirs by saving water that would have been used for generating an equivalent amount of energy generated by solar panels during the day, and using the water saved during nighttime. This does not require any additional expenditure on building extra facilities. Another is to build pump-storage facilities comprising two sets of reservoirs at two elevations connected via a penstock with a generator/pump system at the bottom. Any surplus energy generated during the day from solar panels is made use of to pump water from the lower reservoir to the upper reservoir. At nighttime, the pumped water is allowed to flow down the penstock, driving the pump in the reverse mode to generate electricity. In the West, such pump-storage systems have been used for many decades for peaking purposes. One good example is the system installed at Niagara Falls.
Another method available is to feed the solar panel output to a set of electrolyzers, which are available commercially, to generate hydrogen. The hydrogen is stored and fed to a bank of fuel cells to generate electricity in the form of direct current (DC) and later inverted to AC (alternating current). After filtering out harmonics, this steady output is fed to the grid as and when necessary, day or night, using stored hydrogen. The water generated by the fuel cells as a byproduct, after refining, could be fed back to the electrolyzers, thus minimising the demand for freshwater. This system is more economical and environmentally friendly than using batteries for storage. Even the surplus wind capacity which cannot be connected directly to the grid could be operated as stand-alone systems, with the output converted to DC and fed to electrolyzers.
CEB’s follow-up of Cabinet decisions
A previous regime launched a programme named “Soorya Bala Sangramaya” (SBS) to be implemented in four phases, with a view to accelerate the utilisation of solar power in the country. Under Phase I, it aimed to generate 1 GW from one million solar rooftops, each with a capacity of 1 kW. Phase II of the programme relates to building 150 solar power plants, each with a capacity of 1 MW to be built by the private sector on the build-own-operate (BOO) basis in two stages of 60 and 90 plants, each of a 1 MW capacity. The entire cost including land acquisition and extension of the grid as well as getting clearances has to be met by the investor.
Tenders were called by the Ceylon Electricity Board (CEB) in 2017 for building initially 60 plants of 1 MW capacity and in 2018 for building another 90 plants of 1 MW capacity. However, the outcome of these tenders providing information on the number of bidders, prices offered, and the number selected for building the power plants has not been announced. Also, the outcome of these tenders providing information on the number of bidders, prices offered, and the number selected for building the power plants has not been made public. (https://asia.unlockingsolarcapital.com/news/2017/4/10/sri-lanka-seeks-bids-for-60-mw-of-large-scale-pv).
In 2020, another tender was floated, inviting investors to build solar power plants with capacities in the range 3-10 MW, amounting to a total of 150 MW at specified locations where grid substations are available under Phase III of the SBS programme. (http://taiyangnews.info/markets/sri-lanka-awards-10-mw-pv-capacity/).
The CEB expects to build a total of 50 MW of capacity during this phase. The tender has specified an upper limit for bids amounting to 0.079 USD/kWh for accepting bids.
Govt.’s decisions to develop large solar systems
In 2017, the Cabinet took several decisions to build an aggregate of 1,000 MW of large solar power plants under Phase IV of the SBS programme, comprising a 800 MW solar park in Pooneryn, a 100 MW solar park in Siyambalanduwa, and a 100 MW solar system on Maduru Oya Reservoir, together with unspecified capacity to be installed on abandoned paddy fields in the Western and Sabaragamuwa Provinces and on government buildings, for which a sum of Rs. 300 million was allocated. According to CEB’s Long Term Generation Expansion Plan 2020-39, initial assessments and planning work for developing solar parks in Pooneryn and Siyambalanduwa have been initiated. The Pooneryn park will initially produce 250 MW of wind power and 150 MW of solar PV generation. These projects were reaffirmed by the Cabinet in 2019.
In addition, the Budget 2021 plans to add 1,000 MW in capacity through local investments within the period from 2021-2023 and instal 100,000 of 5 kW rated rooftop systems, adding 500 MW to the grid, through loan schemes. Furthermore, an increase of RE capacity to 1,000 MW by the expeditious implementation of both offshore wind and floating solar power plants exceeding 100 MW was also planned. This is reconfirmation of decisions taken in previous cabinet meetings and not new decisions. The problem has been that since the previous decisions were not implemented by the responsible parties on time, the impression has been created that no decisions were taken in the past for RE development.
