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Yardstick Regulation of Electricity Distribution – Disentangling Short-run and Long-run Inefficiencies

Subal C. Kumbhakar and Gudbrand Lien

Year: 2017
Volume: Volume 38
Number: Number 5
DOI: https://doi.org/10.5547/01956574.38.5.skum
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Abstract:
In this paper we estimate the short-run, long-run and overall efficiency of Norwegian electricity distribution companies for the period 2000-2013 controlling for both noise and company effects. Short-run inefficiency is the part of inefficiency that is allowed to adjust freely over time for each company, but long-run (persistent) inefficiency remains constant over time, although it is allowed to vary across companies. For robustness check we also consider two additional models in which either company effects are not controlled or these are treated as inefficiency. The production technology is represented by a translog input distance function in all three models. We find that technical change and returns to scale are quite robust across the models. However, the efficiency scores across the three models we consider are not correlated strongly. We conclude that the regulators and practitioners should take extra caution in using the proper model in practice, especially when the efficiency measures are used to reward/punish companies through incentives for better performance.



Disentangling Costs of Persistent and Transient Technical Inefficiency and Input Misallocation: The Case of Norwegian Electricity Distribution Firms

Subal C. Kumbhakar, Orjan Mydland, Andrew Musau, and Gudbrand Lien

Year: 2020
Volume: Volume 41
Number: Number 3
DOI: 10.5547/01956574.41.3.skum
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Abstract:
Numerous studies have focused on estimating technical inefficiency in electricity distribution firms. However, most of these studies did not distinguish between persistent and transient technical inefficiency. Furthermore, almost none of the studies estimated the cost of input misallocation arising from non-optimal use of inputs. One reason is that the cost function (input distance function) typically used in the literature does not allow for the separation of technical inefficiency and allocative inefficiency. In this study, we estimate both the persistent and transient components of technical inefficiency and input misallocation of Norwegian electricity distribution firms, using panel data from 2000 to 2016. Our modeling and estimation strategy is to use a system approach, consisting of the production function and the first-order conditions of cost minimization. Input misallocation for each pair of inputs is modeled via the first-order conditions of cost minimization. We also estimate the costs of each component of technical inefficiency and input misallocation by deriving the cost function for a multi-output separable production technology. Our modeling and estimation strategy handles endogeneity of inputs. Finally, we allow for inclusion of determinants of persistent and transient technical inefficiency. Our results show that the costs of input misallocation of Norwegian electricity distribution firms are non-negligible.



The Effect of Restructuring Electricity Distribution Systems on Firms’ Persistent and Transient Efficiency: The Case of Germany

Oleg Badunenko, Astrid Cullmann, Subal C. Kumbhakar, and Maria Nieswand

Year: 2021
Volume: Volume 42
Number: Number 4
DOI: 10.5547/01956574.42.4.obad
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Abstract:
We evaluate the efficiency of electricity distribution operators (DSOs) as providers of local public infrastructure. In particular, we consider two types of efficiency, i.e., short-term (transient) and long-term (persistent). We apply the recently developed four-component stochastic frontier model, which allows identifying determinants of the two types of efficiency, after controlling for firm heterogeneity and random noise, to a panel dataset of German DSOs observed during 2006�2012. Those DSOs operating in the eastern parts of Germany have undergone a profound restructuring after the reunification in 1990. We find that this was beneficial for their efficiency as they perform, on average, better in terms of persistent efficiency than DSOs in West Germany. Both eastern and western DSOs perform similarly well in terms of transient efficiency, which is expected as the sector is highly regulated. As such, we provide new insights on identifying the nature and sources of public infrastructure productive inefficiency, which is relevant for public policies.



Efficiency Measurement in Norwegian Electricity Distribution: A Generalized Four-Way-Error-Component Stochastic

Mike G. Tsionas and Subal C. Kumbhakar

Year: 2023
Volume: Volume 44
Number: Number 2
DOI: 10.5547/01956574.44.2.mtsi
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Abstract:
In this paper, we introduce a new model to estimate efficiency by generalizing the state-of-the-art panel stochastic frontier model, the salient feature of which is decomposition of inefficiency into a persistent and a transient component. The proposed model introduces an autoregressive process to allow for temporal dependence in transient inefficiency. Both firm heterogeneity and persistent inefficiency components are allowed to be correlated with some exogenous and endogenous covariates in the model. Our model solves the endogeneity problem and it also introduces determinants of both persistent and transient inefficiency. Since the transient component is autoregressive, the likelihood function is not available in closed form. To address this problem we use the Maximum Simulated Likelihood and (Simulated or Bayes) Generalized Method of Moments method to estimate the parameters and several other quantities of interest, including transient and persistent inefficiency. Since the model is dynamic and accommodates determinants of inefficiency, it is useful to production managers who wish to identify how much of their present inefficiency is affected by past inefficiency, as well as how and in what ways efficiency can be improved. We use Norwegian electricity distribution data to showcase an application of our model.



Endogenous Bad Outputs and Technical Inefficiency in U.S. Electric Utilities

Mike Tsionas and Subal C. Kumbhakar

Year: 2024
Volume: Volume 45
Number: Number 1
DOI: 10.5547/01956574.45.1.mtsi
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Abstract:
In this paper, we consider a simultaneous modeling of good and bad outputs. We use an input distance function (IDF) with endogenous inputs as well as endogenous bad outputs, which is novel in the literature. Moreover, we model input efficiency to depend on the production of bad outputs which allows us to investigate whether emissions of pollutants (bad outputs) are related to technological performance (technical efficiency). We also model production of each bad output with a spatial structure separately, each depending on production of good outputs, inputs and other exogenous variables. These bad output production functions allow us to estimate both direct and indirect effects of good output on the production of bad outputs, which may be of special interest because they show the cost (to the society) in terms of releasing pollutants to the environment in order to increase production of good outputs. We apply the new technique to a data set on U.S. electric utilities with four bad outputs, three inputs and two good outputs. We used a Bayesian technique to estimate the model which is a system consisting of the input distance function, reduced form equations for each input, dynamics of inefficiency and bad output production technology—separately for each. Empirically, bad outputs are found to affect inefficiency positively. Percentage increases in inefficiency due to a percentage increase in each bad output are found to vary from 0.225% to 0.42%. Energy prices are found to be positively related to inefficiency. From the spatial specifications of bad outputs, we find that the spillover effects of increasing production of good outputs account for the majority of the total effect, indicating that neighborhood effects are more important than own effects. This means, the neighboring utilities played a crucial role indicating "contagion" of practices.





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