Now showing 1 - 10 of 12
  • 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.
      605
  • 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.
      2678
  • Publication
    Unit commitment for systems with significant wind penetration
    The stochastic nature of wind alters the unit commitment and dispatch problem. By accounting for this uncertainty when scheduling the system, more robust schedules are produced, which should, on average, reduce expected costs. In this paper, the effects of stochastic wind and load on the unit commitment and dispatch of power systems with high levels of wind power are examined. By comparing the costs, planned operation and performance of the schedules produced, it is shown that stochastic optimization results in less costly, of the order of 0.25%, and better performing schedules than deterministic optimization. The impact of planning the system more frequently to account for updated wind and load forecasts is then examined. More frequent planning means more up to date forecasts are used, which reduces the need for reserve and increases performance of the schedules. It is shown that mid-merit and peaking units and the interconnection are the most affected parts of the system where uncertainty of wind is concerned.
      3180Scopus© Citations 598
  • Publication
    Operating the Irish power system with increased levels of wind power
    This paper summarises some of the main impacts of large amounts of wind power installed in the island of Ireland. Using results from various studies performed on this system, it is shown that wind power will impact on all time frames, from seconds to daily planning of the system operation. Results from studies examining operation of the system with up to approximately 40% of electricity provided by wind show that some of the most important aspects to be considered include the type of wind turbine technology, the provision of reserve to accommodate wind forecasting error and the method used to plan plant schedules.
    Scopus© Citations 12  840
  • Publication
    Rolling unit commitment for systems with significant installed wind capacity
    As wind power penetration grows, the amount of reserve needed on the system also grows, due to the increases in the uncertainty of wind power, which grows larger as forecast horizon increases. By scheduling the system more often the amount of extra reserve to be carried to cater for wind uncertainty decreases, depending on the flexibility of plant on the system. This reduces the costs of operating the system. There is a trade off between reduced costs due to more frequent commitment, the ability of wind forecasts to be made more accurately, and the increased costs of more flexible plant. This paper examines the benefits of committing the system more frequently, and how different factors such as reliability of the system, accuracy of the forecasts and plant mix impact on this.
    Scopus© Citations 53  690
  • Publication
    A quantitative analysis of the net benefits of grid integrated wind
    Throughout the world significant development is being encouraged in wind energy for electricity generation. A complete cost and benefit analysis has been conducted in this paper on grid connected wind generation. It takes into account system costs such as reserve requirements, start-up and ramping implications for conventional plants as well as wear and tear costs. The benefits of wind generation analysed include the emissions benefits, the saving on the fuel bill, the electricity generated and the capacity value. These costs and benefits are then used to generate net benefit curves for wind generation and the sensitivities of the curves are tested with changes in the underlying assumptions. A complete unit commitment model with wind generation is used to determine the dispatches upon which the costs and benefits are calculated.
    Scopus© Citations 12  414
  • Publication
    Base-load cycling on a system with significant wind penetration
    Certain developments in the electricity sector may result in suboptimal operation of base-load generating units in countries worldwide. Despite the fact they were not designed to operate in a flexible manner, increasing penetration of variable power sources coupled with the deregulation of the electricity sector could lead to these base-load units being shut down or operated at part-load levels more often. This cycling operation would have onerous effects on the components of these units and potentially lead to increased outages and significant costs. This paper shows the serious impact increasing levels of wind power will have on the operation of base-load units. Those base-load units which are not large contributors of primary reserve to the system and have relatively shorter start-up times were found to be the most impacted as wind penetration increases. A sensitivity analysis shows the presence of storage or interconnection on a power system actually exacerbates base-load cycling until very high levels of wind power are reached. Finally, it is shown that if the total cycling costs of the individual base-load units are taken into consideration in the scheduling model, subsequent cycling operation can be reduced.
    Scopus© Citations 210  1098
  • Publication
    The psychology of energy efficiency labels: Trust, involvement, and attitudes towards energy performance certificates in Ireland
    Energy performance certificates (EPCs) are a widely implemented policy intended to inform building owners, occupiers, tenants, real estate agents and other relevant groups about the energy performance of dwellings (e.g., level of comfort and/or expenditure) and stimulate the investment in energy efficiency of buildings. EPCs for buildings are not a recent concept, for example, in the USA, the “Green Lights” programme was launched in 1999, which later expanded into the “Energy Star Building” programme. To date, all members of the European Union have formally introduced EPCs, although the stage of implementation and the name of the label differ between the various member states. In this paper we focus on EPCs for buildings in Ireland, which stands out as having one of the most well-established and reported databases within the EU.
    Scopus© Citations 15  471
  • 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  557