Assessing the accuracy of electricity production forecasts in developing countries
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DOI: 10.1016/j.ijforecast.2019.04.009
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- Makridakis, Spyros & Hibon, Michele, 2000. "The M3-Competition: results, conclusions and implications," International Journal of Forecasting, Elsevier, vol. 16(4), pages 451-476.
- Joseph, Kelli L., 2010. "The politics of power: Electricity reform in India," Energy Policy, Elsevier, vol. 38(1), pages 503-511, January.
- Peter R. Winters, 1960. "Forecasting Sales by Exponentially Weighted Moving Averages," Management Science, INFORMS, vol. 6(3), pages 324-342, April.
- Pao, Hsiao-Tien, 2009. "Forecast of electricity consumption and economic growth in Taiwan by state space modeling," Energy, Elsevier, vol. 34(11), pages 1779-1791.
- Ozturk, Ilhan, 2010. "A literature survey on energy-growth nexus," Energy Policy, Elsevier, vol. 38(1), pages 340-349, January.
- Catherine Wolfram & Orie Shelef & Paul Gertler, 2012.
"How Will Energy Demand Develop in the Developing World?,"
Journal of Economic Perspectives, American Economic Association, vol. 26(1), pages 119-138, Winter.
- Catherine Wolfram & Orie Shelef & Paul J. Gertler, 2012. "How Will Energy Demand Develop in the Developing World?," NBER Working Papers 17747, National Bureau of Economic Research, Inc.
- Robert C. Feenstra & Robert Inklaar & Marcel P. Timmer, 2015.
"The Next Generation of the Penn World Table,"
American Economic Review, American Economic Association, vol. 105(10), pages 3150-3182, October.
- Robert C. Feenstra & Robert Inklaar & Marcel Timmer, 2013. "The Next Generation of the Penn World Table," NBER Working Papers 19255, National Bureau of Economic Research, Inc.
- Perron, Pierre & Vogelsang, Timothy J., "undated". "Level Shifts and Purchasing Power Parity," Instructional Stata datasets for econometrics levshift, Boston College Department of Economics.
- Pablo Gluzmann & Demian Panigo, 2015. "Global search regression: A new automatic model-selection technique for cross-section, time-series, and panel-data regressions," Stata Journal, StataCorp LP, vol. 15(2), pages 325-349, June.
- Abdel-Aal, R.E. & Al-Garni, A.Z. & Al-Nassar, Y.N., 1997. "Modelling and forecasting monthly electric energy consumption in eastern Saudi Arabia using abductive networks," Energy, Elsevier, vol. 22(9), pages 911-921.
- Stephan B. Bruns, Christian Gross and David I. Stern, 2014.
"Is There Really Granger Causality Between Energy Use and Output?,"
The Energy Journal, International Association for Energy Economics, vol. 0(Number 4).
- Stephan B. Bruns & Christian Gross & David I. Stern, 2014. "Is There Really Granger Causality between Energy Use and Output?," The Energy Journal, , vol. 35(4), pages 101-134, October.
- Stephan B. Bruns & Christian Gross & David I. Stern, 2013. "Is There Really Granger Causality Between Energy Use and Output?," Crawford School Research Papers 1307, Crawford School of Public Policy, The Australian National University.
- Bruns, Stephan B. & Gross, Christian & Stern, David I., 2013. "Is There Really Granger Causality Between Energy Use and Output?," FCN Working Papers 11/2013, E.ON Energy Research Center, Future Energy Consumer Needs and Behavior (FCN).
- Holtedahl, Pernille & Joutz, Frederick L., 2004. "Residential electricity demand in Taiwan," Energy Economics, Elsevier, vol. 26(2), pages 201-224, March.
- Baltagi, Badi H. & Bresson, Georges & Pirotte, Alain, 2002. "Comparison of forecast performance for homogeneous, heterogeneous and shrinkage estimators: Some empirical evidence from US electricity and natural-gas consumption," Economics Letters, Elsevier, vol. 76(3), pages 375-382, August.
