Now showing 1 - 10 of 80
  • Publication
    Assessing Power System Flexibility for Variable Renewable Integration: A Flexibility Metric for Long-Term System Planning
    Many countries around the world have instituted policies with the aim of increasing the amount of installed variable generation (VG), such as wind and solar. A consequence of increased penetrations of VG is that changes in their output must be met by the remainder of a system’s resources so that the demand-generation balance is maintained. This paper proposes a highlevel methodology to assess power system flexibility. In this context, flexibility is the ability of a power system to deploy its resources to meet changes in the system demand and that of variable generation. The inclusion of such analysis at the long-term system planning stage will help to ensure that systems are optimally planned and operated with high levels of VG. Two case studies are presented which illustrate the flexibility assessment methodology and highlight some key issues relating to flexibility in the context of long-term planning.
  • Publication
    A sustainability strategy for Ireland’s electricity network
    (Risø National Laboratory for Sustainable Energy, 2009-09) ; ; ; ;
    The electricity system of Ireland is unique as it has no synchronous connections to other systems, while the existing non-synchronous connection provides limited flexibility. When coupled with a target of 40% electricity from renewables by 2020, exceeding any other country, the challenge is truly striking. However, this challenge also gives Ireland the opportunity to be the world leader in this area. The unique experience in solving this problem will provide the technology and knowledge to harness renewable energy sources globally and limit the dependency on petrochemicals. The continued development of the electricity distribution network as a smart network is a critical element of this process which spans electricity generation, transportation and energy end use. This paper described the various elements of ESB Networks’ sustainability strategy and the associated research themes being jointly pursued by ESB Networks, the Electric Power Research Institute (EPRI) and the Electricity Research Centre, University College Dublin.
  • Publication
    An integrated Building-to-Grid model for evaluation of energy arbitrage value of Thermal Storage
    Thermal Electric Storage (TES) has emerged as a promising technology for enhancing the flexibility of the built environment to participate in active Demand Side Management (DSM). These devices allow the decoupling of intra-day scheduling of electric power demand from the time of thermal energy end-use. Therefore, if enabled with communication with the grid, these devices can facilitate load shifting and energy arbitrage. This study evaluates the energy arbitrage value of smart TES devices in residential buildings across Ireland. A Building-to-Grid (B2G) model has been developed which integrates the buildings thermal dynamics and end-use constraints with the power systems economic dispatch model. The thermal behavior of the houses and the TES space heater and hot water tank is modeled through linear state space models for three different mid-flat archetypes. The optimization results show the load shifting and arbitrage potential of TES and its impacts on wind curtailment considering various penetration levels of these devices.
  • Publication
    The relationship between base-load generation, start-up costs and generation cycling
    (International Association for Energy Economics, 2008-12) ; ;
    Developments in the electricity sector such as the integration of increasing levels of renewable power, mainly wind, and the deregulation of electricity markets have resulted in some unconventional operation of base-load units. These units, which were originally designed for continuous operation, are now being forced into more flexible or cycling operation. This cycling operation results in serious physical degeneration of the unit’s components and hence incurs substantial costs to the plant operator. Using a planning tool of the Irish electricity system, the impact of increasing wind penetration on the operation of the base-load units is modelled. The results show that as wind penetration on the system increased, the base-load units were required to start up and shut down more often. However the units found to be cycled the most were not those with the cheapest start-up cost, but in fact those units with the shortest synchronisation time1. On the basis that the resulting cycling costs would increase the start-up costs of the base-load unit to some degree, the effect of increasing start-up costs on the operation of the base-load units was also examined. The results show that by increasing the start-up costs of base-load units, those units will be scheduled to operate in a more conventional base-loaded manner, the extent of which depends on the amount of wind power present.
  • Publication
    Evaluating which forms of flexibility most effectively reduce base load cycling at large wind penetrations
    (Energynautics, 2009-10) ; ;
    Increasing penetration of wind power on power systems worldwide is resulting in the unconventional operation of base-load generating units. These units which were originally designed for operation at full output are more frequently required to balance the variability of the wind. This results in increased start-stop cycling and hours at low load which causes severe deterioration to the plants components. Interconnection, storage and demand side management increase the flexibility of a power system and can balance variations in the wind power output, thus reducing the onus on thermal plants. This study will attempt to quantify which of these forms of flexibility is most effective at reducing base-load cycling on a thermal test system with a large amount of wind.
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  • Publication
    A small - signal stability analysis of DFIG wind generation
    This paper examines the small-signal stability impacts of high penetrations of doubly-fed induction generator (DFIG) wind turbines on power systems. It provides a basic overview of small-signal stability concepts and then examines the response of DFIG generation to two local contingency event. Using the New England 39 bus test system, this paper will demonstrate the stability implications of DFIG turbines utilizing terminal voltage control and fixed power factor control in response to reactive and active power loss events. By implementing terminal voltage control strategies in DFIG wind turbines, system stability is improved and allows for increased levels of wind penetration levels while maintaining a high level of system security.
  • Publication
    Rotor angle stability with high penetrations of wind generation
    This paper explores the relationship between wind generation, particularly the control of reactive power from variable speed wind turbine generators, and the rotor angle stability of the conventional synchronous generators in the system. Rotor angle stability is a dynamic phenomenon generally associated with changes in active power flows that create angular separation between synchronous units in the system. With larger penetrations of wind generation being introduced into power systems, there will be large flows of active power from asynchronous generation in the system. These asynchronous active power flows can aid in maintaining the rotor angle stability of the system. However, the manner in which wind generation injects reactive power into the system can be critical in maintaining angular stability of the synchronous units. Utilizing wind generation to control voltage and reactive power in the system can ease the reactive power burden on synchronous generators, and minimize angular separation in the system following a contingency event and can provide a significant level of support which will become increasingly important in future power systems.
      3608Scopus© Citations 215
  • Publication
    Ultra high wind energy penetration in an isolated market
    This paper addresses the market design implications of implementing ultra high (up to 42%) wind energy penetration in an isolated market. High wind penetration is becoming an increasing feature of many markets and the impact to such markets will need to be analyzed. In this paper, the Single Electricity Market (SEM) market design is analyzed in the context of increasing wind penetration and given the results of the recently published All Island Grid Study which indicated that ultra high wind capacity could be accommodated subject to certain key assumptions.
    Scopus© Citations 1  634
  • Publication
    Building a sustainable energy future : supply and demand options
    Fossil fuel depletion and concerns over global climate change are increasing the demand for sustainable and clean solutions for electricity generation. In the coming years some of the most difficult engineering challenges in history will have to be faced if a future with sustainable energy is to be developed. In light of this challenge investments in human infrastructure are essential in particular for early stage students who represent the generation who will have to truly solve future energy needs. This paper discusses an initiative in Ireland to foster an interest in energy issues for undergraduate students. A report made by the students on sustainable energy issues in Ireland is discussed here. The students focussed on recommendations that can be achieved in the short to medium term thus in many cases the infrastructural changes needed are simply a change in thinking or operational approach. One of the key infrastructural issues that arose is the importance of spatial planning in all areas of energy demand and supply.
    Scopus© Citations 3  554