Renewable energy forecasting is the short-term prediction of generation from renewable power plants, generally on week-ahead, day-ahead, or intraday timescales. With the increasing penetration of renewable energy sources into the electricity grid, accurate forecasting of their generation becomes crucial for efficient grid operation and energy management. It also supports system operators in performing despatch planning, that is, to develop a schedule that balances generation with load while managing appropriate amounts of reserves. The framework for the forecasting and scheduling (F&S) of renewable energy was first introduced in 2014 by the Central Electricity Regulatory Commission (CERC). Since then, the regulations have undergone several amendments and refinements to keep pace with the rapidly evolving renewable energy landscape.
Renewable Watch provides an overview of the regulatory framework governing the F&S of renewables in India…
Role of key entities in F&S
Load despatch centres (LDCs): Regional load despatch centres (RLDCs) are responsible for producing day-ahead or intra-day forecasts and scheduling for renewable generators transmitting power across states while state load despatch centres (SLDCs) perform similar functions at a transmission pooling substation level, dealing with intra-state transactions. All eligible renewable energy plants are required to submit their forecasts to the respective LDCs. Based on these forecasts, the LDC generates schedules or despatches for each renewable energy plant.
Renewable energy generators: They have the option to either use the schedule provided by the LDC for a fee, forecast their generation independently, or acquire forecasts from private forecast service providers. They are allowed to revise their day-ahead forecast or schedule by giving a 60-minute notice, with a maximum of 16 revisions per day.
Renewable energy management centres (REMCs): To enhance forecasting accuracy and situational awareness, 13 REMCs have been established across India. These centres are co-located with the National Load Despatch Centre, RLDCs of renewable energy-rich regions, and SLDCs of renewable energy-rich states. REMCs provide forecasts to RLDCs and SLDCs, leveraging advanced forecasting models and data analytics.
Some other key provisions of the framework include:
- Hybrid approach to forecasting – combination of centralised forecasting by RLDCs and decentralised forecasting by wind and solar generators to minimise forecasting errors.
- Deviation charges linked to power purchase agreement rates.
- Provisions for meeting any shortfall through renewable energy certificates.
- Renewable energy generators can revise the day-ahead forecast/schedule by giving a 60-minute notice. They are permitted a maximum of 16 schedule/forecast revisions each day.
Subsequent amendments and additions to the framework have further refined and strengthened the regulatory landscape. In March 2022, the CERC Deviation Settlement Mechanism (DSM) Regulations, 2022, were notified, repealing the earlier regulations. These new regulations delinked deviation charges from system frequency and linked them to market platform prices, a significant departure from the previous approach.
Under this amendment, wind and solar generators were exempted from any deviation charges for overinjection. In the case of underinjection, they were exempted from charges for up to a deviation of 10 per cent (previously 15 per cent) from the generation schedule.
In February 2023, the CERC issued new guidelines to supplement the DSM Regulations, 2022, with a focus on maintaining grid security. The commission introduced a new category of wind-solar generators and implemented charges for deviation settlement.
Additionally, monetary incentives for both generators and procurers were increased to encourage maintaining grid frequency within the safe range of 49.95-50.05 Hz.
State regulations
The CERC regulations established the framework for interstate generating stations, which was followed by the Forum of Regulators publishing model regulations to be adopted at the state level for renewable energy plants. Based on the model regulations, several states have issued their F&S regulations with different DSM criteria for generators.
While state-level regulations typically align with the central framework, there may be variations and nuances specific to the unique circumstances of each state and renewable energy potential. The following is an overview of the key aspects of state-level regulations:
- F&S requirements: Most states have mandated renewable energy generators to submit day-ahead generation forecasts and schedules to the respective SLDCs. These forecasts are used for despatch planning and commercial settlement.
- Deviation management: State regulations often include provisions for managing deviations from scheduled generation, such as deviation charges, tolerance bands, and penalties for persistent deviations.
- Coordination with central agencies: Some states have established coordination mechanisms with central agencies like REMCs and RLDCs to enhance forecasting accuracy and ensure seamless integration with the national grid.
- Incentives and support mechanisms: Several states have implemented incentives and support mechanisms to encourage the adoption of F&S practices by renewable energy generators. These may include financial incentives, technical assistance, or capacity-building programmes.
Challenges and the way forward
While the regulatory framework for renewable energy F&S in India has made significant strides, several challenges remain that need to be addressed to ensure the successful integration of large-scale renewable energy into the grid.
One of the major challenges is the accurate forecasting of renewable energy generation at the distribution level. This includes all distributed renewable energy resources connected to the distribution network. Central despatchers face significant difficulties in accounting for these distributed resources, as many grid codes and regulations do not require them to register with the system operator or submit forecasts to the despatch centre. For lower levels of distributed renewable energy penetration, the approach of forecasting net load may be acceptable. However, as the penetration of distributed renewables increases, the accuracy of net load forecasting deteriorates without explicitly accounting for renewable generation from all generators on the distribution network.
To address this challenge, it is imperative to develop forecasting models that explicitly account for renewable generation at the distribution level. Furthermore, regulations may need to be updated to mandate the registration of all renewable generation resources, regardless of their size or connection point, to enable accurate forecasting and system-wide visibility.
Accurate forecasting relies heavily on the availability and quality of data, including meteorological data, historical generation data, and real-time operational data. Ensuring the availability of high quality data from renewable energy generators and relevant stakeholders is crucial for improving forecasting accuracy. Initiatives to enhance data collection, standardisation and sharing mechanisms could significantly contribute to enhanced forecasting and scheduling outcomes.
The rapid advancements in data analytics, machine learning and artificial intelligence present opportunities to enhance forecasting techniques. However, the uptake of these advanced technologies is limited due to cost considerations.
Adopting advanced forecasting models that can better capture the complex dynamics of renewable energy generation, account for weather patterns and incorporate real-time data could significantly improve forecast accuracy. To this end, collaborations between academia, research institutions and industry stakeholders could drive innovation in this area.
As the share of renewable energy in the grid continues to grow, the need for grid modernisation and seamless integration becomes paramount. This may involve upgrading grid infrastructure, implementing advanced control systems and enhancing energy storage capabilities to better manage the intermittency and variability of renewable energy sources.
Going forward, periodic reviews and updates of the regulatory framework, both at the central and state levels, are necessary to ensure alignment with technological advancements, market dynamics and evolving industry best practices. Continuous stakeholder engagement, including generators, system operators, regulators and policymakers, is crucial for identifying areas of improvement and facilitating a smooth transition towards a more sustainable and resilient energy system.
