The world is moving towards a future without fossil fuels, and this transformation is already underway. Fossil fuels, which have been the main source of energy for more than a century, are in decline for reasons of both environmental sustainability and limited availability1.

The PNIEC (National Integrated Energy and Climate Plan 2021-2030) stipulates that by 2030, 42% of the final energy consumed must come from renewable sources. To reach this objective, 27% of this final energy must be electricity, mostly generated from renewable sources (with a goal of 74%). This will involve the installation of more than 55GW of additional renewable generation capacity. This increase in the share of renewables in our energy mix raises new technical issues, as renewables, by their nature, are intermittent and less predictable compared to traditional energy sources. This can lead to inestabilities in the electricity grid, manifesting themselves as congestion and voltage variations.

On the demand side, the energy transition will also require an increase in the electrification of energy consumption, especially in the transport and air conditioning sectors, as well as in some industrial demands.

For the electric system, this will result in an increase in electricity demand and a transition from a traditional, flexible and highly predictable centralised generation system, with passive consumers and distribution networks, to predominantly renewable, decentralised and intermittent generation system, with managable demand resources and an increasing need for flexibility to ensure efficient levels of quality and safety..

The flexibility of a power system is defined by its ability to adapt to imbalances between generated and consumed power. Failure to meet this condition can lead to system and, therefore, on the supply. Till today, the flexibility of our system has being mainly proportionated by fossil generation plants, that equilibrates the generation of existent demand, maintaining a controlled growth of the electric demand. However, at the energy transition context, this change for several reasons:

  • The main renewable generation sources (solar and wind) do not have the capacity to “keep up” with demand.

  • When the transmission capacity of power lines is exceeded by demand, congestion arises, leading to overloads and supply failures.

  • When the quantity of power generated doesn´t match the real-time demand, voltage variations occur, affecting the quality of the power supply and potentially damaging equipment and appliances connected to the grid.

  • The electrification process entails a significant increase in consumption on transmission and distribution lines, which must be adapted to this increase in demand, especially during consumption peaks. Adapting these infrastructures exclusively through the repowering of lines or the installation of additional lines would have a very high material and economi cost.

  • The current model of renewable energy integration is associated with more decentralised generation, wich means that flexibility suppliers will also be increasingly distributed across distribution networks.

  • Although electricity storage offers high system flexibility, its high cost, especially in pre-metered systems, makes it necessary to consider additional sources of demand flexibility.

For all of these reasons, it is considered critical to favour and promote demand flexibility. This can be done implicitly, through incentives for users to change their consumption habits, for example, price signals, and also explicitly, where the activation of flexibility is direct and with a shorter-term response. An example of this second case is balancing services.

On the other hand, grid instability, resulting from the high share of renewables in a decentralised scheme, can be addressed through participation in local flexibility markets, which allow consumers and small generators to offer consumption and generation adjustment services, helping to stabilise the grid.

In the ENFLATE project, CARTIF is developing a flexibility management tool that helps the network operator to manage distribution networks by simulating scenarios representing participation in local flexibility markets. In is also possible to simulate the provision of balancing services for the transmission grid operator. These services are studied on the electricity netowrk of Láchar (Granada), operated by the partner CUERVA.

In Spain there is still no regulatory framework for local flexibility markets, so the European framework is used. The minimum size of flexibility offered in the local flexibility markets considered in the ENFLATE project is of 0.1MWh and the trading period is one hour. The two products offered are: surge management and congestion management.

Balancing services are offered in the balancing markets. There are three possible services: primary regulation, secondary regulation and tertiary regulation. In ENFLATE we simulate the last one, also known as manual actuation reserve for frequency. It allows offering 1MW to be bid and the trading period is from 15 minutes to two hours.

ADAION is another partner providing digitisation services on the demonstrator. Its cloud-based platform uses artificial intelligence to simulate and know the capacity of the network at all times. It provides the necessary inputs to the algorithm developed by CARTIF, so that participation in both markets can be simulated. Renewable generation, flexible demand and electric storage.

Thanks to projects such as ENFLATE, we can study the scope and benefits of using demand flexibility in real demonstrators such as the Láchar grid, simulating flexibility and balancing market conditions. In this way, we prepare for the challenges of the energy transition. At national level, the current regulatory framework for demand-side flexibility is underdeveloped and scatteres in various regulations, which have gradually been modified with the aim of transposing the European Directives. While they are being consolidated, we preparing for change with projects financed by the European Commission, as in the case of ENFLATE2.


1 https://www.bbvaopenmind.com/ciencia/medioambiente/prescindir-los-combustibles-fosiles/

2 Project funding by the Horizon Europe programme of the European Union. Grant agreement: 101075783

María Ángeles Gallego de Santiago
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