Investement appraisal in a deregulated electricity market

  • Barrie E. Murray

Student thesis: Doctoral ThesisDoctor of Philosophy


This thesis analyses the impact of deregulation on the theory and practice of investment decision making in the electricity sector and appraises the likely effects on its long term future inefficiency. Part I describes the market and its shortcomings in promoting an optimal generation margin and plant mix and in reducing prices through competition. A full size operational model is developed to simulate hour by hour operation of the market and analyse its features. A relationship is established between the SMP and plant mix and between the LOLP and plant margin and it is shown bow a theoretical optimum can be derived when the combined LOLP payments and the capital costs of additional generation reach a minimum. A comparison of prices against an idealised bulk supply tariff is used to show how energy prices have risen some 12% in excess of what might have occurred under the CEGB regime.
This part concludes with proposals to improve the marl<et and in particular advocates a new approach to encourage optimal capacity planning using lagrangian techniques to indicate needs without loss of data confidentiality. Part 2 demonstrates that the classical approach to generation investment appraisal is no longer valid and develops a new approach. It is shown how an individual generator can predict his utilisation and income to establish the worth of investment and demonstrates the validity of the operational model proposed. An empirical relationship is developed between profit and capacity and this is used to develop the theory to illustrate how companies interact. 1bree different economic models are developed to represent different market conditions and these are tested against the actual investment decisions since deregulation to demonstrate their appropriateness. It is shown that the current market mechanisms could lead to suboptimal investment. Part 3 discusses the essential role of transmission in enabling competition and reviews worldwide practices illustrating little consensus on charging for its use. Basic costing principles are described and a new model is developed to demonstrate bow a generator may strike supply agreements either side of an interconnector to influence prices so as to maximise his income. The optimal pricing strategy for the transmitter is also derived and consumer response is simulated .The concept of transmission uplift is developed and the operational model is extended to include transmission constraints and then used to establish monthly incremental transmission constraint cost functions. It is shown how these can be used to appraise investment options and optimally plan outages. Part 4 concludes by discussing the regulatory framework and its limitations in improving efficiency or encouraging the optimum levels of investment. The principal findings of the thesis are reviewed and potential market improvement are described. This part concludes with a discussion of alternative market structures and likely future developments.
Date of Award1996
Original languageEnglish


  • Investement appraisal
  • deregulated electricity market
  • power systerns
  • generation
  • transmission
  • energy markets
  • marginal pricing

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