In an exclusive interview, Rashmi Kumari of NSH delves into the inspiring journey of Dr. Godugunur Giridhar, a byname of innovation and sustainability in the renewable energy sector. Serving as the Director at Pashar Solar Private Limited, Dr. Giridhar has been instrumental in advancing solar energy in India. With a deep-seated commitment to the National Solar Mission, his work encompasses enhancing solar power generation and spearheading research in solar resource assessment. Dr. Giridhar shares insights from his pioneering contributions to solar energy, his vision for a sustainable tomorrow, and the role of technology in overcoming the challenges of renewable energy.
Your research has extensively focused on the impact assessment of short term variability of solar radiation in India. What are the key findings or implications of this research for the renewable energy sector in India?
With the introduction of the National Solar Mission by the Indian government, the utilization of renewable energy sources, particularly solar and wind energy, has seen a significant increase. However, the implementation of this program presents several challenges, primarily because the generation of energy from these renewable sources is subject to the unpredictability of nature.
It is crucial for individuals and officials involved in this sector to understand how weather variations can impact energy production and devise strategies to mitigate these effects. For instance, the generation of power can fluctuate due to a sudden decrease in solar energy caused by passing clouds or a drop in wind speeds. These fluctuations pose questions that directly affect grid management.
To address these issues, this project was initiated, focusing primarily on solar projects. This is in line with the core topic of discussion – the National Solar Mission.
Your work on the development and testing of gap filling procedures for solar radiation data in India is quite intriguing. How do these procedures contribute to enhancing the accuracy and reliability of solar energy resource assessments?
In response to the Indian central government’s National Solar Mission, a critical question arose regarding the potential of solar energy across the country. To address this, we initiated the establishment of a comprehensive solar radiation network. This network comprises 121 fully automated measuring stations, strategically distributed nationwide, ensuring minimal human intervention is required for their operation. This network is unparalleled globally in its scale and density, with a station placed every 200 kilometers, offering a granular view of solar radiation data across various regions.
These stations are equipped to autonomously record weather and solar parameters every second, with the collected data promptly transmitted to a central server hosted by the National Institute of Wind Energy in Chennai. This real-time data collection and analysis serve as the backbone for our solar radiation map, which significantly aids in identifying potential sites for solar farm development and informs policymakers about the viability and strategic locations for solar energy production.
However, the process of data collection is not without its challenges. Instrument malfunctions, maintenance issues, or communication breakdowns can lead to data loss, sometimes spanning a few minutes or even hours. To combat this, we employ a sophisticated gap-filling technique. This method utilizes a statistical analysis of historical data spanning a century to predict and fill in the missing data, ensuring that developers, government officials, and policymakers have access to complete and accurate information. This approach not only compensates for the inherent limitations of ground measurements but also reinforces the reliability of the data used for advancing solar energy projects and policy formulation in India.
The feasibility studies on virtual power plant in India that you have been involved in are critical for the future of energy systems. What are the main challenges and opportunities you have encountered in this field?
The concept of a Virtual Power Plant (VPP) is indeed critical for the future of energy systems, particularly in a country like India with its diverse energy sources. The primary idea behind a VPP is to ensure a consistent power supply to the grid around the clock.
Given the nature of renewable energy sources, such as solar energy that operates only during the day and wind energy that can fluctuate, it’s crucial to have a backup energy supply to ensure that the grid is powered 100% of the time. To achieve this, energy from various sources – solar, grid, hydro, and wind – is pooled and automatically controlled to meet the power requirements of the grid or the customers.
This concept, while new to India, is widely used in many developed nations, particularly in Europe. However, during my tenure, I was unable to complete the implementation of this demo project. Despite this, the concept holds significant potential for ensuring grid stability in India, which is crucial for the country’s energy future.
The main challenges encountered in this field primarily revolve around the inherent unpredictability of renewable energy sources and the technical complexities involved in pooling and automatically controlling energy from various sources. On the other hand, the opportunities are vast, given the increasing focus on renewable energy and the need for grid stability in the face of growing energy demands.
Your research emphasizes the importance of accurate solar resource assessment and mapping in India. How do you foresee these efforts impacting the growth and implementation of solar energy technologies in the country?
Solar resource assessment and mapping are indeed pivotal in the growth and implementation of solar energy technologies in India. Solar mapping is particularly useful for micro-siting, a process that identifies suitable locations for setting up solar power plants.
India is blessed with an abundance of solar energy. However, it’s not feasible to harness solar energy everywhere due to factors such as human habitation, forest areas, wastelands, water bodies, protected areas, and defense areas. These areas need to be excluded when considering locations for solar power plants.
Solar mapping serves as the first step for a developer to determine whether a particular site is suitable for a solar power plant. For instance, if a developer identifies a potential site, say Village A, they can use solar mapping to determine whether the site is a forest area, water body, or a restricted area.
