G.S. Krishna Priya

Emission constrained power system planning: a pinch analysis based study of Indian electricity sector

In the light of rising electricity demands and a need to curb carbon dioxide emissions, this article investigates the problem of power system planning with emission targeting. A pinch analysis based approach is utilised here. The key aspect of this study is investigating the parameters that decide the priority of one type of power plant over another. For this, a quantity called prioritised cost, a trade off between cost incurred and emission from a new power plant is identified. In addition to cost and emission factor of a power plant, a third parameter, the present state of the system, also plays a significant role in deciding a power plant’s prioritised cost. The analysis done proves that new power plants can be added to the system in the order of their prioritised cost. This methodology is applied to Indian power sector as a case study. Two different problems, involving minimisation of investment and annualised cost, are considered. It is observed that renewables are slightly more favoured when the objective is to minimise overall cost and not just the capital investment. In both cases, the energy mix is still dominated by coal-based power generation. The share of renewables was seen to increase with more stringent emission targets when the objective was to minimise overall cost.

Optimum sizing of supply equipment for time varying demand

Abstract The sizing of supply equipment to meet a time varying demand is an important engineering problem. Optimal sizing of various supply equipment can reduce the overall cost of the supply system significantly. In this paper, the screening curve methodology, originally proposed for planning electrical power system, is extended to address various process system related problems: cost optimal sizing of various pumps to satisfy time varying water demand, ideal mix of various lighting options for a given lighting load, etc. These examples illustrate that the proposed methodology is a simple, versatile, and powerful tool for appropriately sizing various equipment to satisfy time varying demands during grassroots design. During debottlenecking, supply system is expanded; new supply equipment are installed along with appropriate utilisation of existing supply equipment. A methodology is proposed to address expansion planning of various supply equipment during debottlenecking and demonstrated using an example of debottlenecking an air conditioning system.

Screening Curve Method for Optimum Source Sizing to Satisfy Time Varying Demand

Abstract Screening curve method was originally proposed for sizing various power plant capacities to satisfy time varying power demand. Though screening curve methods are normally used for power system planning, they can be applied on a wide range of process systems related problems. In this paper the concept of screening curve methodology is extended to determine optimal sizing of various sources to satisfy time varying demands. Applicability of the proposed methodology is illustrated with various examples: cost optimal sizing various pumps to satisfy time varying water demand, energy optimal sizing of various reciprocating compressors to deliver time varying compressed air requirement, and cost optimal sizing of various air conditioning systems to satisfy time varying cooling requirement.

Optimum source sizing to satisfy time varying demand

The Screening curve method is a simple technique used in power system planning since decades. Though it is normally used for power system planning, it is possible to apply the method to a wide array of engineering applications. In this paper, the screening curve based graphical methodology is applied to minimize the energy requirement of a compressed air system and to minimize the total annualized cost of a refrigeration system. However, the graphical screening curve methodology is not directly applicable to expansion planning problem with existing sources. A tabular methodology is proposed to optimize expansion planning of systems with time varying demands. The proposed methodology is demonstrated with an example of refrigeration system. Proposed graphical as well as tabular methodologies are simple to understand and effective to optimize a diverse range of engineering problems.