Exercise 9: Energy balance

Transcription

1 Exercise 9: Energy balance PART 1: Understanding the energy balance Please choose and open one of the files 2013_BAL_COUNTRY.xls. This file is the IEA balance builder for the COUNTRY of your choice. The purpose of the IEA Balance Builder is to build a country energy balance following the IEA methodology starting from data in physical units. In this case, the file has been prefilled for your analysis. In the sheet Aggregated balance, you find a complete energy balance for the given country, for the year The goal of this introductory exercise is to understand the main concepts behind an energy balance and to become familiar with it. The series of questions below will guide you through an analysis of the balance. Supply 1. Is the country an energy producer? If so, of what products? Disaggregated balance worksheet. Look at the production (row 7) first for primary products. Secondary energy production appears in the transformation sector. Check positive numbers which show output. 2. What is the largest energy source in the country s energy mix? In Disaggregated balance worksheet check the Domestic supply row. In Aggregated balance worksheet check the TPES row. 3. Is the country overall self-sufficient? Why? Look in Aggregated balance worksheet. Calculated as production/tpes. Use the column Total of all energy sources to calculate. Less than 1 means the country is not self-sufficient and depends on imports. 4. Look for the values of TPES/population in 2000 and 2012 by selecting the country in the right menu at: Has it changed? TPES/population is a rough indicator of how much energy is consumed per person.

2 Transformation 5. What is the difference between a negative number and a positive number in the transformation sector? Negative numbers show an input to a transformation process and a positive numbers shows an output. 6. What are the sources of electricity in the country? Disaggregated balance worksheet. The sources of electricity will appear as a negative number under the different fuels in the transformation sector under the main activity and autoproducer electricity and CHP plants (row 17 to 20) 7. Focus on main activity electricity producers: how much energy is lost in the transformation process in the overall electricity generation? What share of the total input to electricity does it represent? Disaggregated balance worksheet. The losses appear in the column Total (column BP) as a negative number in row 17. To calculate the share you need to add all the input in the row 17 first to get the total input. 8. Bonus question: If the country has generation of electricity from coal or natural gas main activity producers, what is the specific efficiency of generation? (Use information of electricity generation by source at the bottom of the page; note that 1 GWh = ktoe). Look in Aggregated balance worksheet. The efficiency of the main activity producers for coal is calculated by taking the corresponding output in GWh in row 62 multiplied by to get ktoe and then divide by the input reported in row 12 Final consumption 9. What is the largest final consumption sector? Look in Aggregated balance worksheet. Check out the rows Industry, Transport, Other and Non-energy use to see which sector has the biggest number in Total (row P) 10. What is the share of oil products in road consumption? Look in Aggregated balance worksheet. Take the amount in cell F44 (which is the amount of oil products consumed in Road) and divide by P44 (which is the total amount consumed in Road).

3 PART 2: Building the energy balance Please open the file BalanceBuilder_Statisland.xls The purpose of the IEA Balance Builder is to build a country energy balance following the IEA methodology. This can be done either by filling by hand the Data in physical units and Conversion factors worksheets or by uploading data from the IEA data questionnaires. Whenever data need to be adjusted, it is good practice to adjust the corresponding questionnaire and re-upload it. You are presented with a partially filled balance builder, follow the instructions below to complete the data. Note that yellow cells indicate errors (as explained in the Main Menu worksheet). Before starting, open the Data in physical units worksheet. You will note the following issues: there is an arithmetic error for other bituminous coal anthracite has data on the Data in physical units worksheet but no data on the Disaggregated balance worksheet, due to missing net calorific values in the Conversion factors worksheet. Now do the following: 1. Please adjust the coal questionnaire STATISLAND_Coal.xls for 2013 according to the following: a. Other bituminous coal: consumption in Industry Sector - Non-metallic minerals was accidentally left out. It should be 7666 kt. b. Table 4 : Update the following net calorific values: Anthracite: kj/kg for production, kj/kg for Imports, kj/kg for exports, kj/kg for Used in main activity plants, kj/kg for Used in industry and kj/kg for For other uses. 2. Once you are done with the above changes you can upload the coal questionnaire. 3. Check the Balance Builder to make sure that all the errors were corrected.

4 General balance question: 4. Look at the nuclear and hydro columns in the Data in physical units worksheet, numbers are reported in electricity output not in production and transformation, why? Looking at nuclear and hydro in the aggregated balance worksheet we find numbers in production; how are they calculated? What is the implied efficiency? Physical Units Data In hydro plants, the energy of the falling water is used directly to produce electricity. It cannot be used elsewhere. Therefore, the most logical measure of the energy production is the electricity output from the turbines. For nuclear plants, the heat from the reactors is the primary energy form selected by the IEA because the heat can either be used to generate electricity (the usual case) or can be used directly. Aggregated Balance Data To estimate an input to electricity plants that do not use fossil fuels the following conventions are used when using the Physical Energy Content Method. For hydro plants, 100% efficiency is assumed. This is because there is no benefit in calculating the energy of the falling water, as unlike heat, it has no other useful application. So the data in physical units are multiplied by to convert from GWh to ktoe. For nuclear, when data on the heat input to the turbines is unavailable, then it can be estimated by assuming a turbine efficiency of 33% (this is based on the European average). Any heat that is produced that is used directly should have been measured. So, the electricity output in physical units is multiplied by and then divided by The heat output used directly is converted from TJ to ktoe by multiplying by

5 Bonus question: 5. Please open the file Statisland_bonus_question.xls. This is a copy of the aggregated balance worksheet in BalanceBuilder_Statisland. Let s assume that electricity production of Main activity producer electricity plants from Coal stopped completely and was replaced by an equal amount of Hydro electricity generation. Note that production of coal would decrease by the same amount that used to go as input to Main activity producer electricity plants. Before making any change to the energy balance please calculate the percentage of renewables in both the TPES and in total electricity output. Then, change the relevant parts of the energy balance and recalculate calculate the new percentage of renewables in both the TPES and in total electricity output by filling the table below. Hint: 1 GWh=0.086 ktoe Renewables share in total electricity output in TPES Before change 12.4% 6.4% After change 49.8% 14.4% Changes to be made in energy balance: For coal, Mainelec=0 and Production decreases by the amount that used to go to Mainelec. TPES is adjusted accordingly. Coal electricity output in GWh becomes equal to zero. For Hydro, electricity output in GWh will increase by the same amount that was previously generated from coal. The input to Mainelec will have to be recalculated and production and TPES adjusted. The total column also changes accordingly...