Once the site is identified, the developer can then ascertain the available infrastructure facilities, such as power evacuation, grid connection, and grid evacuation. They can also determine how to export the generated power to the nearby substation, the capacity of the substation, and the type of solar power plant that can be set up, whether it’s a concentrated solar power plant or a solar PV-based power plant.
All these factors can be visualized using a solar map. This not only aids in site selection but also helps developers theoretically estimate the amount of solar energy that can be generated in a particular area. Therefore, accurate solar resource assessment and mapping are instrumental in advancing solar energy technologies in India.
How do the Google Maps aid your solar resource mapping?
Google Maps plays a significant role in aiding solar resource mapping. Initially, we use Google Maps for the mapping process, and then we add various layers to it, such as forest areas, defense areas, roads, buildings, agricultural fields, villages, inhabited areas, and more. On top of these layers, we overlay the solar radiation data.
Solar radiation comprises three components: direct radiation, global radiation, and diffuse radiation. For our solar power plants, we primarily require global radiation and direct radiation. Our efforts in creating this map will indicate the content of global radiation and direct radiation in these areas.
For instance, static solar panels, i.e., solar PV panels that do not move, generally require global radiation. However, there are technologies where the solar panels move along with the sun. These are known as concentrated solar power plants, which track the sun, capture the direct radiation, concentrate it in a particular place, and then generate energy. For this, we require more of direct radiation.
Direct radiation is predominantly available in less polluted areas and hilly areas like Leh Ladakh, which have high direct radiation concentration. In contrast, cities and nearby villages have more of global radiation. Depending on the type of component that is more available – be it diffuse radiation, global radiation, or direct radiation – we can design the technology accordingly. This solar mapping thus aids in the selection of suitable technologies.
What role do the contour lines play in this process?
Contour lines play a significant role in the process of solar resource mapping. They are particularly useful in the layout of solar panels and for conducting shadow analysis.
If there are high-rise buildings, mountains, or a large number of trees, contour maps can help identify and avoid shadow areas. This is crucial because shadow-free areas are required for all solar applications.
Your involvement in the operation of solar radiation resource assessment stations in India is remarkable. Could you elaborate on the significant contributions of this network in improving solar energy forecasting and planning?
Solar forecasting is indeed a distinct yet crucial aspect of the operation of solar radiation resource assessment stations in India. It plays a vital role in grid management, as it allows grid operators to anticipate the amount of solar energy that will be available in the next 15 minutes. This information is essential for meeting the power requirements of cities, towns, and industries.
For instance, consider a 100-megawatt solar farm. This farm contributes a certain amount of power to the grid, which allows electricity boards or power grid operators to reduce their reliance on other sources such as hydro or atomic energy. However, due to factors like passing clouds, rainy seasons, or other reasons that could cause a breakdown in the solar power plant or a sudden drop in power generation, the power grid operator needs to quickly calculate how much power they should draw from other sources to ensure smooth grid management.
Recognizing the importance of this, the Government of India, under the Central Electricity Authority and Power Grid Corporation, has made it mandatory for solar developers to provide a forecast every 15 minutes of how much energy is going to be supplied to the grid. If there is any deviation from this forecast beyond certain limits, the developers are penalized.
The data we measure from the ground helps us in making these forecasts. It involves a lot of work, including analyzing ground data, measured data, and satellite data to come up with the forecast. Once the solar forecasting is known, we can determine the channel capacities, their efficiencies, and energy generation based on the solar data. We can then calculate the power generation and regularly feed this data to the State Load Dispatch Centers (SLDCs), which manage the grid. This solar forecasting thus aids the SLDCs in managing the grid effectively, making this data a basic requirement.
What are the key factors and considerations for assessing solar resources of a concentrated concentrated solar power CSP projects in India based on your research findings?
In our exploration of the potential for concentrated solar power (CSP) projects in India, several key factors and considerations emerge, particularly due to the unique operating principles of CSP technology. CSP plants harness direct sunlight, concentrating it onto a focal point much like a child might use a magnifying lens to focus the sun’s rays to ignite paper or cotton. This technology employs parabolic or linear parabolic systems equipped with vast mirrors that track the sun’s position via GPS to concentrate sunlight at a point where steam or heat is generated. This steam then powers the generation of electricity.
One of the principal challenges in implementing CSP technology is its sensitivity to atmospheric conditions, especially pollution. In areas with high pollution levels, solar radiation becomes dispersed, reducing the efficiency of sunlight concentration. Consequently, CSP technology is less suited to urban or densely populated areas where air pollution is more prevalent. Instead, its application is more viable in locations with minimal pollution and high solar irradiance.
Regions such as the high altitudes of Ladakh exemplify ideal conditions for CSP plants. Despite the extreme cold, the intensity of solar radiation in these areas is remarkably high, leading to phenomena such as simultaneous sunburns and frostbite among soldiers stationed there. The high solar irradiance, coupled with low pollution levels, makes such locations prime candidates for the deployment of CSP technology.
