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Energy Systems and Technologies for the Coming Century ...

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Wind power impacts, electricity storage <strong>and</strong> heatmeasures – a time scale perspectiveKarsten Hedegaard a , Peter Meibom ba <strong>Systems</strong> Analysis Division, Risø DTU, Technical University of Denmark, 4000Roskilde, Denmarkb Intelligent <strong>Energy</strong> <strong>Systems</strong> Programme, Risø DTU, Technical University of Denmark,4000 Roskilde, DenmarkAbstractIntegrating large amounts of wind power in energy systems poses balancing challengesdue to <strong>the</strong> variable <strong>and</strong> only partly predictable nature of wind. In this paper, using <strong>the</strong>case of West Denmark in 2025 with an expected 57 % wind power penetration, windpower impacts are analyzed, indicating <strong>the</strong> physical potential <strong>for</strong> power balancing ondifferent time scales. This is done by analysing <strong>the</strong> length of high <strong>and</strong> low net loadperiods; expressing <strong>the</strong> two overall challenging operational situations. The resultsindicate a potential <strong>for</strong> flexible technologies capable of charging/activating dem<strong>and</strong> <strong>and</strong>discharging/inactivating dem<strong>and</strong> in periods of one hour to around half a day, providingintra-day balancing. More interestingly, <strong>the</strong> occurrence of consecutive negative net loadperiods with lengths of 0.5-3 days, consecutive high net load periods of 0.5-0.75 day <strong>and</strong>of average negative/high net load periods with lengths of one to several days alsoindicate a potential <strong>for</strong> flexible technologies capable of balancing intra-week. Finally, <strong>the</strong>results also indicate a potential <strong>for</strong> seasonal balancing.1 IntroductionSeveral countries expect large wind power penetrations in <strong>the</strong> future <strong>and</strong> this will posesystem balancing challenges due to <strong>the</strong> variable <strong>and</strong> only partly predictable nature ofwind. The Danish energy system <strong>for</strong>ms an interesting case <strong>for</strong> analysing <strong>the</strong>sechallenges. This is firstly due to a high amount of wind power, corresponding to almost20 % of annual electricity consumption. Secondly, around 50 % of <strong>the</strong> power productionis based on combined heat <strong>and</strong> power (CHP), resulting in a large amount of heat boundpower production [1]. As a result, in periods with high wind power production, high heatdem<strong>and</strong> <strong>and</strong> low electricity dem<strong>and</strong>, <strong>for</strong>ced electricity export occurs. Fur<strong>the</strong>rmore, inorder to ensure stable system operation <strong>and</strong> meeting electricity dem<strong>and</strong> over <strong>the</strong> year,<strong>the</strong>re is a significant need <strong>for</strong> regulating power <strong>and</strong> ancillary services. The target of 50 %wind power in Denmark in 2025 points to significantly increasing challenges of windpower integration in <strong>the</strong> near future [2]. Moreover, considering <strong>the</strong> long term goal of <strong>the</strong>Danish Government of phasing out <strong>the</strong> use of fossil fuels, an efficient utilisation of <strong>the</strong>wind power is important.In addition to enhancing <strong>and</strong> exp<strong>and</strong>ing <strong>the</strong> existing power grid <strong>and</strong> interconnectionswith neighbouring countries, studies suggest that suggest that use of large heat pumps<strong>and</strong> electric boilers in combination with heat storages in CHP systems are economicallyfeasible in increasing system flexibility <strong>and</strong> integrating wind power [3-6]. Individual heatpumps can also contribute with system benefits <strong>and</strong> are considered to have highfeasibility in areas outside district heating [7] [8]. When operated intelligently, batteryelectric vehicles also offer high potentials in facilitating <strong>the</strong> integration of wind power [1,9]. In addition, dedicated electricity storage technologies such as large batteries, flowRisø International <strong>Energy</strong> Conference 2011 Proceedings Page

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