K. Srikanth Reddy

Profit-based conventional resource scheduling with renewable energy penetration

Technological breakthroughs in renewable energy technologies (RETs) enabled them to attain grid parity thereby making them potential contenders for existing conventional resources. To examine the market participation of RETs, this paper formulates a scheduling problem accommodating energy market participation of wind- and solar-independent power producers (IPPs) treating both conventional and RETs as identical entities. Furthermore, constraints pertaining to penetration and curtailments of RETs are restructured. Additionally, an appropriate objective function for profit incurred by conventional resource IPPs through reserve market participation as a function of renewable energy curtailment is also proposed. The proposed concept is simulated with a test system comprising 10 conventional generation units in conjunction with solar photovoltaic (SPV) and wind energy generators (WEG). The simulation results indicate that renewable energy integration and its curtailment limits influence the market participation or scheduling strategies of conventional resources in both energy and reserve markets. Furthermore, load and reliability parameters are also affected.

Potential benefits of electric vehicle deployment as responsive reserve in unit commitment

Modernization of electric grid and deregulation of electricity market put forward many tough challenges both technically and economically. Improving the power system reliability is a major task amongst them, which depends on the responsive reserve capacity and its response time in case of contingency. Fast response time and the possibility of Electric Vehicle (EV) participation in deregulated electricity market environment can be exploited in the deterministic scheduling of EV as responsive reserve (RR) in unit commitment (UC) problem to enhance power system reliability at reasonable cost and facilitating economic feasibility of EV deployment. To investigate this concept conventional thermal units are scheduled considering EV as responsive reserve which aims at minimizing the cost for independent system operator (ISO) in satisfying load and reserve requirements under stringent constraints imposed by generation units and yielding extra income through selling EV capacity into reserve markets to maximize the revenue with lower risk of degradation and charge outage. From the results it is observed that in the present scenario, selling EV into reserve market would fetch more revenue than the energy market counterpart and at the same time EV reserve procurement also minimizes the operational cost for ISO when compared to conventional reserve procurement.

Eco-economie sizing of autonomous hybrid energy system (AHES) using particle swarm optimization (PSO)

Deployment of distributed energy resources has brought the concept of autonomous hybrid power systems at community levels and remote areas into limelight. In such systems, proper sizing of energy resources at design stage is very crucial to meet energy requirements at minimum cost. Other than technical and economic constraints, system sizing should abide the preservation of environmental interests pertaining to sustainability needs. To investigate this problem, a sizing methodology preserving both economic and environmental interests is proposed in this paper. The problem for component sizing is formulated as an optimization problem with cost minimization objective including both cost and emissions. Particle swarm optimization (PSO) method is then applied to arrive at optimal solution, minimizing the dual objectives i.e., of system cost and embedded emissions. The proposed optimal sizing methodology is simulated for an autonomous hybrid power system renewable energy sources (photovoltaic, wind energy), conventional sources (diesel generator) and energy storage (battery systems). The dual objective function is optimized with different weightages for cost and emissions and the results demonstrates that, mutual exclusive nature of cost and emissions can be addressed with the tradeoff solution.

Modelling and analysis of resource scheduling in restructured power systems considering wind energy uncertainty

ABSTRACT Concerns over rapid transformation of global climate patterns resulted in wide deployment of renewable energy sources especially wind energy. However, intermittent nature of wind energy makes resource scheduling aspect of system operator more complex. The emerging deregulation policies have added to the complexity of scheduling problem. Therefore, treating and scheduling of wind energy on deterministic basis would result in non-optimal energy dispatch and increased operation cost over scheduling horizon. This paper focuses on optimal scheduling methodology of wind energy in day ahead market (DAM) considering expected costs due to wind uncertainty in real time (RT) spot market under deregulated market structure. This paper introduces various possible costs, namely, spot market compensation cost, additional reserve cost and rescheduling cost applicable to deviation in scheduled power from DAM to spot market. The costs can be derived from front-end information of DAM, historical and statistical estimate of RT market conditions. The effectiveness of proposed methodology is examined using IEEE 30 bus system with thermal and wind energy generators. In addition, sensitivity analysis is performed to examine the effect of incentive margin on DAM scheduling. Simulation results are presented, discussed and affirmed the effectiveness of proposed scheduling methodology.

