In its latest announcement, Acciona Energia says it now allocates 2,000 MW of wind power capacity to provide adjustment services to the electric power system in Spain. As reported, this represents a new technological milestone in terms of the full participation of renewable energy sources in the system and their ability to attain high levels of penetration in it.
The accreditation, which requires renewables to pass the same tests as conventional sources, is issued by Red Eléctrica de España (REE) as the technical operator of the system in Spain and the body responsible for its operation under optimal quality and security conditions.
Acciona says the so-called “adjustment services” – also known as ancillary or balance services – are there to ensure the constant balance between power generation and demand, and they are remunerated. This balance is essential, given that all the electricity produced at a given time has to be consumed at that moment. If not corrected in time, any decoupling between supply and demand could jeopardize the quality of the electricity supply.
Less than a year ago, Acciona achieved a milestone in this area by becoming the first company in the world to provide adjustment services only by increasing generation from wind power, in a field exclusively reserved for conventional energies until recently.
Last Feb. 28, a number of wind farms operated by Acciona increased their output by more than 50 MW in response to an instruction from the system operator. At the time, the company had accreditation for 1,000 MW, and a further 1,000 MW have now been accredited. These 2,000 MW represent 42% of Acciona’s wind power capacity in the Spanish market.
The company’s objective is to reach 3,500 MW of wind-based capacity to participate in adjustment services: technical restrictions markets, tertiary control and management of deviations, plus a certain capacity for secondary control still pending award.
The participation of non-hydropower renewables in the system has been legally possible since last February as a result of the application of a resolution dated Dec. 18, 2015, by the Secretary of State for Energy establishing the criteria for this participation.
Traditionally, adjustment services have been provided by conventional technologies, such as thermal power stations or large-scale hydropower instalations. However, the technological evolution of renewables, together with the development of more sophisticated forecasting and management tools, has opened the door to their inclusion in these markets.
According to the company, Acciona uses the latest technology, both in the management of energy – which it carries out through its subsidiary Acciona Green Energy Developments – and in the remote control of its generation facilities, undertaken by its Renewable Energy Control Center (CECOER) in constant coordination with REE.
The participation of renewables in adjustment services of the electric power system highlights the level of development these technologies have achieved. This means their integration into the grid can be increased, sometimes exceeding 70% of overall demand at a given moment in Spain without any negative effects on the quality, stability and security of the grid.
According to figures from REE, the volume of energy managed in the adjustment services of the Spanish power system in 2015 was 18,206 GWh – 6.8% of all the power generated – with an associated cost of EUR 1,040 million. The penetration of renewables in the total power generated on the Iberian Peninsula reached 36.9% last year, with a peak of 70.4% in coverage of instant power generation from wind power. This figure, a record that has not been beaten to date, was recorded on Nov. 21, 2015. In the first 11 months of 2016, renewables produced 42.2% of the electricity generated in Spain (not including the island power systems).