The green symphony for efficient T&D infrastructure

Grid integration and T&D are vital for renewable energy’s growth and sustainability. Leading experts discuss HVDC’s impact on seamless transmission. DERs, like microgrids, empower local energy sharing and grid stability.

In the ever-evolving world of energy, the quest for efficiency and sustainability has become paramount. Grid integration and Transmission and Distribution (T&D) infrastructure play a pivotal role in this pursuit, laying the foundation for a cleaner and greener future.

As we bid adieu to the age of linear notes, we embrace the non-linear symphony of renewable energy integration. Grid integration and T&D infrastructure stand at the heart of this grand performance, orchestrating a future that harmoniously blends efficiency and sustainability. Together, we navigate this exciting path as we usher in a new era of energy brilliance. 

Key technologies for efficient renewable energy transmission 

As the world moves towards greater penetration of renewable energy (RE), one of the key challenges lies in developing the transmission infrastructure to handle the additional power generation. In this context, high-voltage direct current (HVDC) technology significantly contributes to efficient power transmission, facilitating this transition.

We face a significant issue with harmonics, as 70 percent of the load consists of non-linear loads. Whether it’s a smaller or larger system, the challenge remains substantial due to low system impedance and high voltage distortions. To tackle this, proper harmonic mitigation techniques are essential. Only 30 percent of the distribution load was non-linear in the past, but this has drastically changed.

Mr. M. Venkatshan, DGM SRLDC, Grid India, emphasises the evolving nature of HVDC’s purpose. Initially designed to link five regions operating at distinct frequencies, HVDC required advanced technology and robust control systems. However, after December 2012, the focus shifted towards nationwide integration, connecting all regions through a network of alternating current (AC) and parallel direct current (DC) lines. This transition transformed the primary objective from regional power export to managing AC line flows more effectively, considering dynamic power import and export demands. Consequently, HVDC deployment has become more strategic, catering to specific power transfer requirements rather than being arbitrarily placed.

Regarding HVDC’s crucial role, Mr. Baldev Raj Narang, CEO of Clariant Power Systems Ltd., emphasises the significance of power electronics in various sectors, including utility, consumption, generation, and transmission. He highlights that power electronics play a pivotal role in handling loads, as their performance is heavily influenced by the nature of the loads they are subjected to.

Mr. Baldev exemplifies the relevance of power electronics in real-life scenarios. He mentions an issue faced by a communications company, Jio, during the installation of power electronic devices at their Nagpur facility. The challenge arose due to the absence of conventional loads and reliance solely on leading loads. With devices connected to the grid over significant distances, a high leading load condition resulted due to high line impedance and capacitance, creating operational difficulties. This underscores the importance of considering load pattern imbalances when evaluating grid integration technologies.

Echoing the significance of HVDC, Mr. Vikram Gandotra, Head of Utility Sales & Strategies at Siemens Ltd., emphasises how a strong grid system forms the backbone of successful large-scale renewable power integration. He praises the planners’ foresight in establishing a robust national grid comprising five strong regions, now under the control of Grid-India, formerly POSCO. This well-structured grid foundation has enabled the seamless integration of abundant solar and wind power, a feat that would have been unattainable without it. HVDC’s role in this integration is undeniable, providing a means for substantial inter-regional power transfer capability. It is a critical technology for a vast country like India with diverse energy generation and consumption centres.

We primarily rely on conventional passive solutions for renewable energy (RE) solutions in India. Although a 6 percent reactor can resolve prominent harmonics like the fifth or seventh, overseas countries delve deeper into the 21st or 23rd harmonics. However, practical implementation and modelling for higher harmonic filters still need to be improved in India. An LCR circuit with more substantial resistance, ten times more expensive than a reactor, is required in bigger systems. While harmonic levels remain low, they still surpass grid levels. Hence, power quality solutions must be implemented universally in microgrids or large grids to address this significant challenge. 

Harnessing microgrids for DERs to enhance resilience, local energy sharing, and reduce congestion

Microgrids integrating Distributed Energy Resources (DERs) have made notable strides in enhancing resilience, enabling local energy sharing, and reducing congestion. Operating independently from the main grid, microgrids bolster resilience during outages. They facilitate energy sharing among communities and alleviate grid congestion by absorbing excess local energy, ensuring smoother distribution. Continued advancements, supportive policies, and investments are vital to fully unleashing the potential of microgrids for DER integration, driving greater resilience, energy sharing, and congestion reduction. 

Mr. Sirish S. Garud, Director for Renewable Energy Technology at TERI, believes renewables will play a crucial role in the future, particularly with the government’s plans to electrify hard-to-abate sectors like transportation and industries. The focus is on expanding renewables, including hydrogen production, where hydrogen could serve multiple purposes as fuel and a reaction agent. Upgrading the grid with smart metering and demand-side management is essential to accommodate increasing demand due to digitalisation and IT advancements. Capacity building in the electric sector, efficiency improvement, and infrastructure development are vital, especially with emerging technologies and business models. Grid-level storage projects are underway to ensure reliability and prevent power failures. Investment in grid simulation and prediction capabilities will enhance overall grid performance.

