Having an accurate forecasting model to calculate available energy generation is essential for optimal supply coverage and to ensure the security and proper functioning of the transmission grid. This process involves analysing the availability of resources from the immediate present to the long term. It is also necessary to take into account the expected demand levels for the various time frames. At Red Eléctrica, the System Operation Modelling department is in charge of making these forecasts.

It is important to note that generation and demand forecasts significantly affect the company's high-impact activities, such as guaranteeing the customers' electricity supply, ensuring appropriate planning of the transmission grid or explaining studies on electricity demand coverage to stakeholders. Additionally, in the current context of energy transition and changes in the climate, the company considers the constant improvement and updating of forecasting systems to be a priority in order to ensure the stability and operational quality of the electricity system.

In line with this purpose, the System Operation Modelling department has launched the Project for the Standardisation of Forecasting Models in collaboration with the Association for the Development of Knowledge Engineering (ADIC) and Elewit. The main purpose of this project is to harmonise the forecasting models and methodologies used for the various processes and to conduct research to improve the different forecasting models and their implementation in order to better adapt to the current and future challenges of the energy sector. Among other lines of research, the latest work addressed three important points:

• The effect of constraints.
• The impact of unavailability.
• The effect that changes in the grid have on prices.

Constraints are restrictions that are imposed by the grid itself, these are required in order to guarantee the correct operation of the electricity grid and to minimise the risk of interruptions in demand, thus avoiding interruptions in supply. Unavailability refers to external situations that make energy resources unavailable for a period of time.

As for the impact on prices, it is useful to study variations because they are partly based on the generation mix that covers demand, and calculating the price is more complex when it depends on the availability of variable resources such as the sun or wind, as opposed to coal or gas. For example, if electricity prices are forecast assuming a large contribution from wind generation, but a sudden variation in pressure causes the wind to stop, this resource would have to be replaced by another that does not jeopardise supply and may have a different price.

For this reason, a revised model for forecasting solar energy generation and the allocation of balancing energy are two of the main points of the project on which work is still ongoing. The latter refers to the markets and investments carried out by Red Eléctrica to ensure that generation meets demand in order to maintain optimum supply conditions.

However, although the project is still active, a major part of its goals have already been achieved, including:

• Optimisation and automation of forecasting processes in the medium and long term.
• Improved calculation of the variables related to the energy transition, readjusting the parameters and configuration of previous models.
• Study of the seasonal predictability of demand in the medium term, the results of which will be implemented in the forecasting model.
• Analysis of the maximum wind energy generation capacity according to weather forecasts.

Last but not least, another variable that needs to be taken into account to improve the efficiency of our forecasting models over medium and long-term periods are the socio-economic indicators. These are important because variations in GDP, the unemployment rate and inflation, among others, have a nationwide impact on the electricity demand from sectors such as industry and services, as well as the general population, whose energy and electricity requirements are changing significantly in response to changes in the country's productive structure and the energy transition itself, which is leading to increasingly active demand behaviour.

Completion of the project is scheduled for the coming months, with the aim of implementing the improvements identified to provide a more efficient and stable service.