Moreover, CSP offers a significant advantage in energy storage compared to other renewable sources. The generated steam or thermal energy can be stored efficiently for later use, particularly during nighttime operations. This storage capability not only enhances the utility of CSP plants but also addresses one of the critical challenges in renewable energy: ensuring a stable and continuous power supply regardless of daylight availability. This aspect of CSP technology presents a compelling case for its adoption in regions within India that meet the specific environmental and atmospheric criteria conducive to its operation.
Your collaborative work on creating a new solar atlas and the combined mapping and monitoring approach for solar energy in India is quite impactful. What are the essential elements in creating such a comprehensive solar resource data for the country?
The creation of a new solar atlas and the pioneering approach to solar energy mapping and monitoring in India are central to enhancing the country’s renewable energy infrastructure. This comprehensive endeavor was realized through a notable collaboration with a German government organization, which generously extended its technical expertise and support, enabling the development of advanced solar forecasting technologies.
The project, spearheaded by the National Institute of Wind Energy and generously funded by the Ministry of New and Renewable Energy, Government of India, represents a significant stride in renewable energy research and development. The partnership with German experts facilitated not only the creation of the solar atlas but also contributed to the establishment of one of the largest solar radiation networks across India. This collaboration marks a remarkable achievement in India’s renewable energy landscape, bringing the country’s solar radiation data collection to a global standard.
A pivotal milestone of this initiative was the inclusion of four Indian stations into the Baseline Surface Radiation Network (BSRN), a global consortium of 64 stations dedicated to environmental impact studies through data exchange. Achieving this level of recognition underscores the quality and global relevance of India’s solar radiation data, now traceable to the World Meteorological Organization (WMO) standards.
The solar atlas itself goes beyond traditional mapping; it meticulously delineates various geographical and infrastructural elements crucial for solar project development. This includes the differentiation of land use areas such as forests, water bodies, and agricultural lands, and importantly, integrates vital information for solar developers regarding accessibility to roads, proximity to power grids, and the capacity of nearby substations.
This rich dataset within the solar atlas is designed to facilitate micro-siting for solar projects, offering developers a comprehensive view of potential sites without the need for physical site visits. By providing a digital overview accessible even via mobile devices, the atlas significantly streamlines the preliminary stages of project planning.
Before my retirement, we aimed to enrich the atlas further by adding more layers of data, enhancing its utility for future solar energy projects. The contributions and publications stemming from this work are a testament to the collaborative efforts and innovative approaches that have significantly advanced solar energy assessment and mapping in India, laying a robust foundation for the nation’s renewable energy future.
Your numerous publications and contributions on solar energy assessment and mapping are commendable. Could you discuss the potential implications of your work for policy making and regularity frameworks in India’s renewable energy sector?
The implications of our work on solar energy assessment and mapping extend deeply into policymaking and regulatory frameworks within India’s renewable energy sector. Our solar atlas and related findings offer a nuanced understanding of solar radiation distribution across the country, which is vital for informed decision-making in renewable energy policy and development.
A critical aspect of this work is its potential to guide equitable and efficient solar energy deployment. For instance, areas with lower solar radiation might see the same level of investment as high-potential zones but yield lesser output. Recognizing this, policymakers can develop differentiated pricing models based on the geographic variability in solar generation potential. Such a strategy ensures that investments in solar energy remain attractive across diverse regions, aligning with the Government of India’s broader goal of nationwide renewable energy development.
Moreover, our research can help the government pinpoint optimal sites for solar farming. By identifying these potential sites, the government could streamline the development process through a single-window clearance system, thereby reducing bureaucratic hurdles for solar developers. This approach would encompass not just the installation of solar panels but also the necessary infrastructure support, such as power evacuation, substations, and cabling, further incentivized by land development initiatives to prepare sites for immediate use.
Policy implications also include the possibility of adopting differential pricing for solar power based on generation efficiency. In regions where solar output is high, the cost of solar electricity could be lower, whereas areas with less solar potential might see higher prices to offset lower generation capacities. Such differential pricing could encourage solar development in less favorable regions by making it financially viable.
Additionally, the concept of virtual power plants and hybrid systems represents an innovative direction for policy development. By combining solar with other renewable sources, like wind energy, in areas with complementary potential, India can move towards achieving a 24-hour renewable power supply. This approach necessitates the design of flexible substations capable of handling both solar and wind energy outputs.
In essence, our contributions to solar energy assessment and mapping are not just academic but have profound implications for shaping the future of renewable energy policy in India. By providing detailed, location-specific solar resource data, we empower policymakers to craft nuanced, effective strategies that cater to the unique energy landscape of India, facilitating a more sustainable and inclusive energy future.