Implementation of Soorya Bala Sangramaya
Though the Cabinet of Ministers since 2016 has been taking decisions to introduce RE projects, including solar power systems, at both domestic level and utility scale, their follow-up by the two implementing agencies – viz. Sri Lanka Sustainable Energy Authority (SLSEA) and CEB – has been rather slow, possibly due to divided responsibility. According to the SLSEA Act, any RE project needs the approval of the SLSEA before commencing any work.
Under the National Electricity Act No. 31 of 2013, any generation unit to be connected to the grid needs not only the approval of the CEB, but also needs to conform with the CEB’s Long Term Generation Expansion Plan. The Act also refers to accepting projects selected after calling for tenders except those recommended by the SLSEA. The misinterpretation of the Electricity Act has resulted in projects recommended by the SLSEA getting held up by the CEB.
According to a SLSEA report dated 27 March 2019, several RE projects submitted by investors that have received the approval of the SLSEA since 2016 have been held up as CEB has not agreed to sign the power purchase agreements with them, citing a section of the Electricity Act. These pending RE projects are shown in the accompanying table.
The main barrier appears to be the reluctance of the CEB to grant priority for developing RE projects compared to what it gives for developing coal power projects. It appears that all they are interested in is building more and more coal power plants, polluting both the local and global environment. In the CEB’s Long Term Generation Expansion Plan 2020-39, provision has been made to add only 900 MW of solar capacity up to 2030. This is despite the fact that the previous cabinet decisions had wanted about 2,000 MW of solar power added within a shorter time frame, comprising 1,000 MW of rooftop systems and 1,000 MW of utility systems.
Funding for solar power projects
The CEB also has not shown any interest in utilising funding available for the development of solar power systems offered by foreign sources. Under the International Solar Alliance, India has offered a $ 100 million credit line for the development of solar projects and has assigned a company in India to help Sri Lanka to build a solar park. This is a good opportunity to get one of the two planned solar parks built. Apparently, the CEB has not expressed any willingness to accept this offer.
Under the Paris Agreement, funding is available for developing countries to build RE projects that will save carbon emissions. However, it is necessary for the host institution to prepare a suitable project proposal and submit it to the Secretariat of the UN Framework Convention on Climate Change (UNFCCC) through the Ministry of Environment, which is the National Focal Point of UNFCCC, to seek the funding. The writer’s understanding is that neither the CEB nor the SLSEA has taken the trouble to prepare a proposal to seek funding for this purpose.
The CEB Act provides the CEB with powers to conduct research into matters affecting the generation, distribution, transmission, supply, and use of electricity (Article 12h). However, CEB’s annual reports do not refer to any research being done within the CEB, except undertaking testing of lamps. The students having the highest scores at the GCE Advanced Level examination get admitted to engineering courses and those who follow electrical engineering end up in institutions like the CEB. It is a pity that the CEB management does not make use of these talented graduates to undertake research to seek solutions to such problems, such as integrating RE systems into the grid, developing new storage systems, and providing other research and development support for RE systems, referred to in the said article.
Conclusion
The reason for Sri Lanka to lag behind other countries in harnessing its solar power potential appears to be the lack of interest shown by the CEB even to implement the many projects approved by the Cabinet. Even if they are interested, it is not seen. The Minister of Power needs to look into this issue urgently.
(The writer possesses a BSc (Hons) in Physics from the University of Ceylon and a PhD in Electrical Engineering from the University of Illinois, USA. He is a Fellow of the Institute of Physics, Sri Lanka. He has worked for 30 years as Research Officer in Applied Physics and Electronics at the Ceylon Institute of Scientific and Industrial Research [present Industrial Technology Institute]. He has served the Ministry of Environment for seven years as Senior Technical Advisor, handling environment-related matters in energy, transport, and industrial sectors. He has represented the country in many meetings of the UN Framework Convention on Climate Change during his tenure at the Ministry)
First, a clarification of the title is necessary. The map of solar irradiation accompanying the article tells the story that Sri Lanka is not sun-drenched, as claimed in the title. It shows high levels of solar irradiation only along the coastal belt in the Dry Zone, with some penetration in the South and North regions. In the Wet Zone, the sky is overcast and cloudy on most days of the year and not the best for solar energy utilisation. However, the low irradiation could be compensated by using additional photovoltaic (PV) panels over the optimum.
