Research Output
1 - 10 of 12
Publication
The relationship between base-load generation, start-up costs and generation cycling
2008-12, Troy, Niamh, Denny, Eleanor, O'Malley, Mark
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
Unit commitment for systems with significant wind penetration
2009-05, Tuohy, Aidan, Meibom, Peter, Denny, Eleanor, O'Malley, Mark
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.
Publication
The viability of balancing wind generation with storage
2008-07, Feeley, C., Bryans, A. G., Nyamdash, Batsaikhan, Denny, Eleanor, O'Malley, Mark
This paper studies the impact of balancing wind generation with storage on the thermal plant mix and load for different levels of installed wind and storage, and under
different operational strategies. Moreover, the optimal time frame to be used for the optimization of the system operation
is studied and the possible revenue that can be generated by the system with wind and storage is calculated for different
scenarios. It is shown that the introduction of intermittent energy resources reduces the participation of the base-load plants and increases the peaking plants, and the increasing storage dramatically increases the participation of the midmerit plants. Furthermore, the mid-merit strategy and 24
hours time frame resulted in the best use of the system with wind and storage.
Publication
Demand side resource operation on the Irish power system with high wind power penetration
2011-05, Keane, Andrew, Tuohy, Aidan, Meibom, Peter, Denny, Eleanor, Flynn, Damian, Mullane, Alan, O'Malley, Mark
The utilisation of demand side resources is set to increase over the coming years with the advent of advanced metering infrastructure, home area networks and the promotion of increased energy efficiency. Demand side resources are proposed as an energy resource that, through aggregation, can form part of the power system plant mix and contribute to the flexible operation of a power system. A model for demand side resources is proposed here that captures its key characteristics for commitment and dispatch calculations. The model is tested on the all island Irish power system, and the operation of the model is simulated over one year in both a stochastic and deterministic mode, to illustrate the impact of wind and load uncertainty. The results illustrate that demand side resources can contribute to the efficient, flexible operation of systems with high penetrations of wind by replacing some of the functions of conventional peaking plant. Demand side resources are also shown to be capable of improving the reliability of the system, with reserve capability identified as a key requirement in this respect.
Publication
Developments in energy technology and policy research
2008-09, Denny, Eleanor, Burke, Daniel J., Fitzmaurice, Ronan, Keane, Andrew, Nyamdash, Batsaikhan, Richardson, Peter, Silke, Emma, Troy, Niamh, Tuohy, Aidan, Twohig, Sonya, Vittal, Eknath, O'Malley, Mark
Publication
Base-load cycling on a system with significant wind penetration
2010-05, Troy, Niamh, Denny, Eleanor, O'Malley, Mark
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.
Publication
Building a sustainable energy future : supply and demand options
2008-07, Denny, Eleanor, O'Malley, Mark
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.
Publication
Evaluating which forms of flexibility most effectively reduce base load cycling at large wind penetrations
2009-10, Troy, Niamh, Denny, Eleanor, O'Malley, Mark
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
A quantitative analysis of the net benefits of grid integrated wind
2006-06, Denny, Eleanor, Bryans, Garth, Fitz Gerald, John, O'Malley, Mark
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.
Publication
Operating the Irish power system with increased levels of wind power
2008-07, Tuohy, Aidan, Denny, Eleanor, Meibom, Peter, Barth, Rudiger, O'Malley, Mark
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.