Value of electric interconnection links in remote island power systems: The Spanish Canary and Balearic archipelago cases E. Lobato ⇑ , L. Sigrist, L. Rouco Universidad Pontificia Comillas, Madrid, Spain article info Article history: Received 28 November 2016 Received in revised form 7 March 2017 Accepted 27 March 2017 Keywords: Frequency stability Unit commitment Island power systems abstract This paper tackles the technical and economical value of island interconnection links in remote island power systems. For this purpose, a novel deterministic hourly unit commitment on a weekly basis is for- mulated including the possibility of interconnection links between islands. The unit commitment reflects the common practice of the majority of real island power system operators when operating their sys- tems: the economic dispatch is constrained in order to cover the loss of any on-line generating unit and the loss of any interconnection link between islands. Several islands of the Spanish Balearic and Canary archipelagos are used as illustrative real cases to assess the impact of existing and projected links between islands. The paper shows on one hand how reserve constraints drive the economical operation of real island power system. On the other hand, how the use of interconnection links not only enable the flow of cheaper generation power between islands, but also significantly contribute to the fulfillment of reserve constraints which translates into a cheaper and more sustainable island operation. Ó 2017 Published by Elsevier Ltd. 1. Introduction Island power systems are facing considerable challenges in meeting their energy needs in a sustainable, affordable and reliable way. In order to increase island sustainability, different generation- side measures (such as the use of renewable energy sources for power generation and use of energy storage devices for reserve provision), demand-side measures (such as the use of energy stor- age devices, implementation of demand side management actions and promotion of electric vehicles) and/or grid-side measures (interconnection of island systems with other island systems or the continental system) are available [1,2]. These options need to be customized on each specific island power system, depending on island features, opportunities and constraints [3]. This paper deals with the value of the last mentioned grid-side measures in isolated power systems. Electric interconnection by means of submarine cables (between islands or between mainland and an isolated island) pro- vides manifold benefits to isolated power systems: increase secu- rity of supply, reduce the island power system cost and introduces flexibility for increasing the penetration of variable renewable sources. Electric island interconnections are widely deployed in all over the world. Islands close to mainland are often already interconnected, while remoter islands cannot afford it in many cases. An alternative to remote islands is to search potential connections between islands. A comparison of climatic, physical and socio-economic features of 1087 island worldwide is per- formed in [4] to identify island with similar potentials of integrat- ing RES. Even though the effort made by the authors is very significant, the amount of interconnection between islands is not included as variable which can alter conclusions especially on smaller islands where as this paper will show, interconnectors modify the economic dispatch that satisfies reserve constraints. The operation costs of remote island power systems are higher not only because of expensive fuel transportation and lower effi- ciencies of power generation technologies (e.g., diesel), but also because of technical requirements on spinning reserves guarantee- ing frequency stability. Power system operators of island grids keep a certain amount of generation capacity as spinning reserve to ensure that the island is able to withstand the sudden outage of any generating unit and also address unforeseen load variations. Since each generating unit represents a significant fraction of the total generation in-feed in isolated power systems, spinning reserve requirements displace cheaper units in favor of more expensive units and increase the start-up costs of generators, being a key factor driving the economic dispatch of an island power sys- tem. It should be noted that the deployment of electric links between islands (both HVDC and AC) contribute in providing http://dx.doi.org/10.1016/j.ijepes.2017.03.014 0142-0615/Ó 2017 Published by Elsevier Ltd. ⇑ Corresponding author. E-mail address: enrique.lobato@comillas.edu (E. Lobato). Electrical Power and Energy Systems 91 (2017) 192–200 Contents lists available at ScienceDirect Electrical Power and Energy Systems journal homepage: www.elsevier.com/locate/ijepes