Under the panchamrit pledges made at the COP-26, India pledged to put in place 500 GW of non-fossil fuel-based capacity by 2030. As the installed Renewable Energy (RE) capacity in the country increases, the amount of intermittent renewable energy flowing through the grid will also go up. A very high share of solar and wind power at an instant in the grid poses several challenges. The locations of the variable energy resources (VRE) are diverse and major solar power parks are far away from the existing grid facilities. This requires the development of a robust grid system right from scratch.
The communication networks are also not easily available in remote locations. Geographical locations of VRE thus offers advantages at some locations, whereas the other locations are not so favourable.
The gestation period of solar and wind power generating facilities ranges between 18-24 months, whereas the transmission system establishment often takes more time, posing constraints in the evacuation of RE power. Various policy and strategy measures are being taken to overcome this situation. Further, Right of Way (RoW) issue is also quite challenging. Forest clearances are another important aspect which needs to be tackled.
Transmission system development requires meticulous planning, various studies, design, engineering and construction in difficult terrain (sometimes the climate/weather conditions do not permit the execution of works, thus there are limited months of the year in which construction can be undertaken). Therefore, there is a need to develop an adequate capacity downstream system so that power evacuation and power absorption are seamless. In remote locations, there have been instances of theft of material, thus putting hurdles in the way of the establishment of the power transmission network.
In addition, there is a lack of reliable long-term demand projections and forecasts at the state level. Proper forecasting and scheduling of RE resources is a prime requirement of system integration. There is a lot of scope for improvement in this area. To tackle the issue of gathering real-time data from RE generation resources, Renewable Energy Management Centres (co-located with load dispatch centres) have been set up that manage solar and wind power capacity and share data among state, regional and national grid operation centres.
There is potential for growth in India and the domestic demand is also on the rise. Increasing peak demand is being driven by new demand sources such as air conditioners and Electric Vehicles (EVs), green hydrogen production facilities etc. The digital revolution underway in the country (digitalisation of the education system and economy) will further drive a rise in demand. In the area of clean cooking as well, electricity would be playing a major role.
The VRE sources require fast ramp up and ramp down of the existing service resources, thus ramping requirements are increasing, and for existing coal generation plants, there is a lack of flexibility. Adequate retrofitting of control systems, installation of new systems, development of standard operating procedures, capacity building, more automation, system visibility etc need to be done.
The current and future curtailment of solar and wind is both a challenge and a solution for managing the system in emergency situations. While solar and wind have must-run status in most states, this can be secondary to the priority given to hydropower or coal generators in some states at certain times.
Concerns regarding distributed energy resources, such as rooftop solar and EVs, include local voltage issues, reverse flows, lack of visibility of existing and new installations, and challenges with forecasting. Other technical challenges include declining system strength, increasing fluctuations in frequency and voltage levels in certain regions, and the slight decline of inertia in India in recent years.
There is a lack of co-ordination among state-level transmission planners and central planning agencies such as the Central Transmission Utility of India. A unified planning model across the country is the need of the hour. The electricity demand forecasting needs to improve. At the micro level, the specific points of load growth need to be identified. Fault levels are increasing and requisite measures need to be taken.
Policy and regulatory support, plus financial compensation models, need to be developed for developers as well as the users of electricity to encourage them to take part in managing the variable resources and grid successfully.
The development of VRE needs investment, similarly the development of transmission assets needs assets — over all there is a lesser utilisation of these transmission assets, thus the investment needs to be remunerative. Certain incentives will further be required for the effective development of transmission assets and establishment of RE power generation resources.
Emission reduction is one of the biggest advantages of RE sources, and this is the requirement of the energy mix as well. A balance needs to be maintained so that we move towards the path of energy transition. By all standards, making a reasonable investment in developing the low-emission pathway of energy is necessary, and this investment is also desirable as we will be reaping the benefits of low-carbon path development.
Flexibility options are key to integrating renewables and are an integral part of the clean energy transition. The development of the smart grid, the adoption of modern communication, control and automation are the key to managing the system. We need a diverse energy mix, and the sources which have remained untapped so far, like wave, geothermal, ocean energy, waste-to-energy, etc need to be promoted. We have to work on SF6-free alternatives as well as SF6 has 25,200 times global warming potential as compared to CO2, and it remains in the atmosphere for 3,200 years. So it is time that we take steps towards selecting SF6-free alternatives. Avoiding curtailment is a straightforward case, whereby flexibility options allow a higher amount of renewable generation to be utilised, thereby reducing emissions.
The demand management on the consumers’ side can be achieved by suitably devising an incentive mechanism. Consumer participation is a must in the demand response programme. It requires extensive consumer survey and participation of consumers in the demand response programme. The demand response programme could be successful when the consumer is assured that the power will be available to him when it is needed. There may be a need for the installation of smart devices to manage the consumer load. Measurement and verification of the gains is a must to participate in any of utility-driven programme. The programme philosophy and implementation should be simple, easy to understand and easier to adopt and maintain.
The best practices and experiences in this area need to be shared. Specific programmes should be devised in different pockets instead of a one-size-fits-all. Capacity building of employees and spreading awareness among consumers is a good initiative, which should be taken up immediately.
In case of India, we have got the advantage that some of the load types (eg irrigation loads, heating and cooling loads, ice factories load, etc) can be grouped into what is called as essential load as well as non-essential load, and when the system demands they could be appropriately subjected to load control.
Rooftop solar system, wherever feasible, needs to be encouraged. It reduces the burden on the main grid, leaving sufficient margin in the main grid to supply the bulk load and meet the requirement of load centres. Local generation feeding electricity in the local network is also helpful in reducing losses, thus reducing emissions as well. Plus, it provides job opportunities at local levels.
Author is the current Member (Power systems) at the Central Electricity Authority (CEA), Views Expressed in the article are his own.
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