With the growing need for sustainable energy solutions to achieve net-zero emissions by 2070, rooftop solar is becoming an integral part of India’s energy landscape. The launch of the PM Surya Ghar: Muft Bijli Yojana has driven a surge in rooftop solar installations. This programme, with an allocated budget of Rs 750 billion until 2025-26, offers up to 300 units of free electricity per month to 10 million households nationwide. Within a month of its February 2024 introduction, the scheme recorded over 10 million registrations. By December 2024, the initiative had facilitated 630,000 rooftop solar installations, averaging approximately 70,000 installations per month. Projections indicate that installations will exceed 1 million by March 2025 and could potentially reach the 10 million target by 2027. Complementing this national programme, several states have implemented their own policies to support India’s transition to a more sustainable and greener energy future.
Rooftop solar primarily generates power during the daytime, meeting local load demand and exporting surplus to the grid. This reduces the load on centralised generation systems while enhancing localised power availability. Rooftop solar systems, when synchronised with the grid, support voltage regulation and reduce transmission losses by generating power close to consumption points. However, the integration of the solar power system into a distribution power grid can impact grid voltage. Solar PV systems can significantly increase voltage at some nodes, leading to overvoltage near the solar power source. While large-scale adoption may cause localised voltage fluctuations, these challenges can be prevented through advanced inverters with reactive power control.
Key challenges
As rooftop solar installations expand, concerns about power quality, such as brownouts, voltage fluctuations and harmonics, are becoming increasingly prevalent. The output of a solar panel is always fluctuating. This output goes through an inverter in order to convert the DC to AC. An unconditioned AC voltage can create many power quality issues.
Intermittency is a big challenge. Solar power varies with sunlight availability. This can lead to fluctuations in power output, potentially affecting power quality if not managed properly. In India, where peak electricity demand often coincides with evening hours when solar generation is low, integrating solar power into the grid requires careful planning and management.
Voltage unbalance is another critical issue. If a solar array is not connected to the phases, it can cause unbalanced voltage conditions. The more single-phase solar arrays connected to the grid, the worse the problem becomes.
It is also difficult for utilities to monitor the quality of electricity generated from PV systems because of the diverse nature of grid-connected inverters. Inverters from different manufacturers have varying levels of stability. The quality of inverters also remains an issue. High quality inverters provide cleaner, more stable power, while poor quality inverters can introduce harmonics and noise. The use of high quality, certified inverters is essential for maintaining power quality.
If the solar system does not have proper voltage conditioning, high-speed transients may be created, which can have adverse impacts on residential and commercial electronics.
Also, medium and low voltage distribution transformers often have fixed voltage taps. Their mode of operation, combined with the operation of reactive power compensation capacitor banks at load points, faces significant risks when integrated with rooftop solar power systems.
Outlook
When properly installed and managed, rooftop solar systems typically improve the overall quality of power. Most modern systems include features that mitigate potential negative impacts, such as sophisticated inverter technology and grid-tied systems that ensure seamless integration with the main power supply. Regular inverter checks, panel maintenance and professional inspections are essential for maintaining optimal performance.
Rooftop solar provides a compelling solution for clean, renewable energy in India. Residential and commercial locations that utilise solar systems can serve as either a load or a source, depending on whether they are drawing power from the grid or supplying power to the grid. This means the power flow reverses direction. This bidirectional flow creates challenges for utilities, particularly in setting proper voltage levels, which require utilities to adjust tap settings on their transformers.
Beyond economic and environmental benefits, rooftop solar has the potential to significantly improve the quality of power. Understanding both its advantages and challenges enables informed decisions to harness this technology’s full potential. As India continues its solar journey, the role of rooftop solar in enhancing power quality will become increasingly important, contributing to a more stable and efficient energy future. Advanced inverters with better grid support capabilities, including more advanced reactive power support and harmonic filtering, will help integrate solar power more seamlessly into the grid, improving overall power quality. Continued government incentives and regulatory support will be crucial for promoting rooftop solar adoption and ensuring consistent, high-power delivery.
