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Volatility-price relationships in power exchanges: A demand-supply analysis


  • Sandro Sapio


The evidence of volatility-price dependence observed in previous works (Karakatsani and Bunn 2004; Bottazzi, Sapio and Secchi 2005; Simonsen 2005) suggests that there is more to volatility than simply spikes. Volatility is found to be positively correlated with the lagged price level in settings where market power is likely to be particularly strong (UK on-peak sessions, the CalPX). Negative correlation is instead observed in markets considered to be fairly competitive, such as the NordPool. Prompted by these observations, this paper aims to understand whether volatility-price patterns can be mapped into different degrees of market competition, as the evidence seems to suggest. Price fluctuations are modelled as outcomes of dynamics in both sides of the market - demand and supply, which in turn respond to shocks to the underlying preference and technology fundamentals. Negative volatility-price dependence arises if the market dynamics is accounted for by common shocks which affect valuations uniformly. Positive dependence is related to the impact of asymmetric shocks. The paper shows that under certain conditions, these volatility-price patterns can be used to identify the exercise of market power. Identification is however ruled out if all shocks affect valuations uniformly.

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  • Sandro Sapio, 2008. "Volatility-price relationships in power exchanges: A demand-supply analysis," LEM Papers Series 2008/07, Laboratory of Economics and Management (LEM), Sant'Anna School of Advanced Studies, Pisa, Italy.
  • Handle: RePEc:ssa:lemwps:2008/07

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    1. Weron, R & Bierbrauer, M & Trück, S, 2004. "Modeling electricity prices: jump diffusion and regime switching," Physica A: Statistical Mechanics and its Applications, Elsevier, vol. 336(1), pages 39-48.
    2. Fabien A. Roques & William J. Nuttall & David M. Newbery & Richard de Neufville & Stephen Connors, 2006. "Nuclear Power: A Hedge against Uncertain Gas and Carbon Prices?," The Energy Journal, International Association for Energy Economics, vol. 0(Number 4), pages 1-24.
    3. Eduardo Schwartz & James E. Smith, 2000. "Short-Term Variations and Long-Term Dynamics in Commodity Prices," Management Science, INFORMS, vol. 46(7), pages 893-911, July.
    4. Frank A. Wolak & Robert H. Patrick, 2001. "The Impact of Market Rules and Market Structure on the Price Determination Process in the England and Wales Electricity Market," NBER Working Papers 8248, National Bureau of Economic Research, Inc.
    5. Apostolos Serletis & John Herbert, 2007. "The Message in North American Energy Prices," World Scientific Book Chapters,in: Quantitative And Empirical Analysis Of Energy Markets, chapter 13, pages 156-171 World Scientific Publishing Co. Pte. Ltd..
    6. Catherine D. Wolfram, 1999. "Measuring Duopoly Power in the British Electricity Spot Market," American Economic Review, American Economic Association, vol. 89(4), pages 805-826, September.
    7. Simonsen, Ingve, 2005. "Volatility of power markets," Physica A: Statistical Mechanics and its Applications, Elsevier, vol. 355(1), pages 10-20.
    8. Rafal Weron, 2005. "Market price of risk implied by Asian-style electricity options," Econometrics 0502003, EconWPA.
    9. von der Fehr, Nils-Henrik Morch & Harbord, David, 1993. "Spot Market Competition in the UK Electricity Industry," Economic Journal, Royal Economic Society, vol. 103(418), pages 531-546, May.
    10. Postali, Fernando A.S. & Picchetti, Paulo, 2006. "Geometric Brownian Motion and structural breaks in oil prices: A quantitative analysis," Energy Economics, Elsevier, vol. 28(4), pages 506-522, July.
    11. Worthington, Andrew & Kay-Spratley, Adam & Higgs, Helen, 2005. "Transmission of prices and price volatility in Australian electricity spot markets: a multivariate GARCH analysis," Energy Economics, Elsevier, vol. 27(2), pages 337-350, March.
    12. Li, Xianguo, 2005. "Diversification and localization of energy systems for sustainable development and energy security," Energy Policy, Elsevier, vol. 33(17), pages 2237-2243, November.
    13. Newbery, D., 2002. "Issues and Options for Restructuring Electricity Supply Industries," Cambridge Working Papers in Economics 0210, Faculty of Economics, University of Cambridge.
    14. Merton, Robert C., 1976. "Option pricing when underlying stock returns are discontinuous," Journal of Financial Economics, Elsevier, vol. 3(1-2), pages 125-144.
    15. Wolak, Frank A., 2003. "Diagnosing the California Electricity Crisis," The Electricity Journal, Elsevier, vol. 16(7), pages 11-37.
    16. Rafal Weron, 2006. "Modeling and Forecasting Electricity Loads and Prices: A Statistical Approach," HSC Books, Hugo Steinhaus Center, Wroclaw University of Technology, number hsbook0601, June.
    17. Powell, Andrew, 1993. "Trading Forward in an Imperfect Market: The Case of Electricity in Britain," Economic Journal, Royal Economic Society, vol. 103(417), pages 444-453, March.
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    Cited by:

    1. Sandro Sapio & Agnieszka Wylomanska, 2008. "The impact of forward trading on the spot power price volatility with Cournot competition," HSC Research Reports HSC/08/02, Hugo Steinhaus Center, Wroclaw University of Technology.

    More about this item


    Electricity; Market; Volatility; Supply Curve; Demand Curve; Fundamentals; Shocks;

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