- James E. Payne, 2010. "Survey of the international evidence on the causal relationship between energy consumption and growth," Journal of Economic Studies, Emerald Group Publishing Limited, vol. 37(1), pages 53-95, January.
- Harris, John L. & Liu, Lon-Mu, 1993. "Dynamic structural analysis and forecasting of residential electricity consumption," International Journal of Forecasting, Elsevier, vol. 9(4), pages 437-455, December.
- Dilaver, Zafer & Hunt, Lester C, 2011.
"Modelling and forecasting Turkish residential electricity demand,"
Energy Policy, Elsevier, vol. 39(6), pages 3117-3127, June.
- Zafer Dilaver & Lester C Hunt, 2010. "Modelling and Forecasting Turkish Residential Electricity Demand," Surrey Energy Economics Centre (SEEC), School of Economics Discussion Papers (SEEDS) 131, Surrey Energy Economics Centre (SEEC), School of Economics, University of Surrey.
- Clemen, Robert T., 1989. "Combining forecasts: A review and annotated bibliography," International Journal of Forecasting, Elsevier, vol. 5(4), pages 559-583.
- Holt, Charles C., 2004. "Author's retrospective on 'Forecasting seasonals and trends by exponentially weighted moving averages'," International Journal of Forecasting, Elsevier, vol. 20(1), pages 11-13.
- Kwiatkowski, Denis & Phillips, Peter C. B. & Schmidt, Peter & Shin, Yongcheol, 1992.
"Testing the null hypothesis of stationarity against the alternative of a unit root : How sure are we that economic time series have a unit root?,"
Journal of Econometrics, Elsevier, vol. 54(1-3), pages 159-178.
- Kwiatkowski, D. & Phillips, P.C.B. & Schmidt, P., 1990. "Testing the Null Hypothesis of Stationarity Against the Alternative of Unit Root : How Sure are we that Economic Time Series have a Unit Root?," Papers 8905, Michigan State - Econometrics and Economic Theory.
- Denis Kwiatkowski & Peter C.B. Phillips & Peter Schmidt, 1991. "Testing the Null Hypothesis of Stationarity Against the Alternative of a Unit Root: How Sure Are We That Economic Time Series Have a Unit Root?," Cowles Foundation Discussion Papers 979, Cowles Foundation for Research in Economics, Yale University.
- Fisher-Vanden, Karen & Mansur, Erin T. & Wang, Qiong (Juliana), 2015.
"Electricity shortages and firm productivity: Evidence from China's industrial firms,"
Journal of Development Economics, Elsevier, vol. 114(C), pages 172-188.
- Karen Fisher-Vanden & Erin T. Mansur & Qiong (Juliana) Wang, 2012. "Costly Blackouts? Measuring Productivity and Environmental Effects of Electricity Shortages," NBER Working Papers 17741, National Bureau of Economic Research, Inc.
- Inglesi, Roula, 2010. "Aggregate electricity demand in South Africa: Conditional forecasts to 2030," Applied Energy, Elsevier, vol. 87(1), pages 197-204, January.
- Diebold, Francis X & Mariano, Roberto S, 2002.
"Comparing Predictive Accuracy,"
Journal of Business & Economic Statistics, American Statistical Association, vol. 20(1), pages 134-144, January.
- Diebold, Francis X & Mariano, Roberto S, 1995. "Comparing Predictive Accuracy," Journal of Business & Economic Statistics, American Statistical Association, vol. 13(3), pages 253-263, July.
- Francis X. Diebold & Roberto S. Mariano, 1994. "Comparing Predictive Accuracy," NBER Technical Working Papers 0169, National Bureau of Economic Research, Inc.
- Filippini, Massimo & Pachauri, Shonali, 2004.
"Elasticities of electricity demand in urban Indian households,"
Energy Policy, Elsevier, vol. 32(3), pages 429-436, February.
- Massimo Filippini & Shonali Pachauri, 2002. "Elasticities of Electricity Demand in Urban Indian Households," CEPE Working paper series 02-16, CEPE Center for Energy Policy and Economics, ETH Zurich.
- Yock Y. Chong & David F. Hendry, 1986. "Econometric Evaluation of Linear Macro-Economic Models," The Review of Economic Studies, Review of Economic Studies Ltd, vol. 53(4), pages 671-690.
