Gujarat is among the leading states in renewable energy capacity addition. Growing variable generation is leading to issues related to grid stability and reliability in the state. This has resulted in the loss of generation and revenue from wind and solar projects and has thus impacted their viability. A potential solution to this issue is forecasting renewable energy generation and scheduling the same in order to allow better management of the grid.
Recently, the Gujarat Electricity Regulatory Commission (GERC) published draft regulations for forecasting and scheduling for wind and solar projects. Odisha, Madhya Pradesh, Karnataka, Tamil Nadu, Rajasthan, Jharkhand, Andhra Pradesh and Chhattisgarh had earlier come out with similar regulations. So far, Karnataka is the only state that has published final regulations for forecasting and scheduling for wind and solar projects in the country.
These regulations provide the methodology for day-ahead scheduling of wind and solar energy generators that are connected to the state grid, and to reschedule them on an hourly or one-and-a-half-hourly basis. They also have provisions for handling deviations in the actual and scheduled generation of wind and solar energy. To ensure effective implementation, appropriate meters will be provided for energy accounting, along with telemetry/communication systems and data acquisition systems for the transfer of information to the concerned state load despatch centre (SLDC).
The following section provides an overview of the provisions of Gujarat’s forecasting and scheduling regulations.
Following the intra-state forecasting and scheduling regulations for wind and solar projects by the Forum of Regulators (FoR), Gujarat has proposed these regulations for all projects located in the state (including those connected via pooling stations), regardless of their date of commissioning and capacity. These substations are required to provide schedules for a day ahead and three days ahead, and intra-day revisions to a maximum of 16 days for wind and eight days for solar projects. Aggregation of more than one pooling station is allowed under the state regulations. Generators are required to provide supervisory control and data acquisition (SCADA) and telemetry data to the SLDC, which will be used for data or information exchange requirements and protocols for the same.
For smooth functioning of the forecasting and scheduling process, the FoR regulations have defined qualified coordinating agencies (QCAs), which will coordinate on behalf of the wind or solar generators connected to a pooling station. These QCAs will be treated as state nodal agencies (SNAs) under the Gujarat forecasting and scheduling regulations. The QCA may be one of the generators or any other mutually agreed to agency. The agency will be responsible for metering, data collection and transmission and communication, coordination with discoms, SLDCs and other agencies.
While deciding on the deviation settlement, the state has again followed the FoR regulations. As per the regulations, deviation charges will be paid by the buyer as per the actual generation (this is the same as in the case of draft regulations of Tamil Nadu, Madhya Pradesh, Odisha, Rajasthan and Jharkhand). The regulations also take into account the available capacity while calculating the error in the actual generation of wind or solar generators with reference to the scheduled generation for each 15-minute time block. This helps in pushing the generator to keep the total available capacity close to the actual capacity of the project, in order to keep the error as small as possible.
Error = (Actual generation-Scheduled generation)/Available capacity
The deviation slab has been kept at ±12 per cent for old projects and at ±8 per cent for new projects. The reference date for old and new projects has been proposed as January 30, 2010. Appropriate meters will be provided for energy accounting, along with telemetry or communication systems and data acquisition systems for the transfer of information to the Gujarat SLDC by the generator or the QCA appointed for it. However, penalty rates are different from those in the FoR regulations. For wind, the initial penalty rate has been set at Re 0.35 per unit, which increases to Rs 1.05 per unit for higher bands. For solar, the penalty rates have been set in the range of Re 0.60-Rs 1.80 per unit. The schedule of wind and solar generators connected to the state grid (excluding collective transactions) may be revised by giving advance notice to the SLDC. Such revisions will become effective from the fourth time block for wind projects. One revision for each time slot of one and a half hours is allowed, which converts into 16 revisions during a day. Similarly, for solar projects, a total of eight revisions are allowed during a day. Unlike all other deviation settlement mechanism regulations, the absolute error for wind energy generators will be reduced by 1 per cent every year, from the start of the fourth year till the subsequent five years. Following this, at the end of the fifth year, the absolute error will become £ 7 per cent for old wind projects and <=3 per cent for new wind projects. Similarly, in the case of solar projects, the absolute error will be reduced by 1 per cent every year from the start of the fourth year till the subsequent five years, reaching the minimum level of £ 2 per cent.
With the rising share of renewable energy in the state’s electricity supply mix, it has become important to be equipped to deal with the intermittent power generation while maintaining grid stability and reliability. The increasing focus of the regulators on establishing a well-defined framework for forecasting and scheduling is a positive sign in this direction. The effective implementation of these regulations will make investments in wind and solar projects more attractive and stable for investors.
By Meera Bhalla