There are two methods of utilising solar radiation for electricity generation. One is to use solar PV panels which convert solar radiation directly into electricity, with an efficiency of about 16-22%, depending on its type. The other is to use solar radiation to generate thermal energy to heat a fluid-producing vapour at high pressure, which in turn could drive a turbine to generate electricity. However, such systems are technically and economically feasible in regions of very high irradiation such as deserts. They have the advantage of being able to use solar energy even after the sun has set, while with PV panels, the usage is limited to daytime.
Sri Lanka’s position in per capita electricity consumption
The article says, “Sri Lanka’s per capita energy (electricity) consumption is 636 kWh, one of the highest in the South Asian region”. Though this may be true for South Asia, it is close to the bottom end when compared with other Asian countries. Sri Lanka is only above a few countries like Cambodia (423 kWh), Myanmar (313 kWh), Bangladesh (379 kWh), and Nepal (207 kWh), based on 2017/2018 data found in a 2020 ADB publication on “Key Indicators for Asia and the Pacific”.
The rest of the countries in Asia are way ahead of Sri Lanka. Of particular interest is Taiwan, a country with similar land area, geography, and population as Sri Lanka’s, which has a per capita electricity consumption of 11,614 kWh in 2018. Most of the other countries have values between 2,000 and 10,000 kWh per capita. Sri Lanka has a long way to go to come close to these countries in power consumption.
Sri Lanka’s highest demand for electricity is during 6 p.m.-10 p.m. for consumption in households for lighting and perhaps watching television. The low demand during daytime reflects the poor industrialisation in the country. The countries in the Far East and Southeast Asia, having high per capita consumption of electricity, are referred to as newly industrialised countries. This industrialisation has helped them to increase their per capita electricity consumption. Though Sri Lanka’s government after government over the last several decades have endeavoured to attract foreign direct investments (FDI), for various reasons, Sri Lanka has not been able to attract FDIs as much as what other countries in the region have.
Storage of solar power
One inherent characteristic of solar panels is their availability as a source of energy only during daytime. It peaks at noon and its strength declines with the increasing solar angle. Hence, the energy that a solar panel generates during the day is equivalent to what it generates at noon for about five hours. The PV installations already in use in Sri Lanka show that their plant factor to be about 20%, which means they are available only for 4.8 hours a day. On the other hand, a thermal power plant can supply energy during the entire 24 hours a day, but annually, it may drop to about 70-80% due to shut down for maintenance.
In order to make use of solar energy generated during the day during the nighttime, it is necessary to store electricity by suitable means. If the system is connected to the grid, solar energy generated during the day can be fed to the grid and at nighttime, the grid provides electricity to the consumer. Hence, there is no need for a separate storage facility. If a domestic installation such as a rooftop solar panel system needs to be used off-grid as an independent system, it is necessary to have batteries for storing the electricity generated during the day. However, if large solar power systems are to be used at utility scale, a different approach is necessary, though the use of large size batteries is also possible, which are expensive and have limited life time of about five years. Their disposal also causes an environmental issue, unless economic recycling facilities are available.
One method is to make use of existing hydropower reservoirs by saving water that would have been used for generating an equivalent amount of energy generated by solar panels during the day, and using the water saved during nighttime. This does not require any additional expenditure on building extra facilities. Another is to build pump-storage facilities comprising two sets of reservoirs at two elevations connected via a penstock with a generator/pump system at the bottom. Any surplus energy generated during the day from solar panels is made use of to pump water from the lower reservoir to the upper reservoir. At nighttime, the pumped water is allowed to flow down the penstock, driving the pump in the reverse mode to generate electricity. In the West, such pump-storage systems have been used for many decades for peaking purposes. One good example is the system installed at Niagara Falls.
Another method available is to feed the solar panel output to a set of electrolyzers, which are available commercially, to generate hydrogen. The hydrogen is stored and fed to a bank of fuel cells to generate electricity in the form of direct current (DC) and later inverted to AC (alternating current). After filtering out harmonics, this steady output is fed to the grid as and when necessary, day or night, using stored hydrogen. The water generated by the fuel cells as a byproduct, after refining, could be fed back to the electrolyzers, thus minimising the demand for freshwater. This system is more economical and environmentally friendly than using batteries for storage. Even the surplus wind capacity which cannot be connected directly to the grid could be operated as stand-alone systems, with the output converted to DC and fed to electrolyzers.
