Grid Integration of Large Scale Renewable Generation – Initiatives in Indian Power System

摘要

India is continuously progressing in capacity addition through conventional as well asrenewable resources to meet its growing demand. Out of 234 GW present installed capacity,renewable capacity contribution is about 13%, which is primarily dominated by windgeneration (70%). Abundant Renewable Potential in the country presents excellent solution tomeet challenges like long term energy requirements, attaining energy security along withaffordability, addressing climate change concerns etc. Government is also promotingdevelopment of renewable generation through an attractive mix of fiscal and financialincentives as well as conducive policy environment. It is envisaged that more than 30 GWrenewable generation capacity shall be added in the 12th Plan period (2016-17). MNRE hasalso projected about 235 GW renewable capacity by 2030. Above quantum of envisagedrenewable capacity would lead to increase in renewable capacity penetration to 17% (2017) &33 % (2030) and renewable energy penetration to 9% (2017) & 16% (2030).Renewable energy is characterized by intermittency and variability which presents variouschallenges in its grid integration for maintaining grid stability & security in various scenarios.In order to address above challenges in high penetration regime, there is a need to introducemore flexibility in generation portfolio as well as consumption.Flexibility in generation is introduced through utilization of fast-ramping conventional energysources like Gas, Hydro, Pumped Storage Hydro, Energy Storage technologies like large scalebatteries (Flow, Li-Ion etc.). Indian system is dominated by coal based generation thereforeintroduction of flexibility in thermal generation though suitable technical and marketmechanism incentivizing operation of such plants providing flexibility also need to beexplored. In future, super critical technology generating units are to be deployed for coalbased generation, which can operate at the designed super-critical steam parameters between80-100% of rated capacity, providing added flexibility.Flexibility in consumption to be introduced through demand side management(DSM)/demand, encourages consumers to modify patterns of electricity usage. DSM/DR utilizes Smart Grid technologies, to reduce the operational cost of renewable integrationthrough measures such as load shifting and peak shaving. Also, other measures to smooth outthe intermittency and variability include enlarging the balancing area through strongtransmission interconnections, forecasting of renewable generation, real time monitoring ofrenewable generation, dynamic compensation etc.Considering envisaged renewable penetration level by 12th plan period (2016-17) and need ofaddressing challenges as well as infrastructure requirements to facilitate RE grid integration,extensive studies were carried out for evolution of “Green Energy Corridors”. As part of thestudy, challenges on account of grid integration of large scale renewable identified on GridOperational as well as System Planning front and suggested remedial measures suitable toIndian context.Studies identified transmission infrastructure requirement both at Intra state within state, forabsorption of RE power in the host state, as well as Inter-state, for transfer of RE power out ofthe host state. Strong grid interconnection shall also help in enlarging power-balancing area.Intermittent/variable nature of RE sources results in wide variations in quantum and directionof power flow on the Inter state high capacity transmission corridors. This requires placementof Dynamic reactive compensation in the form of STATCOM/SVC at strategic locations toprovide dynamic voltage support for smooth operation and maintaining grid security. Thisshall also help in addressing fault ride through issues in RE complexes.In addition, the study evolves requirement of other control infrastructure like establishment ofRenewable Energy management centres (REMC) equipped with advanced forecasting tools,weather monitoring stations as well as Real time measurement/monitoring schemes throughWAMS applications. Energy Storage requirement has also been identified to providebalancing reserves.In this paper, envisaged capacity addition of RE generation in next 5-6 years in various RErich states have been presented. Paper also deliberates challenges of integration of large scaleRenewable into grid and suitable mitigating measures. Studies for evolution of Green EnergyCorridors are also discussed. Paper highlights perspective transmissions plan for renewablesthat serve as a road map up to year 2030 in Indian context.