National Energy Balance Report of Sri Lanka, How accurate is it?

By Dr. Janaka Ratnasiri | Published: 2:00 AM Feb 25 2021
FT National Energy  Balance Report of Sri Lanka, How accurate is it?

By Dr. Janaka Ratnasiri

President Gotabaya Rajapaksa’s ‘Vistas of Prosperity and Splendour’ Policy Framework, adopted as the National Policy Framework, has spelled clearly that at least 80% of the overall energy consumed in the country should come from renewable energy (RE) sources. Overall energy means energy consumed in all sectors – power, transport, industries, agriculture, construction, commercial and households, which are obtained from all sources of energy including imported fuels such as coal and petroleum oil and gas as well as indigenous sources such as hydro power, biomass and other renewable sources (ORE), wind and solar power plants. 

Sustainable Energy Authority of Sri Lanka 

The Sustainable Energy Authority of Sri Lanka (SEASL) is mandated by Act No. 35 of 2007 to maintain records of supply and consumption of energy in different sectors and publish a National Energy Balance Report (NEBR) annually. It has wide powers to regulate the entire RE industry. It has powers to demand data on all activities and sales related to all energy matters from institutions, companies and individuals while carrying out surveys. The Sub-articles of Article 41 describe these as shown below.

41. The Board shall be responsible for promoting security and reliability and ensuring cost effectiveness of energy delivery within Sri Lanka, and for that purpose:

(a) examine the energy sector performance, review and integrate institutional and sub-sectoral plans,conduct policy analysis, review compliance with national energy policy and strategies and make policy recommendations to the Ministry on the energy sector in general, and more specifically on RE resources and energy efficiency;

(b) conduct surveys and investigations, collect and compile data in collaboration with the Department of Census and Statistics, publish NEB reports and other documents providing information relating to the energy sector in general,and more specifically to energy resources,conversion, supply, utilization, conservation and economics;

(c) identify and analyse policy measures and recommend to the Ministry and other relevant agencies, specific policy measures  pertaining to fiscal incentives and disincentives, including pricing policies, taxation and institutional arrangements;

(d) obtain information relating to energy resources,research, reserves, conversion facilities and conversion levels, storage facilities and storage levels, transmission and distribution systems, sales,customers, costs, prices, income from sales, losses,employees and development plans of any institution, company or individual engaged in the business of energy or having jurisdiction over resources that possess an energy value; and

(e) inspect and obtain information about potential or existing energy supply facilities and their utilisation and consumption”.

Energy Supply in 2017

The NEBR gives the quantities of fuels supplied and consumed in various sectors both in original units and also in equivalent common energy unit of Giga-Joule (GJ). The original data are expressed in units of kilo tonnes (kt) for coal, biomass and oil and GWhs for hydro and other RE sources. The former is converted into equivalent amounts in GJ after multiplying the fuel mass by its net calorific value (NCV), in respect of each fuel. The RE outputs (other than biomass) given in GWh are converted into GJ by estimating the heat content of fuel consumed in a thermal power plant with efficiency 36% when generating an equivalent amount of energy. 

According to the NEBR 2017, the latest available, fossil fuels imported comprised 5,375 kt of petroleum oil and LPG with energy content of 232.2 PJ (43.9%) and 2,156 kt of coal with energy content of 56.9 PJ (10.8%) as well as energy generated from RE sources comprising 30.08 GWh of major hydro with equivalent energy content of 30.9 PJ (5.8%), 1.65 GWh of other RE (ORE) sources with equivalent 16.2 PJ (3.1%) and 11,810 kt of biomass with energy content of 192.9 PJ (36.6%). Thus, the total RE share in overall energy in 2017 was 45.4%. This is shown graphically in Fig. 1.

Energy consumption in 2017

Of the imported fuels, petroleum products dominate and the break-down of its consumption is given in Fig. 2. Nearly 2/3rd of all oil consumption is in the transport sector. Hence, any attempt to shift from fossil fuels to renewables in the overall energy mix will have to address how to meet transport needs from renewables. Of the indigenous sources, dominant fuel is the biomass consumed in households and industries. Roughly, 1/3rd of biomass is consumed in industries and the balance in households for cooking. 

The Energy Flow Diagram

The Energy Diagram shows the flow of energy from supply sources to the consumers after going through various conversion processes. The width of the lines indicates roughly the relevant quantities. This is shown in Fig. 3 in respect of 2003.