CEB’s follow-up of Cabinet decisions
A previous regime launched a programme named “Soorya Bala Sangramaya” (SBS) to be implemented in four phases, with a view to accelerate the utilisation of solar power in the country. Under Phase I, it aimed to generate 1 GW from one million solar rooftops, each with a capacity of 1 kW. Phase II of the programme relates to building 150 solar power plants, each with a capacity of 1 MW to be built by the private sector on the build-own-operate (BOO) basis in two stages of 60 and 90 plants, each of a 1 MW capacity. The entire cost including land acquisition and extension of the grid as well as getting clearances has to be met by the investor.
Tenders were called by the Ceylon Electricity Board (CEB) in 2017 for building initially 60 plants of 1 MW capacity and in 2018 for building another 90 plants of 1 MW capacity. However, the outcome of these tenders providing information on the number of bidders, prices offered, and the number selected for building the power plants has not been announced. Also, the outcome of these tenders providing information on the number of bidders, prices offered, and the number selected for building the power plants has not been made public. (https://asia.unlockingsolarcapital.com/news/2017/4/10/sri-lanka-seeks-bids-for-60-mw-of-large-scale-pv).
In 2020, another tender was floated, inviting investors to build solar power plants with capacities in the range 3-10 MW, amounting to a total of 150 MW at specified locations where grid substations are available under Phase III of the SBS programme. (http://taiyangnews.info/markets/sri-lanka-awards-10-mw-pv-capacity/).
The CEB expects to build a total of 50 MW of capacity during this phase. The tender has specified an upper limit for bids amounting to 0.079 USD/kWh for accepting bids.
Govt.’s decisions to develop large solar systems
In 2017, the Cabinet took several decisions to build an aggregate of 1,000 MW of large solar power plants under Phase IV of the SBS programme, comprising a 800 MW solar park in Pooneryn, a 100 MW solar park in Siyambalanduwa, and a 100 MW solar system on Maduru Oya Reservoir, together with unspecified capacity to be installed on abandoned paddy fields in the Western and Sabaragamuwa Provinces and on government buildings, for which a sum of Rs. 300 million was allocated. According to CEB’s Long Term Generation Expansion Plan 2020-39, initial assessments and planning work for developing solar parks in Pooneryn and Siyambalanduwa have been initiated. The Pooneryn park will initially produce 250 MW of wind power and 150 MW of solar PV generation. These projects were reaffirmed by the Cabinet in 2019.
In addition, the Budget 2021 plans to add 1,000 MW in capacity through local investments within the period from 2021-2023 and instal 100,000 of 5 kW rated rooftop systems, adding 500 MW to the grid, through loan schemes. Furthermore, an increase of RE capacity to 1,000 MW by the expeditious implementation of both offshore wind and floating solar power plants exceeding 100 MW was also planned. This is reconfirmation of decisions taken in previous cabinet meetings and not new decisions. The problem has been that since the previous decisions were not implemented by the responsible parties on time, the impression has been created that no decisions were taken in the past for RE development.
Implementation of Soorya Bala Sangramaya
Though the Cabinet of Ministers since 2016 has been taking decisions to introduce RE projects, including solar power systems, at both domestic level and utility scale, their follow-up by the two implementing agencies – viz. Sri Lanka Sustainable Energy Authority (SLSEA) and CEB – has been rather slow, possibly due to divided responsibility. According to the SLSEA Act, any RE project needs the approval of the SLSEA before commencing any work.
Under the National Electricity Act No. 31 of 2013, any generation unit to be connected to the grid needs not only the approval of the CEB, but also needs to conform with the CEB’s Long Term Generation Expansion Plan. The Act also refers to accepting projects selected after calling for tenders except those recommended by the SLSEA. The misinterpretation of the Electricity Act has resulted in projects recommended by the SLSEA getting held up by the CEB.
According to a SLSEA report dated 27 March 2019, several RE projects submitted by investors that have received the approval of the SLSEA since 2016 have been held up as CEB has not agreed to sign the power purchase agreements with them, citing a section of the Electricity Act. These pending RE projects are shown in the accompanying table.
| Energy Source | Number | Capacity MW | Plant Factor % | Energy GWh/y |
| Mini-Hydro | 247 | 264 | 40 | 925 |
| Solar PV | 668 | 2028 | 20 | 3,553 |
| Wind Systems | 84 | 673 | 35 | 2,063 |
| Total | 999 | 2,965 | 6,541 |