Can the Indian power grid host rooftop solar PV?
Power grids all over the world were originally designed for one-way supply of power from the grid to the end consumers. Solar PV systems, when connected to the grid create a two way supply of power (from the grid to the consumer and vice versa) and multiple power sources. This does not fit the original design of grids and can create operational problems. Moreover, a traditional grid can only accommodate a certain level of PV into its current structure without affecting its power supply. This means that the potential for solar may be vast for a particular country, but issues related to grid connectivity could limit the potential that can actually be exploited.
- Solar PV systems connected to the grid can adversely affect the quality and supply of power, however, most of such connectivity problems have workable solutions
- There is no study that determines the Indian grid’s ability to host solar PV. Studies conducted globally indicate that a grid can accommodate 15-20% PV penetration without destabilizing its power supply.
- With standardized connectivity guidelines in place and with the help of intelligent equipment that regulate power supply, the Indian power grid can accommodate at least 20% of PV penetration.
There are many problems that may be encountered with the integration of solar PV to the Indian grid. When the grid receives power from different power sources (multiple small PV systems) the quality of power can be adversely affected. The grid may also get destabilized when a large number of PV systems get disconnected from the grid at the same time because of voltage fluctuations. Further, cloud cover and rain can adversely affect the capacity of PV systems to produce energy at a given point of time and this may create problems for the grid operator in managing the power supply of the grid. Most of these problems, however, have feasible solutions. Simple standards for equipment and guidelines for connectivity can ensure that power supply and its quality are not affected. In fact, if done right, the integration of PV systems could also stabilize the grid. The Central Electricity Authority (CEA) is currently working on a report that specifies such standards for grid connectivity. Further, the intermittent power supply of solar PV systems can also be managed by better weather forecasting and load (power demand-supply) management.
The number of solar PV systems that can be connected to the grid without affecting the current functioning of the grid still remains uncertain. There has been no detailed study on the ability of the Indian grid to handle distributed, intermittent power sources such as PV systems. Even in countries such as Germany or the US, where studies have been conducted, there is no clear indication of what a grid of specific characteristics can handle. Several studies indicate that PV systems can power 15% of the peak load without affecting a grid’s existing supply structure. But with a number of countries already reaching 15% PV penetration levels, this thumb rule is being considered for revision in many parts of the world, such as in the US. Many studies have also concluded that the grid has the capacity to tolerate much higher PV penetration levels, provided considerable investments are made in equipment like intelligent transformers, storage devices that regulate the quality of power and stabilize the grid and advanced ‘smart’ grid management solutions. With the help of such solutions countries like Germany have managed 40% PV penetration on their grid.
Currently, in India, solar power has a very small share (<1%) in the overall energy mix, although the percentage will be substantially higher in parts of Gujarat and Rajasthan. With only a limited amount of PV on the grid, PV penetration is not actively discussed in India at the moment. But given that 15% is considered to be a safe and perhaps overly conservative number, we believe that India’s power grid can accommodate at least 20% of PV penetration without requiring major investments in additional infrastructure. However, a detailed study of the grid infrastructure would be required. Pilot projects to understand the PV hosting ability of the grid network would be essential as well.
India is at a stage where a large part of the grid is either being created or being re-vamped. This is the right time for India to learn and adapt. India should follow the example of countries like the US and Germany to understand how the grid’s capacity to host solar can be increased. Such countries have been working towards the adoption of solar for years now and thus have a better understanding of the complexities of the traditional grid and advanced technologies that can facilitate the integration of solar.
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