تجزیه و تحلیل شبیه سازی تاثیر تجارت تولید گازهای گلخانه ای در یک نیروگاه برق بدون سودمندی

Non-utility power plants can competitively participate in open electricity market to reduce operational costs but in the absence of pollution charges or emissions trading such generators are tempted to cause greater pollution for profit maximization. This paper presents a solution that incorporates pollution charges for nitrogen oxides and sulphur dioxide emissions in line with existing national environmental quality standards and a new carbon dioxide emissions trading mechanism. A novel approach has been used for allocation of allowable emissions that favors efficiently fuelled and environmentally friendly operation for maximizing profit. Impact of proposed carbon trading on economical utilization of enormous indigenous coal reserves has been analyzed and determined to be acceptable. Software developed in this paper, harnessing Sequential Quadratic Programming capabilities of Matlab, is shown to be adequate simulation tool for various emissions trading schemes and an useful operational decision making tool for constrained non-linear optimization problem of a non-utility power plant.

It has been suggested that we are now entering the age of Natural Capital, in which resource depletion and environmental impact become key drivers (Harris, 2006). Both of these drivers are simultaneously taken care of while developing a novel approach to allocate emission allowances in this paper. Particular care needs to taken while deciding upon price of carbon dioxide (CO2) emissions per ton. It should be high enough to deter any power generator from maximizing its own profit on the cost of environmental degradation to society at large. At the same time, carbon price must not be so high that it changes merit order of coal on supply curve which is possible if generators have to internalize their emissions costs (Denny and O’Malley, 2009). A change in merit will impede beneficial utilization of huge indigenous coal deposits, estimated to be more than 175 billion ton (Siddiqui, 2007), that are yet to be exploited. This paper proposes an appropriate price for CO2 emissions that is shown to achieve both above mentioned objectives. Findings of this research are intended to act as guidelines for developing future government policies on energy and environment. In addition to causing environmental damage and depletion of fossil fuel reserves, generators may use market power to achieve huge financial benefits by unfair practices like strategic pricing, capacity withholding and induced transmission congestion (Koesrindartoto et al., 2005). Market power mitigation procedures need to be introduced to penalize such unfair practices and ensure that benefits of deregulation reach electricity consumers. Appropriate mitigation procedures may be determined by agent-based simulation of market conditions and bidding mechanisms. Results from various agent-based simulations demonstrate that the multi-agent system approach enables effective modelling and simulation of the electricity markets (Yu and Liu, 2008). This work presents a test-bed that can simulate economical operation of a thermal non-utility power plant (NUPP) under various possible market structures. This software is also intended to serve as an operational decision making tool for a manager of a thermal NUPP. Consequently, this development is of interest for both academic and practical circles due to its two distinct dimensions. Operational cost and amount of CO2 emissions are determined and compared for four market scenarios; business as usual (BAU) before deregulation, deregulation without emissions trading (NO-ET), 90% free-allocation (90%-FA) of allowances and 90% auctioning (90%-AC) of allowances. Optimal bidding strategies are established for a NUPP simultaneously operating in energy and environmental markets. A daily emission bid and twenty-four hourly power supply and demand bids are finalized on a day-ahead basis. Hourly generation levels for each generating unit of a NUPP are determined as well. Section 2 discusses current restructuring trends in Power Sector of Pakistan and proposes a new deregulated market model for future. Various emission trading schemes are explored in Section 3. Section 4 presents a mathematical model capable of representing interactive operation of electricity and emission markets on an hourly basis. Section 5 explains optimization algorithm for daily operation. A case study of an oil-fired NUPP containing five generators is presented in Section 6. Section 7 shows simulation results and discusses the most important ones. Finally, Section 8 presents conclusions and Section 9 offers insight into future work.

Novel approach used for allocation of emissions allowance ensures that generators are run close to their most efficiently fuelled and hence most environmentally friendly operation levels. Furthermore, proposed price of CO2 emissions per ton is high enough to deter any power generator from maximizing its own profit at the cost of environmental deterioration for society. Both of these conclusions are deduced from the fact that when ET is introduced with 90%-FA, then emissions decrease by 17% with a minor reduction in cost. Moreover, proposed carbon price is not high enough to change merit order of coal on supply curve and hence favors beneficial utilization of huge indigenous coal reserves. It has been determined that, even after ET, average tariff for coal fired plant still remains less than US$ 62.5 per MWh (Rs. 5,000 per MWh) compared to an oil-fired plant incurring a cost that is above US$ 125 per MWh (Rs. 10,000 per MWh). Higher emissions under 90%-AC from oil-fired NUPP does not mean failure of the scheme because total emissions from all plants in a power system are shown to decrease under a similar scenario in Zhou et al. (2008). Similarly, higher cost due to 90%-AC implicates that this market structure makes operation of a highly polluting oil-fired plant less economical and hence favors clean renewable energies and introduction of emission abatement technologies in fossil fuelled plants. This software development is applicable in general to any thermal power plant in Pakistan and not specific to this particular case study or plant setup. It can accommodate four distinct aspects of hourly operational cost that are cost of fuel, cost due to NOx and SO2 emission charges, cost and allowance of CO2 emission and cost of power bought and revenue from power sold. Presented work has full potential to be universally applied to any thermal power plant containing multiple generators and operating simultaneously in a PX and an environmental market catering for CO2 emissions. Developed test-bed can simulate economical operation of a NUPP without ET and with ET that can have any percentage mixture of free-allocation and auctioning. This test-bed is useful for much needed analysis of impact that will result from various emissions trading schemes on a NUPP before actual implementations. So that is why it is a beneficial tool for academic researchers and policy makers that design deregulated market structures. Suitability of this software as an operational decision making tool for a manager of a NUPP is demonstrated by self-generation levels of Fig. 3 and Fig. 4 as well as hourly power trade bids of Fig. 5.