Contrasting the previous viewpoints, Mr. Baldev raises concerns about grid integration for renewable energy (RE). He suggests that microgrids or Distributed Energy Resources (DERs) could offer potential solutions at local levels, operating independently from the main grid. Nonetheless, he stresses the indispensability of a robust grid, big or small, for effective renewable utilisation. Looking ahead, he highlights that battery backup will become crucial, and the battery must function in a grid-forming mode to ensure optimal performance.

Considering the variable nature of RE as a source, grid integration necessitates storage to enable continuous usage for 24 hours. Only with adequate storage can renewable energy be harnessed to its fullest potential.

Utilities’ challenges in maintenance and monitoring

Mr. Vikram delves into utilities’ adaptation to microgrids and the challenges of monitoring and maintaining them. He defines a microgrid as a system encompassing energy generation and consumption within a confined area, with two types: off-grid and on-grid microgrids. In the case of grid-connected microgrids, energy is drawn from the grid when generation falls short of demand, making the grid the last resort.

Mr. Vikram points out that grids were originally designed with significant investments to function as electricity suppliers, not backup resources. Microgrids should complement and support the grid with local generation, meeting the needs of larger consumers. However, the practical implementation of such scenarios has yet to be fully observed. In areas where the demand is not substantial, utilising local microgrids to provide electricity becomes a viable and economically attractive solution. The business case for implementing such microgrids is strong.

Data Analytics and AI 

In today’s rapidly evolving energy landscape, data analytics and artificial intelligence (AI) have emerged as crucial tools for optimising grid integration and achieving efficient energy infrastructure. Utilities and grid operators can make informed decisions, enhance system performance, and ensure seamless integration of renewable energy sources by harnessing the power of advanced analytics and AI technologies.

Considering this, Mr. Venkateshan sheds light on the current initiatives Grid-India took in employing AI tools. The organisation actively explores renewable energy forecasting as part of the Green Energy Corridor scheme. They have also implemented an in-house reactive forecasting tool based on artificial intelligence. Furthermore, they are striving to develop real-time forecasting capabilities. Though still in its early stages, AI has commenced, and there are ambitious plans to expand its application. This demonstrates their commitment to embracing advanced technologies for grid optimisation and enhancing overall energy management efficiency.

Government policies and incentives empowering T&D efficiency

In the realm of grid integration and energy infrastructure, the role of policies is of utmost significance, as underscored by Mr. Baldev’s insights. While acknowledging the existing gaps in policy implementation, he draws attention to critical issues relating to renewable integration and distribution companies. The lack of thorough policy analysis before implementation has resulted in challenges, such as the forced adoption of STATCOM without adequate evaluation of its efficacy.

There are complexities faced by distribution companies, grappling with management, financial, and efficiency issues that lead to substantial losses. Power quality is particularly concerning, with distribution transformers succumbing to the impact of harmonics exported by consumers exceeding specified limits. Although regulations are in place, compliance must often be revised, necessitating penalisation to ensure adherence.

Highlighting the importance of tailored utility regulations, Mr. Baldev lauds Tamil Nadu’s example as a working system for effectively controlling power quality. Moreover, he addresses safety concerns in commercial installations, emphasising the need for streamlined regulations and effective implementation to tackle issues arising from unbalanced conditions and specific harmonics flowing through the neutral. These observations shed light on the critical role of well-designed and diligently implemented policies in shaping a resilient and efficient energy landscape.

The above discussion has covered several crucial aspects of grid quality and efficiency in light of the increasing renewable energy supply. As demand-side requirements and variability continue to rise, grid operations are becoming more dynamic, necessitating advanced control and informatics systems to manage grid functioning effectively.

The government, with initiatives like CA, is already devising plans to improve grid quality and planning in response to the growing influence of renewables. The current quality of the grid has been commendable, with tightened frequency variation. As new business models emerge, opportunities will arise for diverse power plant purposes. 

Spokesperson and Quotes –

“Using advanced analytics and AI, utilities boost performance and achieve seamless renewable energy integration.” – Mr. M. Venkatshan, DGM SRLDC, Grid India

“HVDC are key in integrating abundant solar and wind power, facilitating substantial inter-regional power transfer.” – Mr. Vikram Gandotra, Head of Utility Sales & Strategies at Siemens Ltd.

“The lack of thorough policy analysis has led to challenges, such as forced adoption without evaluating efficacy.” – Mr. Baldev Raj Narang, CEO of Clariant Power Systems Ltd.

“Renewables are vital for the future, electrifying hard-to-abate sectors like transportation and industries.” – Mr. Sirish S. Garud, Director-Renewable Energy Technology, TERI.