Energy system analysis of utilizing hydrogen as an energy carrier for wind power in the transportation sector in Western Denmark Georges Salgi a, * , Bjarne Donslund b , Poul Alberg Østergaard a a Department of Development and Planning, Aalborg University, Fibigerstraede 13, DK-9220 Aalborg, Denmark b Energinet.dk, Fjordvejen 1-11, DK-7000 Fredericia, Denmark Received 1 October 2007; received in revised form 11 November 2007; accepted 26 November 2007 Abstract Hydrogen is an energy carrier that can potentially be used for introducing renewably generated electricity into the transportation sector. This paper presents a methodology for an overall energy system analysis of a hydrogen infrastructure, which meets a transportation hydrogen demand profile. The methodology starts by building a mathematical model for optimizing the economic operation of electrolyzers on the electricity mar- ket by use of Genetic Algorithms. Demand profiles from the optimization are then included in an overall energy system analysis model studying the electricity market and power balance system effects. A sample 2030 scenario analysis of Western Denmark is presented to demonstrate the applicability of the devised methodology. It is shown that Genetic Algorithms is a flexible tool that can be adapted to optimization problems involving energy storage. On the other hand, it is found that the ability of Genetic Algorithms to find a solution is highly dependent on initial variables and the storage constraint. Further analysis is required in order to test and expand the methodology and scenario results. Ó 2007 Elsevier Ltd. All rights reserved. Keywords: Genetic Algorithms; Operational optimization; Electricity market 1. Introduction Wind energy provided 22% of the electricity consumption in Western Denmark in 2006. The installed wind turbine capacity of 2400 MW already exceeds the local demand at certain hours of the year (Energinet.dk, 2007). On the other hand, transporta- tion has almost entirely relied on products derived from oil (DEA, 2005). The operational costs of a thermally dominated electricity system (such as in Denmark) are expected to increase with an increasing share of fluctuating wind power (Meibom et al., 2007a). While foreign exchange can contribute to balanc- ing fluctuating power, having local flexible technologies is essential for the development of a renewable energy market (Hvelplund, 2006). Various technological alternatives have been analyzed for increasing the system flexibility and econom- ically allowing the integration of higher shares of wind power in the Danish electricity system (Andersen and Lund, 2007; Lund and Mu ¨nster, 2006; Meibom et al., 2007b; Østergaard, 2005). A transportation fleet based on electricity is expected to have a positive technical influence on the electricity system flexibil- ity and stability at high wind power penetration (Lund, 2007; Mathiesen and Lund, 2008). The introduction of renewable en- ergy into the transportation sector requires an energy carrier that meets the performance characteristics demanded by mod- ern societies. Electrolytic hydrogen produced from wind and solar power is a potential carrier that has received considerable research attention during the previous decade (EHFCTP, 2006; EC, 2004; USDOE, 2007; IEA, 2004). Several studies have analyzed various aspects of a future energy system with hydrogen as an energy carrier in the trans- portation sector in Denmark. Sørensen et al. (2004) con- structed 2030 scenarios for Denmark with centralized and decentralized hydrogen production. The scenarios sought to maximize the utilization of wind power and study the impact on the storage size and hydrogen transportation problem. The study concluded that both centralized and decentralized * Corresponding author. Tel.: þ45 9635 7219; fax: þ45 9815 3788. E-mail address: georges@plan.aau.dk (G. Salgi). 0957-1787/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.jup.2007.11.004 Available online at www.sciencedirect.com Utilities Policy 16 (2008) 99e106 www.elsevier.com/locate/jup