Necessity to present NEBS Report to the Parliament

The Article 42 of the Act also requires the SLSEA to “submit annually to the Minister, a report on the performance of energy sector in Sri Lanka during the preceding year and the Minister shall table such report in Parliament for its consideration”. However, the latest available report is in respect of 2017. Currently the SLSEA website is not accessible. An inquiry made to the SLSEA did not bring any response.

The Energy Balance Report

The NEBR is a national document serving as the key source of energy data, but it has many shortcomings making its accuracy questionable. Some of these shortcomings are listed below.

1. Out of the above sources of energy, only the data on fossil fuels are reliable as they are commercially traded, while data on biomass consumption are only rough estimates and the NEBR gives only the consumption data without identifying the sources or the methodology of making the estimates. Hence, the validity of these data is questionable.

2. There is an issue with the major hydro and other renewables including solar photo-voltaic (PV) systems and wind energy systems in converting their output expressed in GWh into a common unit of giga-Joule (GJ). The SLSEA estimates the energy content of oil consumed in a thermal power plant having an efficiency of 36% generating the same amount of GWh generated from a renewable source as its equivalence in GJ. On the other hand, the international practice recommended both by UN agencies and International Energy Agency is to use the direct equivalent of GWh and GJ which is 1 GWh = 3,600 GJ, as 1 J is the same as 1 Ws. The use of oil equivalent conversion factor inflates the hydro and other RE contribution by a factor of 2.79. 

3. The methodology adopted by NEBR in the conversion of oil consumed in power plants originally expressed in litres into kilograms which is necessary to compute their heat content is flawed. For all types of fuels including naphtha, diesel, fuel oil and residual oil, NEBR assumes 1 kg/litre as the density which is not the case. The densities of these fuels are 0.85 kg/l for diesel, 0.95 kg/l for heavy oil and 0.69 kg/l for naphtha. Hence, using 1 kg/l as density for all these fuels invalidates the accuracy of the NEBR data significantly. 

4. The NEBR gives the details of fuel consumption only in respect of electricity generation in thermal power plants. It does not give details of diesel and gasoline consumed in the transport sector in their original units of litres. Hence, the accuracy of NEBR data on the fuel consumed in the road, rail and air transport given in kilotonnes could not be verified. Since the report is prepared by the Ministry of Power and Energy, it shows bias towards the power sector. 

5. Another shortcoming of NEBR data is the omission of solar thermal contribution in estimating the RE supply component. Many households use solar flat plate collectors to obtain hot water for bathing and washing, while industries and hotels use them for preheating water that is fed into boilers. Assuming households and industries in Sri Lanka have jointly installed 1 million sq.m. of solar collectors up to date, their output will amount to about 700 MW, comparable to what is generated from a solar PV park solar. 

6. In converting mass values of different fuels into their energy values, a knowledge of their net calorific values (NCV) is necessary. The writer belies that the NCV of every consignment of fuels imported is measured at the laboratories of CPC Storage Terminal and some are even published; eg. NCV data for coal are published by CEB. However, no effort is made by SLSEA to utilise these data in their computations but instead uses the same set of data from its inception. 

7. The data on energy consumption do not appear to be complete. Energy consumed in commercial establishments and in households are lumped together and shown as a single data set. Though a significant amount of fuel is used in the operation of agricultural machinery including harvesters and water pumps, these are not shown separately. Similarly, quantities of fuel consumed in the gemming industry and construction industry are not shown separately. If the fuels for these applications are obtained from road-side fuel outlets, they are probably categorised under transport.  A mechanism has to be introduced to record the supply of fuel into cans for use in non-transport activities separately, indicating the purpose. 

8.  Sri Lanka has a fishing fleet of about 40,000 motorized boats operating both in coastal and deep sea as well as in internal waters, according to Fisheries Statistics 2018 of the Ministry of Fisheries. Fuel is supplied to them from dispensers installed at about 25 major fisheries harbours located around the coast. However, there is no record of fuel consumed by these boats annually, either in the NEBR or anywhere else, which should be a substantial amount.  


If the RE component in the overall energy mix is to be determined accurately to verify whether it complies with the President’s target of achieving 80% by 2030, it is essential that the SLSEA pays more attention to removing the above-mentioned shortcomings, to improve its accuracy. The challenge is to raise the present RE share of 44.4% to 80% by 2030.

Dr. Janaka Ratnasiri served as the Chief Technical Adviser to the Ministry of Environment (1993-2000). He also served as a Consultant on Natural Gas to the Petroleum Resources Development Secretariat, developing a Road Map for the Utilisation of Natural Gas in Sri Lanka in 2013/14 and developing the National Policy on Natural Gas in 2017/18.  

By Dr. Janaka Ratnasiri | Published: 2:00 AM Feb 25 2021

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