- Narayan, Paresh Kumar & Smyth, Russell, 2005. "Electricity consumption, employment and real income in Australia evidence from multivariate Granger causality tests," Energy Policy, Elsevier, vol. 33(9), pages 1109-1116, June.
- Vogelsang, Timothy J & Perron, Pierre, 1998.
"Additional Tests for a Unit Root Allowing for a Break in the Trend Function at an Unknown Time,"
International Economic Review, Department of Economics, University of Pennsylvania and Osaka University Institute of Social and Economic Research Association, vol. 39(4), pages 1073-1100, November.
- Vogelsang, T.J. & Perron, P., 1994. "Additional Tests for a Unit Root Allowing for a Break in the Trend Function at an Unknown Time," Cahiers de recherche 9422, Universite de Montreal, Departement de sciences economiques.
- Vogelsang, T.J. & Perron, P., 1994. "Additional Tests for a Unit Root Allowing for a Break in the Trend Function at an Unknown Time," Cahiers de recherche 9422, Centre interuniversitaire de recherche en économie quantitative, CIREQ.
- Dikaios Tserkezos, E., 1992. "Forecasting residential electricity consumption in Greece using monthly and quarterly data," Energy Economics, Elsevier, vol. 14(3), pages 226-232, July.
- César Calderón & Luis Servén, 2004.
"The Effects of Infrastructure Development on Growth and Income Distribution,"
Working Papers Central Bank of Chile
270, Central Bank of Chile.
- César Calderón & Luis Servén, 2005. "The Effects of Infrastructure Development on Growth and Income Distribution," DEGIT Conference Papers c010_056, DEGIT, Dynamics, Economic Growth, and International Trade.
- Calderon, Cesar & Serven, Luis, 2004. "The effects of infrastructure development on growth and income distribution," Policy Research Working Paper Series 3400, The World Bank.
- Holt, Charles C., 2004. "Forecasting seasonals and trends by exponentially weighted moving averages," International Journal of Forecasting, Elsevier, vol. 20(1), pages 5-10.
- Abdel-Aal, R.E. & Al-Garni, A.Z., 1997. "Forecasting monthly electric energy consumption in eastern Saudi Arabia using univariate time-series analysis," Energy, Elsevier, vol. 22(11), pages 1059-1069.
- Martinez, Andrew B., 2015.
"How good are US government forecasts of the federal debt?,"
International Journal of Forecasting, Elsevier, vol. 31(2), pages 312-324.
- Andrew Martinez, 2014. "How Good Are U.S. Government Forecasts of the Federal Debt?," Economics Series Working Papers 727, University of Oxford, Department of Economics.
- Jamasb, Tooraj, 2006. "Between the state and market: Electricity sector reform in developing countries," Utilities Policy, Elsevier, vol. 14(1), pages 14-30, March.
- Suganthi, L. & Samuel, Anand A., 2012. "Energy models for demand forecasting—A review," Renewable and Sustainable Energy Reviews, Elsevier, vol. 16(2), pages 1223-1240.
- Ferguson, Ross & Wilkinson, William & Hill, Robert, 2000. "Electricity use and economic development," Energy Policy, Elsevier, vol. 28(13), pages 923-934, November.
- Elliott, Graham & Rothenberg, Thomas J & Stock, James H, 1996.
"Efficient Tests for an Autoregressive Unit Root,"
Econometrica, Econometric Society, vol. 64(4), pages 813-836, July.
- Graham Elliott & Thomas J. Rothenberg & James H. Stock, 1992. "Efficient Tests for an Autoregressive Unit Root," NBER Technical Working Papers 0130, National Bureau of Economic Research, Inc.
- Tom Doan, "undated". "GLSDETREND: RATS procedure to perform local to unity GLS detrending," Statistical Software Components RTS00077, Boston College Department of Economics.
- Tom Doan, "undated". "ERSTEST: RATS procedure to perform Elliott-Rothenberg-Stock unit root tests," Statistical Software Components RTS00066, Boston College Department of Economics.