Demand side management with consumer clusters in cyber-physical smart distribution system considering price-based and reward-based scheduling programs

This study presents a demand side management (DSM) strategy for a cyber-physical smart distribution system (CPSDS). The proposed approach uses the price-based as well as reward-based DSM schemes as a part dual objective function. The objectives of the proposed scheduling approach comprise the profit maximisation objectives of demand response aggregator agent (DRAA) and network performance objectives of the distribution system operation agent. The same are achieved by providing incentives to the participating customers. The incentive information is communicated to responsive load agent (RLA) using cyber infrastructure (communication channels, sensors and cloud storage systems) and thus allowing customers to select the incentive program of their own choice as per their flexibility. The real-time implementation of the program is considered to have direct load control based once the event trigger acknowledgement is received by DRAA/utility from RLA for control action on responsive loads. The proposed price-based and reward-based DSM framework in CPSDS is evaluated using IEEE 37 bus test system. The simulation results of proposed dual objective price-based and reward-based mechanism are presented, discussed and compared with single objective price-based approach. The same demonstrates the improved tradeoff between techno-economic aspects of distribution system operation.

Price Based Resource Scheduling with Renewable Energy in Emission Constrained Market Structure

The deregulation and introduction of green technologies are the two key developments took place in electricity sector during the last decade. These developments have brought in several features into the system and increased complexity of system at planning ans well as operation level of power system. This paper deals with one of the key procedure of power system operation i.e., resource scheduling. In this paper, multi-objective aspects of resource scheduling in deregulated environment are examined treating both conventional and renewable energy sources as identical entities as per the market participation is concerned. The scheduling problem is formulated as a multi-objective problem with both economic as well as environmental aspects. The network and conventional/thermal generator constraints are remodelled pertaining to the market participation of renewable energy sources. Also, different scheduling scenarios are generated for analyzing the variation of different system and market parameters. The simulation results confirms the influence of weight factors or the importance assigned to objectives while the same have also affected the network parameters like scheduled renewable energy, reserve offer to market. Therefore, the proposed methodology can help in generation company/ independent system operator (ISO) in the selection of particular scheduling scenario pertaining to imposed compliances on emissions/renewable energy deployment obligations.

Environmental sustainability analysis of solar photovoltaic (SPV) systems

Renewable energy technologies (RET) present an emission free means of energy harvesting in the current energy scenario demanding sustainable needs. However, the production process of RETs especially solar photovoltaic (SPV) is material and energy expensive process. In this paper such material and energy intensive production processes of SPV systems are analyzed. The systems are analyzed up to the production stage with focus given to energy and material differentiation among different stages of production. The evaluation of emissions during production stage is carried out for a 1KWp SPV system. A comparison is made between different types of technologies i.e., mono, poly, thin film CdTe and ribbon Si. Also, comparison of sustainability aspects of rooftop and ground mounted installations is carried out. Results indicate that, in case of mono Si technology emissions during wafer production phase are pronounced compared to cell and module preparation stages. In poly and thin film technologies, emission share of wafer stage is comparable with module preparation stages. In ribbon Si, energy inputs accounted for higher emissions rather than materials as in case of other technologies. In the mounting structures, in roof structures resulted in least emissions through material savings while, ground mounting structures are environmentally expensive due to high material consumption. Also, the emission share of materials used in production stage is reduced linearly from mono Si to ribbon Si when in roof mounting is used. Therefore, thin film CdTe, ribbon Si presents an environmentally cheaper options of harnessing solar energy and production processes of technologies like mono Si, poly Si need to be improved to make them environmentally sustainable.

Cost-emission analysis of electric vehicle as contingency reserve in resource scheduling

Emission free electric vehicle is one of potential entity through which global warming issues can be resolved. Besides greener transportation, EV can also be used to negotiate electricity utility costs imposed by several network constraints like load-demand balance, reliability criteria etc. Thriving on reliability assurance in modernized electric grids, a multi-beneficiary model exploiting EV capability of being a contingency reserve is developed in this paper. Additionally, variability of EV reserve procurement in conjunction with environmental constraints is examined through cost-emission analysis. Further, the threshold limit for economic and environmental balance is defined and evaluated. The proposed reserve procurement concept is then simulated on a test system with both conventional and renewable energy technologies (RETs). For enumerating cost emission analysis, various dispatch scenarios are put forward. The simulation results shows the potential of EV in both environmental and economic perspectives when participated in reserve market. It is also observed that, apart from cost and emission, technical performance of electric network is also altered. Also, the amount of RETs and EV procured by independent system operator (ISO) is influenced by the importance (weight factor) given to emission minimization objective. The results indicate that, apart from amount of EV procured, percentage share of different cost components are also influenced by both scheduling scenario and energy market prices.