MARES Real Time Automatic Control for PSH in Small Isolated Systems




Red Eléctrica de España


Red Eléctrica de España (REE)’s tool MARES is a real time monitoring tool based on automation algorithms developed in order to maximise the penetration of renewables while assuring the security of supply in an isolated system on the island El Hierro.


  • Maximises the amount of renewable energy that the is able to be fed into the El Hierro power system in a system-safe way
  • Minimises the risks associated with unpredictability of wind-power that could trigger important incidents in the power grid and island-wide blackouts
  • Develops a self-made automatised solution that suits the challenges faced by the island
  • In 2019, renewables met 54% of the island's total electricity demand, thanks in part to the Gorona del Viento wind power-based pumped-hydro system which pushed the figure close to 100% in July 2019.

Main information:

The island of El Hierro supplies part of its demand out of a unique power plant - a wind park linked to a pumped hydro storage system. The wind power is fed in when available. In times of oversupply water is moved to a storage reservoir in order to be used to generate electricity on demand.

The software tool MARES is employed to monitor this interaction, optimise the management process performed by the operator and minimise the response time. The ‘Real-Time Automatic Management’ tool is based on the idea that automation, real-time monitoring and fast-response are key to achieving the integration of high shares of renewables in a frail, isolated power system. As a result, the integration of renewable energy has moved from 2% in 2014 to currently over 20% on average, and even reached a peak of 50% in February 2016 when a continuous 40-hour period with 100% renewable demand coverage was reached. The generated renewable energy replaces electricity traditionally produced by diesel generators.

During the development phase of the project, the “test-bed” was the power system itself. Since the implementation no major grid discrepancy occurred. Dispatchers at the control centre are evaluating the tool performance continuously, providing feedback and enhancement proposals.

Further benefits have been identified beyond the increase of renewable penetration: the optimisation of dispatchers’ daily tasks, a cleaner environment, a reduction of system costs and an increase in tourism.

Additional information:

Red Eléctrica de España (REE) is the Spanish transmission operator. REE connects 45 million people with electricity, aided by a workforce of 1,700 people. Its mission is to guarantee the correct functioning of the electricity system at all time.

RGI gratefully acknowledges the EU LIFE funding support:

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Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the LIFE Programme. Neither the European Union nor the granting authority can be held responsible for them.