Now showing 1 - 9 of 9
  • 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.
  • Publication
    Unit Commitment With Dynamic Cycling Costs
    (Institute of Electrical and Electronics Engineers, 2012-11) ; ; ;
    Increased competition in the electricity sector and the integration of variable renewable energy sources is resulting in more frequent cycling of thermal plant. Thus, the wear-and-tear to generator components and the related costs are a growing concern for plant owners and system operators alike. This paper presents a formulation that can be implemented in a MIP dispatch model to dynamically model cycling costs based on unit operation. When implemented for a test system, the results show that dynamically modeling cycling costs reduces cycling operation and tends to change the merit order over time. This leads to the burden of cycling operation being more evenly distributed over the plant portfolio and reduces the total system costs relative to the case when cycling costs are not modeled.
      712Scopus© Citations 53
  • 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.
      1102Scopus© Citations 210
  • Publication
    Multi-mode operation of Combined Cycle Gas Turbines with increasing wind penetration
    As power systems evolve to incorporate greater penetrations of variable renewables, the demand for flexibility within the system is increased. Combined Cycle Gas Turbines (CCGTs) are traditionally considered as inflexible units but those which incorporate a steam bypass stack are capable of open-cycle operation. Facilitating these units to operate in open-cycle mode is shown to improve system reliability and reduce emissions. It also yields benefits for the generators themselves via increased revenues (in some circumstances) and reduced cycling.
      2591Scopus© Citations 5
  • Publication
    Managing wind uncertainty and variability in the Irish power system
    This paper summarizes work that has been done to examine the impact of the uncertainty and variability of significant installed wind power on the Irish system. As more and more wind power is installed on the system, the operation of conventional plant on the system will be dramatically different. In this paper, three different aspects of the hour-to-hour operation of the Irish power system are examined. An innovative method to schedule the system is described, together with key results giving the effect of the uncertainty of wind on unit commitment of the system. The increased cycling of traditionally base-load units due to large amounts of wind power is quantified, and the steps to reduce this unwanted behavior are outlined. Finally, the use of intelligent decision tools based on sophisticated wind power forecasts for scheduling and provision of reserve is described.
      502Scopus© Citations 3
  • Publication
    Wind as a price-maker and ancillary services provider in competitive electricity markets
    (IEEE, 2010-07) ;
    Electricity markets are currently evolving to accommodate large scale penetration of wind generation. In this research, potential changes to the classification and role of wind generators in the Single Electricity Market (SEM), the market for Northern Ireland and the Republic of Ireland, are examined. The effect of wind generators opting to become price-making and the potential for wind generators to provide positive spinning reserve is investigated. By submitting bids for available generation, pricemaking wind generators can increase their revenues from the market and influence the average electricity price. Results also show reduced emissions and systems costs arise in allowing wind to provide spinning reserve.
      1615Scopus© Citations 10
  • Publication
    Multi-mode operation of combined-cycle gas turbines with increasing wind penetration
    As power systems evolve to incorporate greater penetrations of variable renewables, the demand for flexibility within the system is increased. Combined-cycle gas turbines are traditionally considered as relatively inflexible units, but those which incorporate a steam bypass stack are capable of opencycle operation. Facilitating these units to also operate in opencycle mode can benefit the power system via improved system reliability, while reducing the production needed from dedicated peaking units. The utilization of the multi-mode functionality is shown to be dependent on the flexibility inherent in the system and the manner in which the system is operated.
      1093Scopus© Citations 39