- Mohamed, Zaid & Bodger, Pat, 2005. "Forecasting electricity consumption in New Zealand using economic and demographic variables," Energy, Elsevier, vol. 30(10), pages 1833-1843.
- El-Shazly, Alaa, 2013. "Electricity demand analysis and forecasting: A panel cointegration approach," Energy Economics, Elsevier, vol. 40(C), pages 251-258.
- Armstrong, J. Scott & Collopy, Fred, 1992. "Error measures for generalizing about forecasting methods: Empirical comparisons," International Journal of Forecasting, Elsevier, vol. 8(1), pages 69-80, June.
- Smith, Thomas B., 2004. "Electricity theft: a comparative analysis," Energy Policy, Elsevier, vol. 32(18), pages 2067-2076, December.
- Bianco, Vincenzo & Manca, Oronzio & Nardini, Sergio, 2009. "Electricity consumption forecasting in Italy using linear regression models," Energy, Elsevier, vol. 34(9), pages 1413-1421.
- Kim, Dukpa & Perron, Pierre, 2009.
"Unit root tests allowing for a break in the trend function at an unknown time under both the null and alternative hypotheses,"
Journal of Econometrics, Elsevier, vol. 148(1), pages 1-13, January.
- Mohitosh Kejriwal & Pierre Perron, 2006. "Unit Root Tests Allowing for a Break in the Trend Function at an Unknown Time Under Both the Null and Alternative Hypotheses," Boston University - Department of Economics - Working Papers Series WP2006-052, Boston University - Department of Economics.
- Bhattacharyya, Subhes C. & Timilsina, Govinda R., 2010. "Modelling energy demand of developing countries: Are the specific features adequately captured?," Energy Policy, Elsevier, vol. 38(4), pages 1979-1990, April.
- Perron, Pierre & Vogelsang, Timothy J, 1992.
"Nonstationarity and Level Shifts with an Application to Purchasing Power Parity,"
Journal of Business & Economic Statistics, American Statistical Association, vol. 10(3), pages 301-320, July.
- Vogelsang, T.I. & Perron, P., 1991. "Nonstationary and Level Shifts With An Application To Purchasing Power Parity," Papers 359, Princeton, Department of Economics - Econometric Research Program.
- Leitch, Gordon & Tanner, J Ernest, 1991. "Economic Forecast Evaluation: Profits versus the Conventional Error Measures," American Economic Review, American Economic Association, vol. 81(3), pages 580-590, June.
- Luis Serven & César Calderon, 2004. "The Effects of Infrastructure Development on Growth and income," Econometric Society 2004 Latin American Meetings 173, Econometric Society.
- Zachariadis, Theodoros, 2010. "Forecast of electricity consumption in Cyprus up to the year 2030: The potential impact of climate change," Energy Policy, Elsevier, vol. 38(2), pages 744-750, February.
- Ericsson, Neil R., 1992.
"Parameter constancy, mean square forecast errors, and measuring forecast performance: An exposition, extensions, and illustration,"
Journal of Policy Modeling, Elsevier, vol. 14(4), pages 465-495, August.
- Neil R. Ericsson, 1991. "Parameter constancy, mean square forecast errors, and measuring forecast performance: an exposition, extensions, and illustration," International Finance Discussion Papers 412, Board of Governors of the Federal Reserve System (U.S.).
- Michael P. Clements & David F. Hendry, 2001. "Forecasting Non-Stationary Economic Time Series," MIT Press Books, The MIT Press, edition 1, volume 1, number 0262531895, December.
- Saab, Samer & Badr, Elie & Nasr, George, 2001. "Univariate modeling and forecasting of energy consumption: the case of electricity in Lebanon," Energy, Elsevier, vol. 26(1), pages 1-14.
- Jevgenijs Steinbuks & Joeri de Wit & Artur Kochnakyan & Vivien Foster, 2017. "Forecasting Electricity Demand," World Bank Publications - Reports 26189, The World Bank Group.
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Keywords
Developing countries; Electricity demand forecasting; Time series econometric models; Forecast accuracy; Power generation investment planning;All these keywords.
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